Scott Friestad, currently an associate director of enforcement, and George Curtis, director of the SEC's central regional office in Denver, were appointed deputy enforcement directors by SEC Chairman Christopher Cox.

Cox also widened the authority of the enforcement division's chief counsel, giving Joan McKown additional responsibilities such as making recommendations on investigations and opening and closing cases.

Friestad, Curtis and McKown are "established leaders" with proven track records, Cox said at a news conference where he and Linda Thomsen, the agency's enforcement director, introduced the three.

Friestad and Curtis are replacing Peter Bresnan, who left in November for the private sector, and Walter Ricciardi, whose retirement was announced Monday. Like Bresnan, Ricciardi is joining a private law firm.

Friestad left private law to join the SEC in 1995 as a staff attorney. He helped lead the SEC's efforts in pursuing what the agency describes as one of the biggest insider trading cases since the Ivan Boesky scandal: a 2007 case in which 14 individuals and firms on Wall Street were charged with trading on nonpublic information from investment houses UBS and Morgan Stanley.

Curtis joined the SEC in 2006 after 30 years in private law practice. The central regional office he heads brought 49 enforcement cases during the past year, the SEC said.

McKown came to the SEC in 1986; she has been the enforcement division's chief counsel since 1993.