Tenn. Code Ann. § 67-5-1209

The tax levied by this part shall not apply to the balance of the corporate property and capital stock, otherwise subject to valuation and assessment under §§ 67-5-1202(2) and 67-5-1203(b), of any pure captive insurance company, as defined in § 56-13-102 or of any entity operating in a similar manner to a pure captive insurance company such that fifty-one percent (51%) or more of its direct written premium revenue is from an affiliated company, as defined in § 56-13-102, or an associated company, as defined in § 56-13-102.