Millionaire investor Peter Brown has slept in his office 2,000 times

But if they called and offered you a pay rise, you might nod off again with a smile on your face.

That’s what Peter Brown, CEO of investment management firm Renaissance Technologies, was banking on when he dialed a subordinate’s number at one o’clock in the morning.

Speaking on Goldman Sachs’s Exchanges podcast, Brown—who is worth $100 million according to Forbes—said he was working late with a colleague when they came across a problem neither of them could solve.

“It was around 1 a.m. and I picked up the phone to call him,” Brown recalled. “[My colleague] said to me ‘Wait, you can’t call this guy in the middle of the night, he doesn’t make enough money.’ So I said: ‘Fine, how about this? I’ll call him, I’ll tell him we’re going to give him a raise, and then ask the question.’ So that’s what we did.”

Brown himself confesses to sending emails at 2 a.m. and barely sleeping. But the legendary investor, who trained as a language technology expert at IBM before joining the Jim Simons-founded firm, said he gets his job done thanks to an unusual tactic: sleeping in the office.

The hedge funder confirmed in last week’s episode of Exchanges that it was “true” he had spent almost 2,000 nights sleeping in his Long Island office.

“For me productivity wise, it’s really fantastic to spend nearly 80 straight hours each week, with no interruptions except sleep, thinking about work,” he said.

After the grueling ritual, Brown said he spends three “normal” days at home—his wife Margaret Hamburg, the former Commissioner of the U.S. Food and Drug Administration, works in Washington, D.C.

“Of course I really miss my family,” the father of two said. “But the freedom to concentrate non-stop while surrounded by my colleagues is hugely valuable. The job is so demanding, I really don’t see how I could do it otherwise.”

Brown was also sentimental about why he works so hard when he’s away from his family.

“My experience has been that when a husband and a wife work in two different towns, the husband commutes,” he added. “Psychologically if I’m going to be away from my family, I have to work. I sleep in my office when I’m in Long Island.”

Aside from working into the early hours, Brown has established another unorthodox practice at…