Mimecast, North America Inc. Uses in Amendments to Option to Extend Clause

Amendments to Option to Extend from Amendment to Lease

This FIRST AMENDMENT TO LEASE (this Amendment) is entered into and effective as of the 19th day of October, 2015 (the First Amendment Effective Date) by and between RIVERWORKS WATERTOWN HOLDINGS, LLC, a Delaware limited liability company, as landlord (Landlord), as successor-in-interest to Farley White Aetna Mills, LLC, having an address for purposes hereof at One Market Plaza, Spear Tower, Suite 4125, San Francisco, California 94105, and MIMECAST NORTH AMERICA, INC., a Delaware corporation, as tenant (Tenant), having an address for purposes hereof at 480 Pleasant Street, Watertown, Massachusetts 02472.

Amendments to Option to Extend. Notwithstanding anything contained in the Existing Lease to the contrary. Landlord and Tenant agree that Tenants option to extend the Term pursuant to Section 10.23 of the Lease: (a) maybe exercised only with respect to the entire Premises (i.e., the Existing Premises and the First Expansion Premises) and not any part thereof; (b) unless Landlord expressly agrees otherwise, may only be exercised by Mimecast, North America Inc. (or any Affiliate which has succeeded to Tenants interest in the Lease in strict accordance with the terms and provisions contained in Section 6.3(b) of the Original Lease) and only if Mimecast North America, Inc. (or such Affiliate), both on the date of its extension exercise notice and on the first day of the Extended Term, remains the Tenant under the Lease and itself occupies at least seventy percent (70.0%) of the Premises (and if either such conditions are not satisfied, Landlord, at its option, may elect to void Tenants exercise of its option to extend by written notice to Tenant); and (c) must be exercised by written notice delivered to Landlord delivered on or before October 31, 2018, with time strictly of the essence.