The AEX is a benchmark equities index of Euronext Amsterdam. It lists the top 25 most actively traded stocks of Dutch companies that trade on Euronext Amsterdam and is the key indicator of the health of the Dutch economy, as well as of the exchange itself.

    Its total market capitalisation was around €253 billion as at December 2011.

    Criteria for inclusion

    Companies are selected according to their market capitalisation, adjusted for their free float, provided at least 25% of their shares are a free float. The weightings are capped at 15%.

    The top 23 companies on Euronext Amsterdam by share turnover in euros are automatically included on the AEX. The last two places are given to two of the four companies ranked 24 to 27 on the Amsterdam Euronext, selected according to various performance criteria.

    A composition of the AEX is reviewed annually every March, with further quarterly reviews in June, September and December although no adjustments will be made unless a company has left the index. If companies are removed from the AEX between reviews, because of split-offs, takeovers, delisting or some reason, the empty places will not be allocated until the next review and will be filled by the highest-ranked companies in the AMX being moved up.