Common use of Trust Clause in Contracts

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 Portion of the Class 1-A-2 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 Class 1-A-2 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class 1-A-2 Principal Balance as of the Cut-Off Date: $50,000,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26, 2005. Interest is not payable with respect to this Certificate. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 Portion of the Class 1C-A-2 P Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 1,897,569.00 Class 1C-A-2 P Certificate Interest Rate: Variable 0.00% Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class 1C-A-2 P Principal Balance as of the Cut-Off Date: $50,000,000.00 1,897,569.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 BX9 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class B-1 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 Portion of the Class 1-A-2 A-1 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 13,552,800.00 Class 1-A-2 A-1 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class 1-A-2 A-1 Principal Balance as of the Cut-Off Date: $50,000,000.00 13,552,800.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 BD3 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 Portion of the Class 1C-A-2 Principal Balance X Notional Amount as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 14,369,296.00 Class 1C-A-2 X Certificate Interest Rate: Variable 5.500%, applied to the Class C-X Notional Amount Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class 1C-A-2 X Principal Balance as of the Cut-Off Date: $50,000,000.00 0.00 Class C-X Notional Amount as of the Cut-Off Date: $14,369,296.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 BW1 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class C-P Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26December 28, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 11 Portion of the Class 1-A-2 Principal Balance X Notional Amount as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 13,411,848.00 Class 1-A-2 X Certificate Interest Rate: Variable 5.750%, applied to the Class X Notional Amount Cut-Off Date: August December 1, 2005 First Distribution Date: September 26January 25, 2005 2006 Last Scheduled Distribution Date: September January 25, 2035 2036 Class 1-A-2 X Principal Balance as of the Cut-Off Date: $50,000,000.00 0.00 Class X Notional Amount as of the Cut-Off Date: $13,411,848.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 JF0 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class P Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES WaMu ASSET ACCEPTANCE CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 Portion of the Class 1-A-2 A-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 16,001,326.00 Class 1-A-2 A-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class 1-A-2 A-5 Principal Balance as of the Cut-Off Date: $50,000,000.00 16,001,326.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 BH4 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 Portion of the Class 12-A-2 CB-1 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 24,424,200.00 Class 12-A-2 CB-1 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September August 25, 2035 Class 12-A-2 CB-1 Principal Balance as of the Cut-Off Date: $50,000,000.00 24,424,200.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 BM3 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 2-CB-2 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 Portion of the Class 13-A-2 CB Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 37,805,200.00 Class 13-A-2 CB Certificate Interest Rate: Variable 6.500% Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September August 25, 2035 Class 13-A-2 CB Principal Balance as of the Cut-Off Date: $50,000,000.00 37,805,200.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 BU5 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 4-CB Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 Portion of the Class 12-A-2 CB-6 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 41,289,416.00 Class 12-A-2 CB-6 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September August 25, 2035 Class 12-A-2 CB-6 Principal Balance as of the Cut-Off Date: $50,000,000.00 41,289,416.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 BS0 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 2-CB-7 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. The Class 1-A-7 Certificates will provide credit support to another Class of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class 1-A-2 A-7 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 1,000,000.00 Class 1-A-2 A-7 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class 1-A-2 A-7 Principal Balance as of the Cut-Off Date: $50,000,000.00 1,000,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 BK7 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 1-A-8 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 Portion of the Class 12-A-2 CB-4 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 31,569,066.00 Class 12-A-2 CB-4 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September August 25, 2035 Class 12-A-2 CB-4 Principal Balance as of the Cut-Off Date: $50,000,000.00 31,569,066.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 BQ4 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 2-CB-5 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 Portion of the Class 14-A-2 CB Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 29,539,800.00 Class 14-A-2 CB Certificate Interest Rate: Variable 7.000% Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September August 25, 2035 Class 14-A-2 CB Principal Balance as of the Cut-Off Date: $50,000,000.00 29,539,800.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 BV3 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class C-X Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 Portion of the Class 12-A-2 CB-3 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 149,937,994.00 Class 12-A-2 CB-3 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September August 25, 2035 Class 12-A-2 CB-3 Principal Balance as of the Cut-Off Date: $50,000,000.00 149,937,994.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 BP6 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 2-CB-4 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 Portion of the Class 12-A-2 CB-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 31,022,740.00 Class 12-A-2 CB-5 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September August 25, 2035 Class 12-A-2 CB-5 Principal Balance as of the Cut-Off Date: $50,000,000.00 31,022,740.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 BR2 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 2-CB-6 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. The Class 2-CB-2 Certificates will provide credit support to other Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class 12-A-2 CB-2 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 4,195,000.00 Class 12-A-2 CB-2 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September August 25, 2035 Class 12-A-2 CB-2 Principal Balance as of the Cut-Off Date: $50,000,000.00 4,195,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 BN1 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 2-CB-3 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 Portion of the Class 1-A-2 A-8 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 4,215,000.00 Class 1-A-2 A-8 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class 1-A-2 A-8 Principal Balance as of the Cut-Off Date: $50,000,000.00 4,215,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 BL5 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 2-CB-1 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 Portion of the Class 1-A-2 A-4 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 59,304,107.00 Class 1-A-2 A-4 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class 1-A-2 A-4 Principal Balance as of the Cut-Off Date: $50,000,000.00 59,304,107.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 BG6 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 1-A-5 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26July 28, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 6 Portion of the Class 12-A-2 A-4 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 95,000,000.00 Class 12-A-2 A-4 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August July 1, 2005 First Distribution Date: September 26August 25, 2005 Last Scheduled Distribution Date: September August 25, 2035 Class 12-A-2 A-4 Principal Balance as of the Cut-Off Date: $50,000,000.00 95,000,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 92922F Y5 1 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26February 25, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. The Class 6-A-2 Certificates will provide credit support to another Class of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 1 Portion of the Class 16-A-2 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 530,400.00 Class 16-A-2 Certificate Interest Rate: Variable 6.500% Cut-Off Date: August February 1, 2005 First Distribution Date: September 26March 25, 2005 Last Scheduled Distribution Date: September March 25, 2035 Class 16-A-2 Principal Balance as of the Cut-Off DateBalance: $50,000,000.00 530,400.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 2S 1 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26January 30, 20052006. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 20052006-7 1 Portion of the Class 14-A-2 CB Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 115,632,000.00 Class 14-A-2 CB Certificate Interest Rate: Variable 6.500% Cut-Off Date: August January 1, 2005 2006 First Distribution Date: September 26February 27, 2005 2006 Last Scheduled Distribution Date: September February 25, 2035 2036 Class 14-A-2 CB Principal Balance as of the Cut-Off Date: $50,000,000.00 115,632,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 KZ 4 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 5-CB-1 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES WaMu ASSET ACCEPTANCE CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26October 27, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 9 Portion of the Class 15-A-2 A-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 39,349,100.00 Class 15-A-2 A-5 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August October 1, 2005 First Distribution Date: September 26November 25, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class 15-A-2 A-5 Principal Balance as of the Cut-Off Date: $50,000,000.00 39,349,100.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 FG2 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 5-A-6 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August April 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 3 Portion of the Class 12-A-2 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 34,500,000.00 Class 12-A-2 Certificate Interest Rate: Variable Cut-Off Date: August April 1, 2005 First Distribution Date: September 26May 25, 2005 Last Scheduled Distribution Date: September May 25, 2035 Class 12-A-2 Principal Balance as of the Cut-Off Date: $50,000,000.00 34,500,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 5G 4 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26October 27, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 9 Portion of the Class 15-A-2 A-3 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 26,673,768.00 Class 15-A-2 A-3 Certificate Interest Rate: Variable Cut-Off Date: August October 1, 2005 First Distribution Date: September 26November 25, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class 15-A-2 A-3 Principal Balance as of the Cut-Off Date: $50,000,000.00 26,673,768.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 FE7 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 5-A-4 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26October 27, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 9 Portion of the Class 14-A-2 A-1 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 11,448,000.00 Class 14-A-2 A-1 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August October 1, 2005 First Distribution Date: September 26November 25, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class 14-A-2 A-1 Principal Balance as of the Cut-Off Date: $50,000,000.00 11,448,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 EX6 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 4-A-2 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26October 27, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 9 Portion of the Class 14-A-2 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 Class 14-A-2 Certificate Interest Rate: Variable Cut-Off Date: August October 1, 2005 First Distribution Date: September 26November 25, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class 14-A-2 Principal Balance as of the Cut-Off Date: $50,000,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 EY4 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 4-A-3 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26November 29, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 10 Portion of the Class 12-A-2 A-6 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 35,454,950.00 Class 12-A-2 A-6 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August November 1, 2005 First Distribution Date: September 26December 27, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class 12-A-2 A-6 Principal Balance as of the Cut-Off Date: $50,000,000.00 35,454,950.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 GF3 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26February 25, 2005. Interest is not payable with respect to this Certificate. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 1 Portion of the Class 1C-A-2 P Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 Class 1C-A-2 P Certificate Interest Rate: Variable 0.00% $912,192.00 Cut-Off Date: August February 1, 2005 First Distribution Date: September 26March 25, 2005 Last Scheduled Distribution Date: September March 25, 2035 Class 1C-A-2 P Principal Balance as of the Cut-Off Date: $50,000,000.00 912,192.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 2Z 5 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 3-P Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26February 25, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. The Class 5-A-2 Certificates will provide credit support to another Class of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 1 Portion of the Class 15-A-2 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 1,760,500.00 Class 15-A-2 Certificate Interest Rate: Variable 6.000% Cut-Off Date: August February 1, 2005 First Distribution Date: September 26March 25, 2005 Last Scheduled Distribution Date: September March 25, 2035 Class 15-A-2 Principal Balance as of the Cut-Off DateBalance: $50,000,000.00 1,760,500.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 2Q 5 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26March 28, 2005. Interest is not payable with respect to this Certificate. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 2 Portion of the Class 1C-A-2 P Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 1,271,629.00 Class 1C-A-2 P Certificate Interest Rate: Variable 0.00% Cut-Off Date: August March 1, 2005 First Distribution Date: September 26April 25, 2005 Last Scheduled Distribution Date: September April 25, 2035 Class 1C-A-2 P Principal Balance as of the Cut-Off Date: $50,000,000.00 1,271,629.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 3Y 7 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 3-P Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August April 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 3 Portion of the Class 1-A-2 CB-1 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 39,748,000.00 Class 1-A-2 CB-1 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August April 1, 2005 First Distribution Date: September 26May 25, 2005 Last Scheduled Distribution Date: September May 25, 2035 Class 1-A-2 CB-1 Principal Balance as of the Cut-Off Date: $50,000,000.00 39,748,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 4Z 3 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 1-CB-2 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26October 27, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 9 Portion of the Class 12-A-2 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 106,010,500.00 Class 12-A-2 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August October 1, 2005 First Distribution Date: September 26November 25, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class 12-A-2 Principal Balance as of the Cut-Off Date: $50,000,000.00 106,010,500.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 EP3 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26July 28, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 6 Portion of the Class 13-A-2 CB Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 96,253,000.00 Class 13-A-2 CB Certificate Interest Rate: Variable 5.500% Cut-Off Date: August July 1, 2005 First Distribution Date: September 26August 25, 2005 Last Scheduled Distribution Date: September August 25, 2035 Class 13-A-2 CB Principal Balance as of the Cut-Off Date: $50,000,000.00 96,253,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 92922F Z4 3 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class C-X Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26July 28, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 6 Portion of the Class 12-A-2 A-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 39,531,000.00 Class 12-A-2 A-5 Certificate Interest Rate: Variable Cut-Off Date: August July 1, 2005 First Distribution Date: September 26August 25, 2005 Last Scheduled Distribution Date: September August 25, 2035 Class 12-A-2 A-5 Principal Balance as of the Cut-Off Date: $50,000,000.00 39,531,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 92922F Y6 9 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26May 25, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 4 Portion of the Class 1-A-2 Principal Balance CB-16 Notional Amount as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 53,545.00 Class 1-A-2 CB-16 Certificate Interest Rate: Variable 5.50% Cut-Off Date: August May 1, 2005 First Distribution Date: September 26June 27, 2005 Last Scheduled Distribution Date: September June 25, 2035 Class 1-A-2 CB-16 Principal Balance as of the Cut-Off Date: $50,000,000.00 0.00 Class CB-16 Notional Amount as of the Cut-Off Date: $53,545.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 6M 0 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 2-CB Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26November 29, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 10 Portion of the Class 14-A-2 CB-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 5,696,525.00 Class 14-A-2 CB-5 Certificate Interest Rate: Variable 6.000% Cut-Off Date: August November 1, 2005 First Distribution Date: September 26December 27, 2005 Last Scheduled Distribution Date: September December 25, 2035 Class 14-A-2 CB-5 Principal Balance as of the Cut-Off Date: $50,000,000.00 5,696,525.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 GR7 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 4-CB-6 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26January 30, 20052006. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 20052006-7 1 Portion of the Class 1C-A-2 P Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 4,420,231.00 Class 1C-A-2 P Certificate Interest Rate: Variable 0.00% Cut-Off Date: August January 1, 2005 2006 First Distribution Date: September 26February 27, 2005 2006 Last Scheduled Distribution Date: September February 25, 2035 2036 Class 1C-A-2 P Principal Balance as of the Cut-Off Date: $50,000,000.00 4,420,231.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 LH 3 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class B-1 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES WaMu ASSET ACCEPTANCE CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26November 29, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 10 Portion of the Class 12-A-2 A-1 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 26,790,200.00 Class 12-A-2 A-1 Certificate Interest Rate: Variable 5.750% Cut-Off Date: August November 1, 2005 First Distribution Date: September 26December 27, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class 12-A-2 A-1 Principal Balance as of the Cut-Off Date: $50,000,000.00 26,790,200.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 GA4 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26November 29, 2005. Interest is not payable with respect to this Certificate. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 10 Portion of the Class 12-A-2 A-10 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 597,363.00 Class 12-A-2 A-10 Certificate Interest Rate: Variable 0.00% Cut-Off Date: August November 1, 2005 First Distribution Date: September 26December 27, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class 12-A-2 A-10 Principal Balance as of the Cut-Off Date: $50,000,000.00 597,363.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 GJ5 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 3-CB-1 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26October 27, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 9 Portion of the Class 12-A-2 A-1 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 22,300,000.00 Class 12-A-2 A-1 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August October 1, 2005 First Distribution Date: September 26November 25, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class 12-A-2 A-1 Principal Balance as of the Cut-Off Date: $50,000,000.00 22,300,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 EN8 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26October 27, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 9 Portion of the Class 15-A-2 A-9 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 4,937,000.00 Class 15-A-2 A-9 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August October 1, 2005 First Distribution Date: September 26November 25, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class 15-A-2 A-9 Principal Balance as of the Cut-Off Date: $50,000,000.00 4,937,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 FN7 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class C-X Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August April 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 3 Portion of the Class 1C-A-2 Principal Balance X Notional Amount as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 32,241,010.00 Class 1C-A-2 X Certificate Interest Rate: Variable 5.500% applied to the Class C-X Notional Amount Cut-Off Date: August April 1, 2005 First Distribution Date: September 26May 25, 2005 Last Scheduled Distribution Date: September May 25, 2035 Class 1C-A-2 X Principal Balance as of the Cut-Off Date: $50,000,000.00 0.00 Class C-X Notional Amount as of the Cut-Off Date: $32,241,010.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 5M 1 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class C-P Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26October 27, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 9 Portion of the Class 12-A-2 A-3 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 24,612,300.00 Class 12-A-2 A-3 Certificate Interest Rate: Variable Cut-Off Date: August October 1, 2005 First Distribution Date: September 26November 25, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class 12-A-2 A-3 Principal Balance as of the Cut-Off Date: $50,000,000.00 24,612,300.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 EQ1 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26October 27, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 9 Portion of the Class 13-A-2 CB Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 21,143,300.00 Class 13-A-2 CB Certificate Interest Rate: Variable 5.500% Cut-Off Date: August October 1, 2005 First Distribution Date: September 26November 25, 2005 Last Scheduled Distribution Date: September October 25, 2035 2020 Class 13-A-2 CB Principal Balance as of the Cut-Off Date: $50,000,000.00 21,143,300.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 EW8 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 4-A-1 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26May 25, 2005. Interest is not payable with respect to this Certificate. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 4 Portion of the Class 1D-A-2 P Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 2,019,462.00 Class 1D-A-2 P Certificate Interest Rate: Variable 0.00% Cut-Off Date: August May 1, 2005 First Distribution Date: September 26June 27, 2005 Last Scheduled Distribution Date: September June 25, 2035 2020 Class 1D-A-2 P Principal Balance as of the Cut-Off Date: $50,000,000.00 2,019,462.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 7F 4 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class B-1 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26October 27, 2005. Interest is not payable with respect to this Certificate. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 9 Portion of the Class 1C-A-2 P Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 1,128,110.00 Class 1C-A-2 P Certificate Interest Rate: Variable 0.00% Cut-Off Date: August October 1, 2005 First Distribution Date: September 26November 25, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class 1C-A-2 P Principal Balance as of the Cut-Off Date: $50,000,000.00 1,128,110.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 FQ0 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class B-1 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26May 25, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 4 Portion of the Class 1-A-2 CB-1 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 305,066,700.00 Class 1-A-2 CB-1 Certificate Interest Rate: Variable Cut-Off Date: August May 1, 2005 First Distribution Date: September 26June 27, 2005 Last Scheduled Distribution Date: September June 25, 2035 Class 1-A-2 CB-1 Principal Balance as of the Cut-Off Date: $50,000,000.00 305,066,700.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 5W 9 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class CB-2 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August April 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 3 Portion of the Class 12-A-2 Principal Balance A-4 Notional Amount as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 46,317,000.00 Class 12-A-2 A-4 Certificate Interest Rate: Variable Variable, applied to the Class 2-A-4 Notional Amount Cut-Off Date: August April 1, 2005 First Distribution Date: September 26May 25, 2005 Last Scheduled Distribution Date: September May 25, 2035 Class 12-A-2 A-4 Principal Balance as of the Cut-Off Date: $50,000,000.00 0.00 Class 2-A-4 Notional Amount as of the Cut-Off Date: $46,317,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 5J 8 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August April 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 3 Portion of the Class 12-A-2 A-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 2,614,000.00 Class 12-A-2 A-5 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August April 1, 2005 First Distribution Date: September 26May 25, 2005 Last Scheduled Distribution Date: September May 25, 2035 Class 12-A-2 A-5 Principal Balance as of the Cut-Off DateBalance: $50,000,000.00 2,614,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 5K 5 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26March 28, 2005. Interest is not payable with respect to this Certificate. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 2 Portion of the Class 13-A-2 P Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 1,225,835.00 Class 13-A-2 P Certificate Interest Rate: Variable 0.00% Cut-Off Date: August March 1, 2005 First Distribution Date: September 26April 25, 2005 Last Scheduled Distribution Date: September April 25, 2035 2020 Class 13-A-2 P Principal Balance as of the Cut-Off Date: $50,000,000.00 1,225,835.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 3Z 4 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class B-1 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26October 27, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 9 Portion of the Class 12-A-2 A-4 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 36,050,000.00 Class 12-A-2 A-4 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August October 1, 2005 First Distribution Date: September 26November 25, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class 12-A-2 A-4 Principal Balance as of the Cut-Off Date: $50,000,000.00 36,050,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 ER9 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 2-A-5 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26March 28, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 2 Portion of the Class 12-A-2 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 50,336,000.00 Class 12-A-2 Certificate Interest Rate: Variable Cut-Off Date: August March 1, 2005 First Distribution Date: September 26April 25, 2005 Last Scheduled Distribution Date: September April 25, 2035 Class 12-A-2 Principal Balance as of the Cut-Off Date: $50,000,000.00 50,336,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 3R 2 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26July 28, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 6 Portion of the Class 12-A-2 A-3 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 4,252,334.00 Class 12-A-2 A-3 Certificate Interest Rate: Variable Cut-Off Date: August July 1, 2005 First Distribution Date: September 26August 25, 2005 Last Scheduled Distribution Date: September August 25, 2035 Class 12-A-2 A-3 Principal Balance as of the Cut-Off Date: $50,000,000.00 4,252,334.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 92922F Y4 4 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26July 28, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 6 Portion of the Class 1-A-2 CB Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 47,772,000.00 Class 1-A-2 CB Certificate Interest Rate: Variable 6.500% Cut-Off Date: August July 1, 2005 First Distribution Date: September 26August 25, 2005 Last Scheduled Distribution Date: September August 25, 2035 Class 1-A-2 CB Principal Balance as of the Cut-Off Date: $50,000,000.00 47,772,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 92922F X9 4 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26March 28, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. The Class 2-A-6 Certificates will provide credit support to another Class of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 2 Portion of the Class 12-A-2 A-6 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 305,000.00 Class 12-A-2 A-6 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August March 1, 2005 First Distribution Date: September 26April 25, 2005 Last Scheduled Distribution Date: September April 25, 2035 Class 12-A-2 A-6 Principal Balance as of the Cut-Off DateBalance: $50,000,000.00 305,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 3V 3 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 3-A Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26July 28, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 6 Portion of the Class 12-A-2 A-9 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 3,925,100.00 Class 12-A-2 A-9 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August July 1, 2005 First Distribution Date: September 26August 25, 2005 Last Scheduled Distribution Date: September August 25, 2035 Class 12-A-2 A-9 Principal Balance as of the Cut-Off Date: $50,000,000.00 3,925,100.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 92922F Z5 0 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26May 25, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 4 Portion of the Class 1-A-2 CB-3 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 154,500,000.00 Class 1-A-2 CB-3 Certificate Interest Rate: Variable Cut-Off Date: August May 1, 2005 First Distribution Date: September 26June 27, 2005 Last Scheduled Distribution Date: September June 25, 2035 Class 1-A-2 CB-3 Principal Balance as of the Cut-Off Date: $50,000,000.00 154,500,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 5Y 5 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class CB-4 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26November 29, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 10 Portion of the Class 12-A-2 A-7 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 25,000,000.00 Class 12-A-2 A-7 Certificate Interest Rate: Variable 5.750% Cut-Off Date: August November 1, 2005 First Distribution Date: September 26December 27, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class 12-A-2 A-7 Principal Balance as of the Cut-Off Date: $50,000,000.00 25,000,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 GG1 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26November 29, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 10 Portion of the Class 12-A-2 A-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 76,220,000.00 Class 12-A-2 A-5 Certificate Interest Rate: Variable 5.750% Cut-Off Date: August November 1, 2005 First Distribution Date: September 26December 27, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class 12-A-2 A-5 Principal Balance as of the Cut-Off Date: $50,000,000.00 76,220,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 GE6 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26January 30, 20052006. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 20052006-7 1 Portion of the Class 12-A-2 CB-2 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 13,000,000.00 Class 12-A-2 CB-2 Certificate Interest Rate: Variable 7.000% Cut-Off Date: August January 1, 2005 2006 First Distribution Date: September 26February 27, 2005 2006 Last Scheduled Distribution Date: September February 25, 2035 2036 Class 12-A-2 CB-2 Principal Balance as of the Cut-Off Date: $50,000,000.00 13,000,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 KM 3 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 2-CB-3 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES WaMu ASSET ACCEPTANCE CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26November 29, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 10 Portion of the Class 12-A-2 A-8 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 35,454,950.00 Class 12-A-2 A-8 Certificate Interest Rate: Variable 6.000% Cut-Off Date: August November 1, 2005 First Distribution Date: September 26December 27, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class 12-A-2 A-8 Principal Balance as of the Cut-Off Date: $50,000,000.00 35,454,950.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 GH9 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26July 28, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 6 Portion of the Class 12-A-2 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 46,775,666.00 Class 12-A-2 Certificate Interest Rate: Variable Cut-Off Date: August July 1, 2005 First Distribution Date: September 26August 25, 2005 Last Scheduled Distribution Date: September August 25, 2035 Class 12-A-2 Principal Balance as of the Cut-Off Date: $50,000,000.00 46,775,666.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 92922F Y3 6 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26July 28, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 6 Portion of the Class 12-A-2 A-8 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 29,000,000.00 Class 12-A-2 A-8 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August July 1, 2005 First Distribution Date: September 26August 25, 2005 Last Scheduled Distribution Date: September August 25, 2035 Class 12-A-2 A-8 Principal Balance as of the Cut-Off Date: $50,000,000.00 29,000,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 92922F Y9 3 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August April 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 3 Portion of the Class 1-A-2 Principal Balance CB-4 Notional Amount as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 356,447,000.00 Class 1-A-2 CB-4 Certificate Interest Rate: Variable Variable, applied to the Class 1-CB-4 Notional Amount Cut-Off Date: August April 1, 2005 First Distribution Date: September 26May 25, 2005 Last Scheduled Distribution Date: September May 25, 2035 Class 1-A-2 CB-4 Principal Balance as of the Cut-Off Date: $50,000,000.00 0.00 Class 1-CB-4 Notional Amount as of the Cut-Off Date: $356,447,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 5C 3 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 1-CB-5 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August April 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 3 Portion of the Class 12-A-2 A-3 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 46,317,000.00 Class 12-A-2 A-3 Certificate Interest Rate: Variable Cut-Off Date: August April 1, 2005 First Distribution Date: September 26May 25, 2005 Last Scheduled Distribution Date: September May 25, 2035 Class 12-A-2 A-3 Principal Balance as of the Cut-Off Date: $50,000,000.00 46,317,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 5H 2 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26November 29, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 10 Portion of the Class 14-A-2 CB-1 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 12,763,000.00 Class 14-A-2 CB-1 Certificate Interest Rate: Variable 5.750% Cut-Off Date: August November 1, 2005 First Distribution Date: September 26December 27, 2005 Last Scheduled Distribution Date: September December 25, 2035 Class 14-A-2 CB-1 Principal Balance as of the Cut-Off Date: $50,000,000.00 12,763,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 GM8 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 4-CB-2 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26May 25, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. The Class CB-8 Certificates will provide credit support to another Class of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 4 Portion of the Class 1-A-2 CB-8 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 3,576,900.00 Class 1-A-2 CB-8 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August May 1, 2005 First Distribution Date: September 26June 27, 2005 Last Scheduled Distribution Date: September June 25, 2035 Class 1-A-2 CB-8 Principal Balance as of the Cut-Off Date: $50,000,000.00 3,576,900.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 6D 0 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class CB-9 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26July 28, 2005. Interest is not payable with respect to this Certificate. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 6 Portion of the Class 1C-A-2 Principal PPrincipal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 349,561.00 Class 1C-A-2 Certificate PCertificate Interest Rate: Variable 0.00% Cut-Off Date: August July 1, 2005 First Distribution Date: September 26August 25, 2005 Last Scheduled Distribution Date: September August 25, 2035 Class 1C-A-2 Principal PPrincipal Balance as of the Cut-Off Date: $50,000,000.00 349,561.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 92922F Z9 2 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class B-1 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26November 29, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 10 Portion of the Class 13-A-2 CB-1 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 109,200,200.00 Class 13-A-2 CB-1 Certificate Interest Rate: Variable 6.000% Cut-Off Date: August November 1, 2005 First Distribution Date: September 26December 27, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class 13-A-2 CB-1 Principal Balance as of the Cut-Off Date: $50,000,000.00 109,200,200.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 GK2 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 3-CB-2 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26January 30, 20052006. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 20052006-7 1 Portion of the Class 15-A-2 CB-1 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 24,308,000.00 Class 15-A-2 CB-1 Certificate Interest Rate: Variable 5.750% Cut-Off Date: August January 1, 2005 2006 First Distribution Date: September 26February 27, 2005 2006 Last Scheduled Distribution Date: September February 25, 2035 2036 Class 15-A-2 CB-1 Principal Balance as of the Cut-Off Date: $50,000,000.00 24,308,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 LA 8 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 5-CB-2 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES WaMu ASSET ACCEPTANCE CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26January 30, 20052006. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 20052006-7 1 Portion of the Class 15-A-2 CB-4 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 184,322,400.00 Class 15-A-2 CB-4 Certificate Interest Rate: Variable 5.750% Cut-Off Date: August January 1, 2005 2006 First Distribution Date: September 26February 27, 2005 2006 Last Scheduled Distribution Date: September February 25, 2035 2036 Class 15-A-2 CB-4 Principal Balance as of the Cut-Off Date: $50,000,000.00 184,322,400.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 LD 2 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 5-CB-5 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES WaMu ASSET ACCEPTANCE CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26February 25, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 1 Portion of the Class 1-A-2 A-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 20,442,400.00 Class 1-A-2 A-5 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August February 1, 2005 First Distribution Date: September 26March 25, 2005 Last Scheduled Distribution Date: September March 25, 2035 Class 1-A-2 A-5 Principal Balance as of the Cut-Off Date: $50,000,000.00 20,442,400.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 2J 1 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 1-A-6 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August April 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. The Class 2-A-6 Certificates will provide credit support to another Class of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 3 Portion of the Class 12-A-2 A-6 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 455,000.00 Class 12-A-2 A-6 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August April 1, 2005 First Distribution Date: September 26May 25, 2005 Last Scheduled Distribution Date: September May 25, 2035 Class 12-A-2 A-6 Principal Balance as of the Cut-Off DateBalance: $50,000,000.00 455,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 5L 3 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class C-X Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26October 27, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 9 Portion of the Class 15-A-2 A-1 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 13,211,400.00 Class 15-A-2 A-1 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August October 1, 2005 First Distribution Date: September 26November 25, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class 15-A-2 A-1 Principal Balance as of the Cut-Off Date: $50,000,000.00 13,211,400.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 FC1 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 5-A-2 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26January 29, 20052007. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 20052007-7 1 Portion of the Class 1-A-2 A-7 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 70,000,000.00 Class 1-A-2 A-7 Certificate Interest Rate: Variable Cut-Off Date: August January 1, 2005 2007 First Distribution Date: September February 26, 2005 2007 Last Scheduled Distribution Date: September February 25, 2035 2037 Class 1-A-2 A-7 Principal Balance as of the Cut-Off Date: $50,000,000.00 70,000,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 00000XXX0 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another trust that owns a pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WaMu ASSET ACCEPTANCE CORP. This Certificate is issued by Washington Mutual Mortgage Pass-Through Certificates WMALT Series 2007-1 Trust. This Certificate represents ownership of one or more “regular interests” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is January 29, 2007. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. This Certificate is an Initial Exchangeable Certificate, as described in the Pooling Agreement. WMALT Series 2007-1 Portion of the Class 1-A-8 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $62,761,300.00 Class 1-A-8 Certificate Interest Rate: 6.000% Cut-Off Date: January 1, 2007 First Distribution Date: February 26, 2007 Last Scheduled Distribution Date: February 25, 2037 Class 1-A-8 Principal Balance as of the Cut-Off Date: $62,761,300.00 Cede & Co. Registered Owner Exhibit A CUSIP 00000XXX0 WASHINGTON MUTUAL MORTGAGE SECURITIES PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a trust that owns a pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WaMu ASSET ACCEPTANCE CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26July 28, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 6 Portion of the Class 12-A-2 A-1 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 44,055,000.00 Class 12-A-2 A-1 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August July 1, 2005 First Distribution Date: September 26August 25, 2005 Last Scheduled Distribution Date: September August 25, 2035 Class 12-A-2 A-1 Principal Balance as of the Cut-Off Date: $50,000,000.00 44,055,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 92922F Y2 8 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August April 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. The Class 1-CB-6 Certificates will provide credit support to another Class of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 3 Portion of the Class 1-A-2 CB-6 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 8,770,300.00 Class 1-A-2 CB-6 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August April 1, 2005 First Distribution Date: September 26May 25, 2005 Last Scheduled Distribution Date: September May 25, 2035 Class 1-A-2 CB-6 Principal Balance as of the Cut-Off Date: $50,000,000.00 8,770,300.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 5E 9 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26October 27, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 9 Portion of the Class 12-A-2 A-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 4,600,000.00 Class 12-A-2 A-5 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August October 1, 2005 First Distribution Date: September 26November 25, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class 12-A-2 A-5 Principal Balance as of the Cut-Off Date: $50,000,000.00 4,600,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 ES7 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 2-A-6 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26May 25, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. The Class 5-A-10 Certificates will provide credit support to another Class of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 4 Portion of the Class 15-A-2 A-10 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 445,000.00 Class 15-A-2 A-10 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August May 1, 2005 First Distribution Date: September 26June 27, 2005 Last Scheduled Distribution Date: September June 25, 2035 Class 15-A-2 A-10 Principal Balance as of the Cut-Off DateBalance: $50,000,000.00 445,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 7B 3 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class C-X Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26March 28, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 2 Portion of the Class 1-A-2 A-3 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 281,002,000.00 Class 1-A-2 A-3 Certificate Interest Rate: Variable Cut-Off Date: August March 1, 2005 First Distribution Date: September 26April 25, 2005 Last Scheduled Distribution Date: September April 25, 2035 Class 1-A-2 A-3 Principal Balance as of the Cut-Off Date: $50,000,000.00 281,002,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 3L 5 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 1-A-4 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26November 29, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 10 Portion of the Class 15-A-2 A Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 30,190,000.00 Class 15-A-2 A Certificate Interest Rate: Variable 5.500% Cut-Off Date: August November 1, 2005 First Distribution Date: September 26December 27, 2005 Last Scheduled Distribution Date: September November 25, 2035 2020 Class 15-A-2 A Principal Balance as of the Cut-Off Date: $50,000,000.00 30,190,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 GS5 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class C-X Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26November 29, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 10 Portion of the Class 12-A-2 A-9 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 13,739,337.00 Class 12-A-2 A-9 Certificate Interest Rate: Variable 6.000% Cut-Off Date: August November 1, 2005 First Distribution Date: September 26December 27, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class 12-A-2 A-9 Principal Balance as of the Cut-Off Date: $50,000,000.00 13,739,337.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 HU9 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 2-A-10 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August April 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 3 Portion of the Class 1-A-2 CB-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 10,953,000.00 Class 1-A-2 CB-5 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August April 1, 2005 First Distribution Date: September 26May 25, 2005 Last Scheduled Distribution Date: September May 25, 2035 Class 1-A-2 CB-5 Principal Balance as of the Cut-Off Date: $50,000,000.00 10,953,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 5D 1 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 1-CB-6 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August April 26, 2005. Interest is not payable with respect to this Certificate. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 3 Portion of the Class 1C-A-2 P Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 2,059,478.00 Class 1C-A-2 P Certificate Interest Rate: Variable 0.00% Cut-Off Date: August April 1, 2005 First Distribution Date: September 26May 25, 2005 Last Scheduled Distribution Date: September May 25, 2035 Class 1C-A-2 P Principal Balance as of the Cut-Off Date: $50,000,000.00 2,059,478.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 5N 9 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class B-1 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26May 25, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. The Class 4-A-2 Certificates will provide credit support to another Class of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 4 Portion of the Class 14-A-2 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 1,484,000.00 Class 14-A-2 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August May 1, 2005 First Distribution Date: September 26June 27, 2005 Last Scheduled Distribution Date: September June 25, 2035 2020 Class 14-A-2 Principal Balance as of the Cut-Off DateBalance: $50,000,000.00 1,484,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 6R 9 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26May 25, 2005. Interest is not payable with respect to this Certificate. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 4 Portion of the Class 1C-A-2 P Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 2,742,845.00 Class 1C-A-2 P Certificate Interest Rate: Variable 0.00% Cut-Off Date: August May 1, 2005 First Distribution Date: September 26June 27, 2005 Last Scheduled Distribution Date: September June 25, 2035 Class 1C-A-2 P Principal Balance as of the Cut-Off Date: $50,000,000.00 2,742,845.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 7E 7 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class D-P Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August April 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 3 Portion of the Class 1-A-2 CB-3 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 356,447,000.00 Class 1-A-2 CB-3 Certificate Interest Rate: Variable Cut-Off Date: August April 1, 2005 First Distribution Date: September 26May 25, 2005 Last Scheduled Distribution Date: September May 25, 2035 Class 1-A-2 CB-3 Principal Balance as of the Cut-Off Date: $50,000,000.00 356,447,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 5B 5 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 1-CB-4 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26November 29, 2005. Interest is not payable with respect to this Certificate. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 10 Portion of the Class 14-A-2 CB-6 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 247,675.00 Class 14-A-2 CB-6 Certificate Interest Rate: Variable 0.00% Cut-Off Date: August November 1, 2005 First Distribution Date: September 26December 27, 2005 Last Scheduled Distribution Date: September December 25, 2035 Class 14-A-2 CB-6 Principal Balance as of the Cut-Off Date: $50,000,000.00 247,675.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 HT2 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 5-A Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26October 27, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 9 Portion of the Class 14-A-2 A-4 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 12,231,900.00 Class 14-A-2 A-4 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August October 1, 2005 First Distribution Date: September 26November 25, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class 14-A-2 A-4 Principal Balance as of the Cut-Off Date: $50,000,000.00 12,231,900.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 FA5 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 4-A-5 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August April 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT The Class 1-CB-2 Certificates will provide credit support to another Class of Certificates, as described in the Pooling Agreement. Series 2005-7 3 Portion of the Class 1-A-2 CB-2 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 2,049,000.00 Class 1-A-2 CB-2 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August April 1, 2005 First Distribution Date: September 26May 25, 2005 Last Scheduled Distribution Date: September May 25, 2035 Class 1-A-2 CB-2 Principal Balance as of the Cut-Off Date: $50,000,000.00 2,049,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 5A 7 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 1-CB-3 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26March 28, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. The Class 2-A-4 Certificates will provide credit support to another Class of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 2 Portion of the Class 12-A-2 A-4 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 2,650,000.00 Class 12-A-2 A-4 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August March 1, 2005 First Distribution Date: September 26April 25, 2005 Last Scheduled Distribution Date: September April 25, 2035 Class 12-A-2 A-4 Principal Balance as of the Cut-Off DateBalance: $50,000,000.00 2,650,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 3T 8 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26October 27, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 9 Portion of the Class 15-A-2 A-6 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 25,000,000.00 Class 15-A-2 A-6 Certificate Interest Rate: Variable Cut-Off Date: August October 1, 2005 First Distribution Date: September 26November 25, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class 15-A-2 A-6 Principal Balance as of the Cut-Off Date: $50,000,000.00 25,000,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 FH0 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 5-A-7 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26November 29, 2005. Interest is not payable with respect to this Certificate. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 10 Portion of the Class 1C-A-2 P Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 8,882,888.00 Class 1C-A-2 P Certificate Interest Rate: Variable 0.00% Cut-Off Date: August November 1, 2005 First Distribution Date: September 26December 27, 2005 Last Scheduled Distribution Date: September December 25, 2035 Class 1C-A-2 P Principal Balance as of the Cut-Off Date: $50,000,000.00 8,882,888.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 GU0 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class B-1 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26November 29, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 10 Portion of the Class 14-A-2 CB-3 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 117,923,200.00 Class 14-A-2 CB-3 Certificate Interest Rate: Variable Cut-Off Date: August November 1, 2005 First Distribution Date: September 26December 27, 2005 Last Scheduled Distribution Date: September December 25, 2035 Class 14-A-2 CB-3 Principal Balance as of the Cut-Off Date: $50,000,000.00 117,923,200.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 GP1 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 4-CB-4 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26November 29, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 10 Portion of the Class 1-A-2 CB Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 62,532,200.00 Class 1-A-2 CB Certificate Interest Rate: Variable 6.500% Cut-Off Date: August November 1, 2005 First Distribution Date: September 26December 27, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class 1-A-2 CB Principal Balance as of the Cut-Off Date: $50,000,000.00 62,532,200.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 FZ0 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26February 25, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. The Class 7-A-4 Certificates will provide credit support to another Class of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 1 Portion of the Class 17-A-2 A-4 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 226,200.00 Class 17-A-2 A-4 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August February 1, 2005 First Distribution Date: September 26March 25, 2005 Last Scheduled Distribution Date: September March 25, 2035 Class 17-A-2 A-4 Principal Balance as of the Cut-Off DateBalance: $50,000,000.00 226,200.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 2W 2 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class C-X Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26November 29, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 10 Portion of the Class 12-A-2 A-3 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 73,950,000.00 Class 12-A-2 A-3 Certificate Interest Rate: Variable Cut-Off Date: August November 1, 2005 First Distribution Date: September 26December 27, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class 12-A-2 A-3 Principal Balance as of the Cut-Off Date: $50,000,000.00 73,950,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 GC0 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26January 30, 20052006. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 20052006-7 1 Portion of the Class 15-A-2 CB-3 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 8,652,000.00 Class 15-A-2 CB-3 Certificate Interest Rate: Variable 5.750% Cut-Off Date: August January 1, 2005 2006 First Distribution Date: September 26February 27, 2005 2006 Last Scheduled Distribution Date: September February 25, 2035 2036 Class 15-A-2 CB-3 Principal Balance as of the Cut-Off Date: $50,000,000.00 8,652,000.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 LC 4 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class 5-CB-4 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES WaMu ASSET ACCEPTANCE CORP.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended, together with certain rights specified in the Pooling Agreement. The issue date of this Certificate is August 26February 25, 2005. Interest is not payable with respect to this Certificate. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. WMALT Series 2005-7 1 Portion of the Class 13-A-2 P Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $50,000,000.00 Class 13-A-2 P Certificate Interest Rate: Variable 0.00% $224,290.00 Cut-Off Date: August February 1, 2005 First Distribution Date: September 26March 25, 2005 Last Scheduled Distribution Date: September March 25, 2035 2020 Class 13-A-2 P Principal Balance as of the Cut-Off Date: $50,000,000.00 224,290.00 Cede & Co. Registered Owner Exhibit A CUSIP 93934F BE1 939336 3A 9 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Class B-1 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.