A "market maker" is a firm (bank, brokerage company) that stands ready to buy and sell a particular commodity on a regular and continuous basis at a quoted price. In foreign exchange trading, the market maker sells to and buys from its clients. They provide liquidity to the market, being on the other side of trades when there are short-term buy-and-sell-side imbalances in customer orders, and attempt to prevent excess volatility. Proponents of the official market making system claim market makers add to the liquidity and depth of the market by taking a short or long position for a time, thus assuming some risk, in return for hopefully making a small profit. Market makers are required to maintain two-sided markets during exchange hours and are obligated to buy and sell at their displayed bids and offers.