The VAT authority makes a mistake: what now?

If the tax authorities make a mistake in calculating VAT, they cannot simply correct it themselves. Instead, this error must be contested via an official legal remedy (e.g. an objection or appeal).

If there is no longer an opportunity to lodge such an appeal – for example because the deadline has expired – the original tax assessment remains valid, even if it is in favour of the taxpayer.

In VAT law, it is particularly important that once a decision has been made, it cannot simply be reversed, says the Federal Supreme Court. The Federal Supreme Court emphasises that a legally binding decision cannot subsequently be ‘voluntarily’ changed or revoked by the tax authority. (Source: BGE 9C_361/2024 of 19.12.24)