Tenn. Code Ann. § 67-8-401

The commissioner of revenue, referred to as “commissioner” in this part, has full supervision of the administration and enforcement of this part and part 3 of this chapter and of the collection of all taxes imposed thereunder, and shall make such rules and regulations as may be necessary for its proper interpretation and enforcement, and the commissioner is empowered to call upon other departments of state government for such information and assistance as the commissioner may deem necessary; provided, that the cost of administering this part and part 3 of this chapter shall not exceed three percent (3%) of the total tax collection.