mWIG40TR index is calculated and disseminated since September 18, 2017, based on the value of portfolio of 40 medium size companies on the WSE Main List. Index base value was established on December 31, 2009 at the level of 2,346.14 points. Unlike mWIG20, mWIG40TR is the total return index, which means that it is calculated taking into account prices of underlying shares and dividend income. All other index construction rules are consistent with the mWIG40 index methodology.