The top accountant in the Securities and Exchange Commission's enforcement branch is leaving for a private sector job next month, in what could herald a wave of departures from the embattled agency.

The SEC said Tuesday that Susan Markel, chief accountant in the agency's division of enforcement, is taking a job in the corporate investigations practice of AlixPartners LLP, a turnaround consulting firm.

Her departure comes as President-elect Barack Obama's SEC chairman-designate, Mary Schapiro, is likely to face tremendous pressure to bring sweeping changes to the agency, said James Cox, a Duke University law professor and securities law expert.

The SEC has come under fire for failing to detect signs that major Wall Street firms were in trouble. It also has been criticized for ignoring allegations brought to SEC staff about Wall Street money manager Bernard Madoff's businesses. Madoff has been accused of engaging in a massive fraud that may end up costing investors $50 billion.

With the SEC under intense scrutiny from the incoming administration and lawmakers a Capitol Hill, more high-level staff changes could be in the works, Cox said.

For current staffers, it is often better "to leave on your own accord than to face the awkwardness of being asked to leave," he said.

Markel has been at the SEC since 1994, working on the agency's inquiries into Xerox Corp., Cendant, WorldCom and Cardinal Health Inc.

Linda Chatman Thomsen, director of the SEC's Division of Enforcement, praised Markel saying in a statement that "her instincts are superb and her investigative abilities are unparalleled"

Obama has promised a tougher regulatory and enforcement approach after he takes office on Jan. 20.

"Instead of appointing people with disdain for regulation, I will ensure that our regulatory agencies are led by individuals who are ready and willing to enforce the law," Obama said earlier this month.