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 the wealth management firm he leads.

Having joined Renaissance Technologies two decades ago—being promoted to executive vice president in 2003 and being named a co-CEO in 2010—Brown has set an unusual precedent for the company and stuck with it.

He told podcast host Raj Mahajan, global head of systematic client franchise at Goldman Sachs, that new hires at the company are “almost exclusively” from a non-finance background.

With so much riding on Wall Streets whims, many of Renaissance’s competitors might find that strange, but for Brown—who worked on the earliest iterations of AI large language models like ChatGPT—it makes perfect sense.

Renaissance Technologies uses quantitative models derived from mathematical and statistical analysis to inform its investment decisions.

“We find it much easier to teach mathematicians about the markets than it is to teach mathematics and programming to people who know about the markets,” Brown said. “Everything we do we figured out for ourselves, and I really like it that way. Unlike some of our competitors, we try to avoid hiring people that have been at other financial firms.”