In general, individuals who buy and sell securities professionally must register with the appropriate SRO, meet certain qualification requirements, and comply with rules of conduct adopted by that SRO.
The broker-dealer firms for which they work must, in turn, register with the SEC and comply with the agency's rules relating to such matters as financial condition and supervision of individual account executives.
In addition, broker-dealer firms must also comply with the rules of any exchange of which they are a member and, usually, with the rules of the NASD. The SEC can deny registration to securities firms and, in some cases, may impose sanctions against a firm and/or individuals in a firm for violation of federal securities laws (such as, manipulation of the market price of a stock, misappropriation of customer funds or securities, or other violations).
The SEC polices the securities industry by conducting inspections and working in conjunction with the securities exchanges, the NASD, and state securities commissions.