The DAX stock market index is a composite index that includes the thirty of the largest companies on the Frankfurt Stock Exchange. The index weightings are calculated by the amount of shares readily available in the market instead of the total issued number of shares. This is called a free float methodology. Unlike most indexes the DAX is updated with futures prices even after the market is closed. Changes to the index are made on regular dates. Companies are capped at a weight of 10% with the top five companies making up over 43% of the index. These are Bayer, BASF, Siemens, SAP and Allianz. A company will be removed from the DAX if it falls to below 45th or lower in terms of market cap or becomes insolvent. A company will enter the DAX if it rises to the 25 th largest market cap or higher.
The DAX Index is free floating and has a base value of 1000 as of December 31, 1987.