The IRS interest rates on overpayments and underpayments for the third quarter of 2022 are one percentage point higher than in the second quarter (Rev. Rul. 2022-11). This is the second interest rate increase this year. The rates are:
5% for overpayments (4% in the case of a corporation);
2.5% for the portion of a corporate overpayment exceeding $10,000;