1) Brokerage firm 
In financial services, a broker-dealer is a natural person, a company or other organization that engages in the business of trading securities for its own account or on behalf of its customers. Broker-dealers are at the heart of the securities and derivatives trading process. Although many broker-dealers are `independent` firms solely involved i.....
Any person, other than a bank, engaged in the business of buying or selling securities on its own behalf or for others. See: Dealer.
A London Stock Exchange member firm, which provides advice and dealing services to the public and which can deal on its own account.
[n] - a financial specialist who trades for his own account and so acts both as a broker and principal
noun a financial specialist who trades for his own account and so acts both as a broker and principal
FINRA firms that act as securities dealers or brokers, or perform both functions. (See broker, dealer.)