A stock index representing 50 of the largest companies in Europe based on market capitalization. The stock universe used for selection is an aggregate of the 18 Dow Jones STOXX 600 Supersector indexes, which together capture about 95% of the capitalization of the major stock exchanges in 18 European countries. Each sub-index places its largest members placed on a selection list, which is then ranked by market cap to choose the STOXX 50 members. The index, first reported in 1998, is reconstituted annually, and weightings are adjusted quarterly to account for proportional changes in underlying company market caps. The Dow Jones STOXX 50 index closely resembles the Dow Jones EURO STOXX 50 in methodology and construction, with the exception that it does not limit company selection to companies that have fully transitioned to the euro currency.The index limits the weighting of any one member to 10%, but no sector limitations are applied to the index's construction. As such, banking companies dominate the STOXX 50. The index is meant to capture blue-chip companies in the region, so the average market cap is large ($70 billion euros in 2007).