The IRS has announced that the interest rates applicable to overpayments and underpayments of federal taxes are the same in the fourth quarter of 2020 as they were in the third quarter of 2020 (Rev. Rul. 2020-18). The rates are:
Payments made to a separated or divorced spouse as required by a decree or agreement. Qualifying payments are deductible by the payor and taxable to the payee.