Jay Clayton is Trump's SEC pick, where he'll serve on the Financial Stability Oversight Council that monitors risk in the financial system.

Flashback: As a partner at Sullivan & Cromwell, Clayton broker deals for large banks and their risky mortgage activity in 2008, including:

• Barclays Capital's acquisition of Lehman Brothers' assets
• Bear Stearns' sale of Morgan Chase
• the U.S. Treasury Department's capital investment in Goldman Sachs

Why it matters: Trump has said he will crack down on Wall Street, adding "I'm not going to let Wall Street get away with murder. Wall Street has caused tremendous problems for us."

But he also profited off the foreclosure crisis, bragging in a Trump University promo: "I've always made a FORTUNE in FORECLOSURES, and YOU WILL TOO."