The Warsaw Stock Exchange Index (WIG) is the oldest stock exchange index, calculated at the first market session. The basic index values are calculated on the basis of the prices of shares of all stock exchange companies with at least 10% of freely-traded shares with a value equivalent to 1 mln euro. WIG is a total-return index, and the revenues from both dividends and subscription rights are taken into account in its calculation. The initial level of the index on 16 IV 1991 was 1000 points.