A corporation that does not file its tax return by the due date may be penalized 5% of the unpaid tax for each month or part of a month the return is late, up to a maximum of 25% of the unpaid tax. The minimum penalty for a tax return required to be filed in 2026 that is more than 60 days late is the smaller of the tax due or $525. Carta Furthermore, the IRS assesses separate penalties for late filing and late payment, and they can stack — up to a combined maximum of 47.5%. Internal Revenue Service