A member of a stock exchange whose purpose is to maintain an orderly market in the securities that are assigned to him. To accomplish this task, the specialist may need to buy or sell for his own account when either buyers or sellers are scarce. The specialist also will act as the broker for other brokers. If a broker has an order to buy 100 shares of a stock at $52, but it is trading at $50, then the order is left with the specialist, who will execute it, if it trades up to $52.