Use Form 8990 to calculate the amount of business interest expense you can deduct and the amount to carry forward to the next year. Current Revision Form 8990PDF Instructions for Form 8990PDF (HTML) Recent Developments Election to Substitute Adjusted Taxable Income for the Last Tax Year -- 12-MAR-2021 IRS issues final regulations and other guidance on business interest expense deduction limitation Other Items You May Find Useful All Form 8990 Revisions Basic questions and answers about the limitation on the deduction for business interest expense Rev. Proc. 2020-22 Other Current Products