Tex. Transp. Code § 456.063

The department, on behalf of the commission and with the approval of the comptroller, shall enter into an agreement, under terms and conditions the department considers appropriate, with an eligible corporation for the purposes of making a secured loan under this subchapter. The agreement must provide for collateralization and guaranties in a form and amount determined by the comptroller and the commission to be sufficient to repay to the state highway fund any money transferred to the general revenue fund under Section 456.062(b).