In 1991, after the successful German reunification, the solidarity surcharge ("Solidaritätszuschlag") was a means of stabilizing the federal budget.
The main purpose of was to finance the immense financial burden in the years after reunification. The solidarity surcharge is mainly payable as on income tax and corporation tax.
Levy rate of the solidarity surcharge
After its introduction, the solidarity surcharge amounted to 7.5% of the income tax or corporation tax. In 1998 the percentage was reduced to 5.5%, which is still valid today.