Tennessee Code Title 66. Property § 66-8-107

If the purchaser is a bona fide creditor by judgment, decree, or debt acknowledged by deed, and, within twenty (20) days after the sale, the purchaser makes an advance on the purchaser's bid, and credits the purchaser's debt by depositing a receipt therefor with the clerk of the court in which the judgment or decree was rendered, or, if the sale was under a deed of trust or mortgage, the purchaser acknowledges a receipt for such advance before the county clerk for registration, and causes the same to be registered in the county where the land lies, then the purchaser shall hold the property subject to redemption at the price bid and such an advance, just as if the whole sum had been bid at the time of the sale.