Securities market participants (United States)
Securities market participants in the United States include corporations and governments issuing securities, persons and corporations buying and selling a security, the broker-dealers and exchanges which facilitate such trading, banks which safe keep assets, and regulators who monitor the markets' activities. Investors buy and sell through broker-dealers and have their assets retained by either their executing broker-dealer, a custodian bank or a prime broker.
Source: Wikipedia — Securities market participants (United States) (CC BY-SA 4.0)