The Mannheim Tax Index is an indicator for the effective tax levels of companies, as taxation is deemed to be an important location factor. More precisely, it benchmarks countries and regions from a tax perspective, taking into account taxes on profits and invested capital as well as the most important regulations in determining the taxable base. In doing so, it provides a comprehensive picture of taxation by following two general strands: the taxation of domestic companies along with their shareholders and cross-border corporate investments. Analysing the taxation of companies is a traditional way of comparing the fiscal attractiveness of regions competing with one another internationally. It concentrates on the tax rates borne by mobile capital and mobile companies.

The Mannheim Tax Index calculates effective tax rates for 27 EU countries as well as the United Kingdom, Switzerland, Norway, North Macedonia, Turkey, the USA, Canada and Japan for the period from 1998 to 2024. In addition to the company level, the shareholder level and cross-border bilateral investments are also covered.