Market Maker A broker-dealer firm that accepts the risk of holding a particular number of shares of a particular security in order to facilitate trading in that security. Each market maker competes for customer order flow by displaying buy and sell quotations for a guaranteed number of shares. Once an order is received, the market maker immediately sells from its own inventory or seeks an offsetting order. This process takes place in mere seconds. Market Maker Spread The difference between the price at which a Market Maker is willing to buy a security and the price at which the firm is willing to sell it (the difference between the bid and ask for a given security). Since each market maker can either buy or sell a stock at any given time, the spread represents the market maker's profit on each trade.