Business / Taxes / Broker-Dealer: A broker-dealer (B/D) is a license granted by the Securities and Exchange Commission (SEC) that entitles the licensee to buy and sell securities for its clients’ accounts. The firm may also act as principal, or dealer, trading securities for its own inventory. Some broker-dealers act in both capacities, depending on the circumstances of the trade or the type of security being traded. For example, your order to purchase a particular security might be filled from the firm’s inventory. That’s perfectly legal, though you must be notified that it has occurred. B/Ds range in size from independent one-person offices to large brokerage firms.
Business / Taxes / Frontrunning: If you trade stock or other investments because you know that an upcoming transaction by a third party is likely to affect the market price of the investment, you're frontrunning. Because frontrunning MORE
Business / Finance / Market Maker: Used in the context of general equities. One who maintains firm bid and offer prices in a given security by standing ready to buy or sell round lots at publicly quoted prices. See: Agent, dealer, and MORE