Trading firms that trade for their own account and risk (proprietary traders) play a crucial role in the smooth functioning of the stock exchange. They are supervised by the Netherlands Authority for the Financial Markets (AFM) and the Dutch Central Bank (DNB) and are united in the Dutch trade association for proprietary trading firms, the Association of Proprietary Traders (APT). Their roles, duties, and powers are defined by law.

The APT was founded in 2003 as a successor to the Association of Market Makers on the European Options Exchange, which was established in 1984.

APT currently has 23 members. Almost all members are located in Amsterdam, around Beursplein 5, the Zuidas business district, and near other financial technology companies. All members are represented on the Members' Council, chaired by Jurjen Kruisinga (Cross Options).