Registered professionals, firms, or agencies that buy and sell securities on behalf of clients, including large stock brokerages. Broker-Dealers execute securities sales and purchases on behalf of clients, provide investment advice to customers, supply liquidity through market-making activities,  publish investment research, raising capital for companies, and operate market platforms. Broker-Dealers must be registered with the SEC and are closely regulated. Several types of investment crowdfunding and general solicitation activities require that the issuer work with a registered broker-dealer.