Tex. Business Organizations Code § 101.151: REQUIREMENTS FOR ENFORCEABLE PROMISE.

A promise to make a contribution or otherwise pay cash or transfer property to a limited liability company is enforceable only if the promise is:

(1) in writing; and

(2) signed by the person making the promise.

Acts 2003, 78th Leg., ch. 182, Sec. 1, eff. Jan. 1, 2006.