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:
Rules that limit the deduction of losses from passive activities to income from other passive activities. Passive activities include investment rental operations or businesses in which you do not materially participate.