17 CFR 140.10: The Commission.

The Commission is composed of a Chairman and four other Commissioners, not more than three of whom may be members of the same political party, who are appointed by the President, with the advice and consent of the Senate, for 5-year terms, one term ending each year. The Commission is assisted by a staff, which includes lawyers, economists, accountants, investigators and examiners, as well as administrative and clerical employees.