On an exchange, the member firm that is designated as the market maker (or dealer for a listed common stock). Member of a stock exchange who maintains a "fair and orderly market" in one or more securities. Only one specialist can be designated for a given stock, but dealers may be specialists for several stocks. In contrast, there can be multiple market makers in the OTC market. Major functions include executing limit orders on behalf of other exchange members for a portion of the floor broker's commission, and buying or selling for the specialist's own account to counteract temporary imbalances in supply and demand and thus prevent wide swings in stock prices.