The statute of limitations is the period in which the authorities can go back to investigate a tax liability. This is normally the same period in which a taxpayer can go back to request a tax credit.
The statute of limitations in Germany is 4 years. This start point of this period is the 31 December of the year in which the annual VAT return was filed. In any case, this period cannot start being counted later than 3 years from the time VAT became due. If no annual VAT return was filed, the statute of limitation is 7 years.
There is an extended period of 10 years in case of tax evasion.