RSA 336:1 Rate of Interest.

I. The annual rate of interest in all business transactions in which interest is paid or secured, unless otherwise agreed upon in writing, shall equal 10 percent. No consumer credit transaction, as defined in RSA 358-K:1, V, shall be subject to this paragraph. If agreed upon in writing, interest on business transactions may include charging other than simple interest.
II. The annual simple rate of interest on judgments, including prejudgment interest, shall be a rate determined by the state treasurer as the prevailing discount rate of interest on 26-week United States Treasury bills at the last auction thereof preceding the last day of September in each year, plus 2 percentage points, rounded to the nearest tenth of a percentage point. On or before the first day of December in