Mary L. Schapiro, who overhauled the Securities and Exchange Commission after the financial crisis, announced Monday that she was stepping down as chairwoman of the agency.
In recent days, the S.E.C. informed the White House and Treasury Department that Ms. Schapiro planned to leave Dec. 14, becoming the first major departure from the Obama administration's team of financial regulators. Ms. Schapiro will also relinquish her position as one of the five members of the agency's commission, the group that oversees Wall Street and the broader financial markets.
The White House announced Monday that President Obama was naming Elisse B. Walter, a commissioner at the S.E.C., as the new chairwoman. In a somewhat surprising step, Ms. Walter will not step into an interim post, but will take over the top spot for the foreseeable future.
Ms. Walter's appointment does not require Congressional approval because the Senate previously confirmed her as a commissioner. Eventually, the White House is expected to nominate another agency chief, according to a person briefed on the matter.
Ms. Schapiro's departure, which follows a bruising four-year tenure, was widely telegraphed. Ms. Schapiro, 57, has confided in staff members for more than a year that she was exhausted and hoped to leave after the November elections.
"It has been an incredibly rewarding experience to work with so many dedicated S.E.C. staff who strive every day to protect investors and ensure our markets operate with integrity," Ms. Schapiro said in a statement. "Over the past four years we have brought a record number of enforcement actions, engaged in one of the busiest rule-making periods, and gained greater authority from Congress to better fulfill our mission."