Massachusetts - Simple Interest on Refunds after July 1, 2003

From Technical Information Release (TIR) 03-12 - Interest Rate on Overpayments and Underpayments:

The interest rate on overpayments and underpayments was the same for periods prior to July 1, 2003. An amendment to G.L. c. 62C, § 40, contained in the FY ’04 Budget, St. 2003, c. 26, § 196, reduces the interest rate paid by the Department on overpayments. Effective July 1, 2003, the interest rate on overpayments is the Federal short-term rate determined under § 6621(b) of the Internal Revenue Code, as amended and in effect for the taxable year ("Federal short-term rate") plus two percentage points, simple interest. The rate for underpayments pursuant to G.L. c. 62C, § 32, remains at the Federal short-term rate plus four percentage points, compounded daily.

Instant Interest displays the daily compounding method (DAI) in its rate table, but uses simple interest for calculations of refunds for periods subsequent to July 1, 2003.