Tex. Gov't Code § 404.049

Money received by the comptroller as trustee of funds in the treasury shall be kept in the treasury. The comptroller may not keep or receive into the treasury money, or the representative of money, belonging to an individual except as provided by law. The comptroller may not appropriate to the comptroller's own use or lend, sell, or exchange money, or the representative of money, in the comptroller's custody or control.