Texas Government Code - GOV'T § 403.003. Chief Clerk

(1) perform the duties of the comptroller when the comptroller is unavoidably absent or is incapable of discharging those duties;

(2) act as comptroller if the office of comptroller becomes vacant until a comptroller is appointed and qualified; and

(3) under the comptroller's direction, supervise the keeping of the books, records, and accounts of the office and perform other duties required by law or the comptroller.