Tex. Natural Resources Code § 162.013

A loan under this chapter shall bear a fixed, variable, floating, or other rate or rates of interest determined by the board. The board may set the interest rate or rates to provide a margin over the rate paid by the board on its bonds issued under this chapter. The difference between the cost of the money to the board and the interest rate or rates charged to a veteran may be used in whole or in part to defray the expense of administering the program. To assure the maximum benefit of the program to the veteran, the board shall adopt rules relative to the fees, charges, and interest rates charged by the lending institutions on the financing of the home with money other than from the fund and shall limit to the maximum extent practical such fees, charges, and interest rates to those which would be collected by the lending institution in the normal course of its residential mortgage lending business.