Bradley Saacks

Cohen also revealed the questions he asks potential hires, including "what makes them tick" and how flexible they are.

Griffin lauded Musk's entrepreneurial abilities and added that he hoped the Federal Reserve would remain independent to make necessary but unpopular decisions and shoulder the blame instead of politicians.

D.E. Shaw, started in 1988 by now-billionaire computer scientist David Shaw in New York, is remarkably secretive even for the guarded world of hedge funds.

The internal memo was titled "Citadel Widens Lead as Most Profitable Hedge Fund of All Time."