Carlo Allegri/Reuters Peter Brown, the CEO of top hedge fund Renaissance Technologies, slept 2,000 nights in his office. In an interview with Goldman Sachs, he said he valued the uninterrupted time with his colleagues. "The job is so demanding, I really don't see how I could do it otherwise." The chief executive officer of Renaissance Technologies, the secretive and massively successful hedge fund, said he has spent 2,000 nights sleeping in the office—and he has no regrets about putting in such long hours.