Except as otherwise expressly provided by this chapter or by other statutes, the maximum effective rates of interest are as follows:
(1) For all transactions in which other statutes fix a maximum effective rate of interest for particular categories of creditors, lenders, or transactions, the rate so fixed;
(2) For all written contracts, including obligations issued by or on behalf of the state of Tennessee, any county, municipality, or district in the state, or any agency, authority, branch, bureau, commission, corporation, department, or instrumentality thereof, signed by the party to be charged, and not subject to subdivision (1), the applicable formula rate; and
(3) For all other transactions, ten percent (10%) per annum.