That surpasses the $15 billion John Paulson generated betting against subprime mortgages in 2007. All together, the top 20 hedge funds generated $22.4 billion in post-fee profits, Citadel included.

The secret to Griffin’s success, if you ask him, is simple: Workers returned to the Citadel offices.

Fortune CEO Alan Murray sat down with Griffin and New York City Mayor Eric Adams two weeks ago as part of an interview for the Partnership for New York City. “At that meeting, Griffin gave what he said was an important reason for his 2023 success: His employees were all back in the office full-time,” Murray wrote in his CEO Daily newsletter on Tuesday. 

Many a suit nodded their heads in agreement, per Murray’s account. Of course, there could also be other reasons contributing to Citadel’s success. Chairman of LCH Investments Rick Sopher said in a statement that the strong gains multi-strategy hedge funds like Citadel have made in recent years “reflect their increasing dominance in strategies which do not depend on rising asset prices, and their substantial size.”

But this isn’t the first time Griffin has boasted about the benefits of a return to in-person work. 

“If you are early in your career, you are making a grave mistake not being back at work,” Griffin told Bloomberg’s Erik Schatzker in 2021. Citing the importance of managerial and interpersonal experience in developing one’s career, Griffin added that he was concerned that the loss of opportunities for young professionals would “cost us dearly over the decades to come.”

He brought the Citadel employees back to the office full-time in June 2021. “Having everybody back together has been really powerful in driving forward our business,” Griffin said at the time. 

Return to office fever has infected many CEOs and executives in the financial sector. Morgan Stanley CEO James Gorman recently said coming into the office was “not an employee choice.” Goldman Sachs’ David Solomon was one of the initial finance CEOs to push for a return to office, as early as a full year ago, only to be met with opposition. Even today, not all employees are showing up. Rich Handler, CEO of investment bank Jefferies also joined the work-in-the-office team.

“If you want a job, stay remote all the time and be efficient in a very limited way,” Handler in an Instagram comment on a @WallStreetConfessions post. “If you want a career, engage with the rest of us in the office and use wfh only when smart, flexibility is essential, mental health calls, and life balance needs help.”

“This is a time to treat Wall Street the way it was treated for generations,” Mike Mayo, a bank analyst at Wells Fargo, told Fortune in July. 

Despite the insistence that being in person at the office is good for business, research shows that working from home is just as good as in-person work: Many workers spend their extra “commute” time working, and their productivity may be higher. Hybrid workers, who have the best of both worlds, are more loyal and more connected and productive. 

But if the CEOs have it their way, a return to traditional ways of work is on the horizon. As Murray pointed out, “If you are part of the New York financial community and haven’t gotten your return-to-office notice yet—stay tuned!”