A market maker is an individual or a company that quotes both a buy and a sell price in a tradable asset held in inventory, hoping to make a profit on the bid-ask spread, or turn. Market makers provide liquidity and depth to markets and profit from the difference in the bid-ask spread. They participate in the market at all times, buying securities from sellers and selling securities to buyers, and they provide liquidity, which reduces volatility and facilitates price discovery in the stock market. Market makers can be banks, brokerage companies, or individual traders. They make money by buying securities at the bid price and selling them at the ask price, which is the difference between the two prices, known as the bid-ask spread. Market makers can also make trades for their own accounts, which are known as principal trades. If market makers didnt exist, each buyer would have to wait for a seller to match their orders, which could take a long time, especially if a buyer or seller isnt willing to accept a partial fill of their order.