Market Maker
A firm or individual that continuously quotes buy and sell prices for a security, providing liquidity to the market.
What is Market Maker?
A market maker is a broker-dealer firm or individual that stands ready to buy and sell a particular security at publicly quoted prices, earning a profit from the bid-ask spread. By continuously quoting two-sided prices, market makers provide liquidity — ensuring that investors can trade without waiting for a matching counterparty. On NASDAQ, market makers are required for each listed stock. On the NYSE, designated market makers (DMMs) perform this role at the physical exchange. Major market-making firms include Citadel Securities, Virtu Financial, and Susquehanna International Group. Market makers are distinct from brokers, who only execute trades for clients, and are also distinct from retail traders.
Example
When an investor places a market order to buy 100 shares of Apple at the best available price, a market maker like Citadel Securities may sell those shares from its own inventory at the posted ask price of, say, $185.10 — even if no natural seller exists at that moment — profiting from the bid-ask spread.
Source: Investopedia — Market Maker