With these transactions, commonly known as "principal trades" market makers can enter and adjust quotes to buy, sell, execute and clear orders. The most common type of market maker is a brokerage house that provides purchase and sale solutions for investors in an effort to keep financial markets liquid. Market makers' rights and responsibilities vary by exchange, and by the type of financial instrument they are trading, such as equities or options. In this video you'll learn the role of a market maker.