The AMX index, derived from Amsterdam Midkap Index, also known as Midkap index or simply Midkap, is a stock market index composed of Dutch companies that trade on Euronext Amsterdam, formerly known as the Amsterdam Stock Exchange. The index was started in 1995. It is composed of the 25 funds that trade on the exchange and that rank 26-50 in size. The funds that rank 1-25 in size are represented in the AEX index. Wikipedia