Tenn. Code Ann. § 8-36-305: Minimum allowances

(a) The minimum early service retirement allowance payable to any member in Group 1, 2 or 3 shall be the minimum service retirement allowance computed in accordance with § 8-36-209(a) on the basis of the member's creditable service at the time of early retirement, reduced by four-tenths of one percent (0.4%) for each month by which the member's date of early retirement precedes such member's service retirement date.

(b) The minimum early service retirement allowance payable to a transferred Class A member or a transferred Class B member shall be equal to a minimum service retirement allowance computed in accordance with § 8-36-209(b) on the basis of the member's creditable service at the time of early retirement.