The AEX index, derived from Amsterdam Exchange index, is a stock market index composed of Dutch companies that trade on Euronext Amsterdam, formerly known as the Amsterdam Stock Exchange. Started in 1983, the index is composed of a maximum of 25 of the most frequently traded securities on the exchange. It is one of the main national indices of the stock exchange group Euronext alongside Euronext Brussels' BEL20, Euronext Dublin's ISEQ 20, Euronext Lisbon's PSI-20, the Oslo Bors OBX Index, and Euronext Paris's CAC 40. History The AEX started from a base level of 100 index points on 3 January 1983 (a corresponding value of 45.378 is used for historic comparisons due to the adoption of the Euro). The index's peak to date was set on 26th October 2021 816.91 After the dot-com bubble in 1999, the index value more than halved over the following three years before recovering in line with most global financial markets. The AEX index dealt with its second largest one-day loss on March 12, 2020, when the index closed down almost 11% during the coronavirus pandemic. The AEX index enjoyed its third largest one-day loss on September 29, 2008, when the index closed down almost 9%. The decade between 1998 and 2008 has been bad for the AEX index, as it has been the worst performing stock index except for the OMX Iceland 15. The preceding years were a lot better compared to the rest of the world. Annual Returns The following table shows the annual development of the AEX index since 1983. Rules Selection As of 2011, the AEX index composition is reviewed four times a year - a full "annual" review in March and interim "quarterly" reviews in June, September and December. Any changes made as a result of the reviews take effect on the third Friday of the month. Previously reviews were held in March and September only. Prior to 2008, index changes were made only annually in March. At the main March review date, the 23 companies listed on Euronext Amsterdam's regulated market with the highest share turnover (in Euros) over the previous year are admitted to the index. Of the companies ranked between 24th and 27th, a further two are selected with preference given to existing constituents of the index. Companies which have fewer than 25% of shares considered free float on Euronext Amsterdam are, however, ineligible for inclusion. Unlike