Amsterdam Stock Exchange (AEX) .AS Definition

Founded in 1602, along with the creation of the Dutch East India Company (VOC), the Amsterdam Stock Exchange is considered the oldest, still functioning stock exchange in the world.

The need for a bank grew with the growth of European trade and with the need to offer financiers a way to profit in this commerce. The Dutch East India Company is one earliest business to compete for the exports from the spice and slave trade. It was a joint-stock company and would offer shares to investors who would bankroll the voyages. Financiers required a safe and regulated place where buy and sell shares of these early global enterprises.

Before the AEX, many regions and towns had independent systems of asset valuation and trade regulation which operated much like stock exchanges, but the AEX was the first official stock exchange as we know it.

Over its centuries-long history, the Amsterdam stock exchange has gone through several ownership changes and governance structures.

Looking to recent history, in 1997 the Amsterdam Stock Exchange and the European Options Exchange (EOE) merged, and its blue-chip index was renamed AEX, for "Amsterdam EXchange."

In September 2000, the Amsterdam Stock Exchange merged with the Brussels Stock Exchange and the Paris Stock Exchange to form Euronext Amsterdam. Euronext is Europe's largest cash equities market. For some time fell under the umbrella of NYSE Euronext, which operated several exchanges, including the New York Stock Exchange, the Liffe in London, and NYSE Arca Options. In 2014, Euronext was spun off to become an independent entity once again. As of 2017, Euronext was the sixth largest combined stock exchange by market cap.

Euronext Amsterdam's three broad equity indexes are the blue-chip AEX, mid-cap AMX, and small-cap AScX. By far, the most traded and influential index is the AEX, which began in 1983 and is composed of the 25 most frequently traded Dutch companies which trade on Euronext Amsterdam. These companies include international businesses such as Unilever, ING Group, Philips, and Royal Dutch Shell. It is one of the leading national indices of the stock exchange group Euronext alongside Brussels' BEL 20, Paris's CAC 40 and Germany's DAX.

Review of the composition of the AEX index is done quarterly each year, with a comprehensive review conducted in March and interim reviews in June, September, and December. Any changes made to the index as a result of these examinations take effect on the third Friday of the month. Before 2008, index changes were made only once annually in March.

The AEX is a market capitalization-weighted index, with initial index weightings of any one company capped at 15%. The index weights are calculated concerning the closing prices of the relevant companies on March 1. During quarterly reviews, weightings after adjustment are left as close as possible to those of the previous day and are not re-capped.