The OMX Nordic 40 is a stock market index for the pan-regional Nasdaq Nordic. It is a price return and capitalization-weighted index. The base date for the index is 28 December 2001, with a base value of 1000. The OMX Nordic 40 was launched on 2 October 2006 and consists of the 40 largest and most traded stocks from the four stock exchanges operated by Nasdaq Nordic: Nasdaq Stockholm, Nasdaq Copenhagen, Nasdaq Helsinki and Nasdaq Iceland. The free float market capitalization and turnover of the securities are calculated in Euro. The index is reconstituted and rebalanced semi-annually in June and December. Wikipedia