The PX index is the official index of the Prague Stock Exchange. The index was calculated for the first time on March 20, 2006 when it replaced the PX50 and PX-D indices. The index took over the historical values of the PX50 index. The starting date was April 5, 1994 with a base of 1000 points. As of 24 Sep 2012, composition fully reflects the Free Float of members due to methodology changes.