Tenn. Code Ann. § 5-8-206

Before the fifteenth of each month, each of the contracting banks shall render a statement to the county trustee, showing the balance on hand and the interest thereon due the county to the first of the month, and the county trustee shall, in the county trustee's monthly report to the county mayor, as required by § 67-5-1902(a), show the amount of the monthly balance as per bank statement, the interest to be placed by the trustee to the credit of the proper county fund.