The Georgia Dept. of Revenue has announced the tax overpayment and underpayment interest rates for 2019. The interest rate for interest-bearing refunds and past due taxes for the 2019 calendar year will be 8.50% accruing monthly. This is an increase from the 7.50% rate for calendar year 2018. The interest rate for refunds and past due taxes is pegged at a rate equal to the bank prime loan rate as posted by the Board of Governors of the Federal Reserve System, plus 3% to accrue monthly.