Nachzahlungszinsen
Interest on tax paid late after a long assessment gap.
§233a AO
Nachzahlungszinsen are interest the Finanzamt charges on additional tax set in an assessment. Under §233a AO the interest period starts 15 months after the end of the tax year — for 2025 income, on 1 April 2027 — and the rate is 0.15 % per full month (§238 Abs. 1a AO), about 1.8 % a year. Refunds earn interest on the same terms. The interest is not a penalty and is unrelated to the Verspätungszuschlag; it runs even if you filed on time but the assessment came late. For a landlord who files a first return several years after buying, the interest on the older years can be material. Interest paid on income tax is not deductible.
Last reviewed: by Yann Lephay.