Richard Walker, director of enforcement for the U.S. Securities and Exchange Commission, is leaving the regulator for private practice.

Walker has not yet accepted a new position and will remain at the SEC for a short period to assist with the transition to a new chairman. Walker became head of enforcement in 1998 after serving as the commission’s General Counsel.

He headed the commission’s largest division and directed its nationwide enforcement effort. He spearheaded its attack against earnings management and other financial reporting abuses, established its Internet enforcement program, and led the commission’s efforts to secure more criminal prosecutions for violations of the federal securities laws.

Walker is credited as the driving force behind the SEC’s financial fraud cases, involving W.R. Grace, Livent, Cendant, McKesson HBOC, Microstrategy, Sunbeam, and Arthur Andersen, and the 1999 landmark auditor independence case against PricewaterhouseCoopers.

Acting Chairman Laura Unger said, “America’s investors have benefited greatly from Dick Walker’s presence at the SEC. He has served the commission masterfully in three demanding positions, bringing enormous intellect, judgment and grace to each. He has been a leader of the staff, an ambassador of the agency, and a respected colleague and friend.”

The North American Securities Administrators Association’s president Deborah Bortner said, “Dick Walker brought a passion and a commitment to his work that truly inspired others.”