NINETEENTH SUPPLEMENTAL INDENTURE CARRIZO OIL & GAS, INC., the Subsidiary Guarantors named herein and

Exhibit 4.3

NINETEENTH SUPPLEMENTAL INDENTURE

CARRIZO OIL & GAS, INC.,

the Subsidiary Guarantors named herein

and

XXXXX FARGO BANK, NATIONAL ASSOCIATION,

as Trustee

4.375% Convertible Senior Notes due 2028

May 20, 2015

TABLE OF CONTENTS

ARTICLE ONE GUARANTEE    2

SECTION 101    Guarantee.    2

ARTICLE TWO MISCELLANEOUS PROVISIONS    2

SECTION 201    Integral Part.    2

SECTION 202    General Definitions.    2

SECTION 203    Adoption, Ratification and Confirmation.    2

SECTION 204    The Trustee.    2

SECTION 205    Counterparts.    2

SECTION 206    Governing Law.    3

i

CARRIZO OIL & GAS, INC.

NINETEENTH SUPPLEMENTAL INDENTURE

THIS NINETEENTH SUPPLEMENTAL INDENTURE, dated as of May 20, 2015 is among Carrizo Oil & Gas, Inc., a Texas corporation (the “Company”), Carrizo (Permian) LLC, a Delaware limited liability company and a wholly-owned subsidiary of the Company (the “Guaranteeing Subsidiary”), the existing Subsidiary Guarantors (as defined in the Indenture referred to below) and Xxxxx Fargo Bank, National Association (the “Trustee”).

W I T N E S S E T H :

WHEREAS, the Company, certain of its Subsidiaries and the Trustee heretofore executed and delivered an Indenture, dated as of May 28, 2008 (as amended and supplemented by a First Supplemental Indenture among the Company, certain of its Subsidiaries, and the Trustee, dated May 28. 2008, a Second Supplemental Indenture among the Company, certain of its Subsidiaries, and the Trustee, dated as of May 14, 2009, a Third Supplemental Indenture among the Company, one of its Subsidiaries, and the Trustee, dated as of October 19, 2009, a Fifth Supplemental Indenture among the Company, certain of its Subsidiaries, and the Trustee, dated as of November 2, 2010, a Seventh Supplemental Indenture among the Company, certain of its Subsidiaries, and the Trustee, dated as of May 4, 2011, a Ninth Supplemental Indenture among the Company, certain of its Subsidiaries, and the Trustee, dated as of August 5, 2011, and a Thirteenth Supplemental Indenture among the Company, certain of its Subsidiaries, and the Trustee, dated as of November 6, 2012, the “Indenture”), providing for the issuance of the Company’s 4.375% Convertible Senior Notes due 2028 (the “Convertible Notes”) and Guarantees of the Convertible Notes by certain of the Company’s Subsidiaries;

WHEREAS, Section 4.08 of the Indenture provides that if at any time the Company issues Publicly Traded Debt Securities, and any Subsidiary Guarantor provides a Guarantee with respect to such Publicly Traded Debt Securities, then the Company will cause such Subsidiary Guarantor to guarantee the Convertible Notes as provided in Article X of the Indenture;

WHEREAS, on the date hereof, the Guaranteeing Subsidiary has provided a Guarantee with respect to (i) the Company’s 7.50% Senior Notes due 2020 and (ii) the Company’s 6.25% Senior Notes due 2023; and

WHEREAS, the Company, pursuant to the terms and provisions of the Indenture, proposes in and by this Supplemental Indenture to supplement and amend the Indenture insofar as it will apply only to the Convertible Notes in certain respects;

NOW, THEREFORE:

To comply with the provisions of the Indenture and in consideration of the premises provided for herein, the Guaranteeing Subsidiary, the Company, the existing Subsidiary Guarantors and the Trustee mutually covenant and agree for the equal and proportionate benefit of all Holders of the Convertible Notes as follows:

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ARTICLE ONE
GUARANTEE

SECTION 101 Guarantee.

The Guaranteeing Subsidiary hereby agrees by execution of this Supplemental Indenture, with respect to the Convertible Notes, to be bound by all of the provisions of the Indenture applicable to a Subsidiary Guarantor to the extent provided for in Article X of the Indenture.

ARTICLE TWO
MISCELLANEOUS PROVISIONS

SECTION 201 Integral Part.

This Supplemental Indenture constitutes an integral part of the Indenture.

SECTION 202 General Definitions.

For all purposes of this Supplemental Indenture:

(a)    capitalized terms used herein without definition shall have the meanings specified in the Indenture; and

(b)    the terms “herein,” “hereof,” “hereunder” and other words of similar import refer to this Supplemental Indenture.

SECTION 203     Adoption, Ratification and Confirmation.

The Indenture, as supplemented and amended by this Supplemental Indenture, is in all respects hereby adopted, ratified and confirmed.

SECTION 204     The Trustee.

The Trustee shall not be responsible in any manner whatsoever for or in respect of the validity or sufficiency of this Supplemental Indenture or for or in respect of the recitals contained herein, all of which recitals are made solely by the Company and the Subsidiary Guarantors named herein.

SECTION 205     Counterparts.

This Supplemental Indenture may be executed in any number of counterparts, each of which when so executed shall be deemed an original; and all such counterparts shall together constitute but one and the same instrument.

2

SECTION 206     Governing Law.

THIS SUPPLEMENTAL INDENTURE SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

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IN WITNESS WHEREOF, the parties hereto have caused this Nineteenth Supplemental Indenture to be duly executed as of the day and year first written above.

CARRIZO OIL & GAS, INC.
By:    /s/ Xxxxx X. Xxxxx        

Xxxxx X. Xxxxx     Vice President and Chief Financial Officer

GUARANTEEING SUBSIDIARY

CARRIZO (PERMIAN) LLC

By:    /s/ Xxxxx X. Xxxxx        

Xxxxx X. Xxxxx

Vice President and Chief Financial Officer

EXISTING SUBSIDIARY GUARANTORS

BANDELIER PIPELINE HOLDING, LLC

CARRIZO (EAGLE FORD) LLC

CARRIZO (MARCELLUS) LLC
CARRIZO (MARCELLUS) WV LLC
CARRIZO (NIOBRARA) LLC

CARRIZO (UTICA) LLC
CARRIZO MARCELLUS HOLDING INC.
CLLR, INC.
HONDO PIPELINE, INC.
MESCALERO PIPELINE, LLC

By:    /s/ Xxxxx X. Xxxxx        

Xxxxx X. Xxxxx     Vice President and Chief Financial Officer

Signature Page - Nineteenth Supplemental Indenture

XXXXX FARGO BANK, NATIONAL ASSOCIATION, as Trustee
By:    /s/ Xxxx X. Xxxxxxxxx             Xxxx X. Xxxxxxxxx     Vice President

Signature Page - Nineteenth Supplemental Indenture