If a customer’s tax return for any of the years 2016 to 2017 to 2019 to 2020 is amended after 3 March 2021 and they’re no longer entitled to the amount they originally claimed for either their fourth or fifth (or both) SEISS grant, they must repay the amount they were overpaid by HMRC.

We’re writing to customers whose entitlement to those grants has been reduced by more than £100, asking them to repay the overpaid amount. If a customer has been overpaid on their fifth SEISS grant, we’ll also compare the reference year (2018 to 2019 or 2019 to 2020) turnover figure they entered when claiming this, with the declared turnover figure on their latest tax return. If the figures don’t match and this means they received an 80% grant when they should have received a 30% grant, the difference will be included in the total overpaid amount they will be asked to repay in the letter.