An agreement that tends to diminish or defeat the interest of the conservator or liquidating agent in an asset acquired under this chapter, either as security for a loan or by purchase, is not valid against the conservator or liquidating agent unless the agreement is:
(1) in writing;
(2) executed by the credit union and each person claiming an adverse interest under the agreement, including the obligor, contemporaneously with the acquisition of the asset by the credit union;
(3) approved by the board with the approval recorded in the minutes of the board; and
(4) an official record of the credit union continuously from the time of its execution.
Official text of the Texas Finance Code as published by the Texas Legislative Council.