Gensler was a key reformer and perhaps the most aggressive Wall Street regulator during the Obama administration. He’s shown here at left at a Financial Stability Oversight Council meeting in 2010 with Treasury Secretary Tim Geithner (from second left), Federal Reserve Chairman Ben Bernanke and Sheila Bair, chairman of the Federal Deposit Insurance Corp.

From left to right, Gary Gensler, Chairman of the Commodity Futures Trading Commission, Secretary of Treasury Tim Geithner, Chairman of the Federal Reserve Ben Bernanke, and Chairman of the FDIC Sheila Bair at the Financial Stability Oversight Council’s (FSOC) first meeting at the US Dept. of the Treasury in Washington, Friday, Oct. 1, 2010.(AP Photo/Pablo Martinez Monsivais)