AEX index

AEX index

AEX index performance between 1982 and 2012
Foundation	1983
Operator	Euronext
Constituents	up to 25
Type	Large cap
Market cap	€490.85 billion (Begin March 2015)
Weighting method	Capitalization-weighted
Related indices	AMX index, AScX index
Website	www.aex.nl

The AEX index, derived from Amsterdam Exchange index, is a composed of Dutch companies that trade on , formerly known as the Amsterdam Stock Exchange. Started in 1983, the index is composed of a maximum of 25 of the most actively traded securities on the exchange. It is one of the main national indices of the stock exchange group Euronext alongside Brussels' BEL20, Paris's CAC 40 and Lisbon's PSI-20.

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 is 703.18, reached on 5 September 2000 at the height of the dot-com bubble. The index value more than halved over the following three years before recovering in line with most global financial markets.

The AEX index enjoyed its second 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.

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 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 some other European benchmark equity indices (such as the ), if a company has more than one class of shares traded on the exchange, only the most actively traded of these will be accepted into the AEX. If a company or companies are removed from the index due to , acquisition or another reason, no replacements are made until the next review date.