The New York Times with the details:
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.
President Obama wasted little time naming a replacement: Elisse B. Walter, who was already serving as an SEC commissioner. Here's how the Wall Street Journal summed up the departing chairwoman's legacy:
A career regulator, Ms. Schapiro is credited by current and former SEC officials with steadying the agency after its failure to spot the Madoff fraud. Her likeable personality and experience in top regulatory roles helped to repair the SEC's battered image, protect its powers during a big rewrite of financial regulations and boost employee morale.
Schapiro's departure was far from a surprise, but it does mark the likely start of a larger batch of transitions within the Obama administration. Unlike many that will follow, however, Walter's appointment doesn't require congressional approval, so it won't be accompanied by the typical partisan bickering and congressional hurdles that we can all look forward to with many of the others.