Revenue at companies with flexible work-from-home policies grew four times faster than those with in-person requirements, according to a new study by Scoop Technologies and Boston Consulting Group.

The findings, from a survey that analyzed 556 public companies that employ a collective 26.5 million people across 20 sectors, represent a significant blow for proponents — and owners — of office space.

Firms that allow their employees to either work entirely from home or pick the days they come in increased sales 21% between 2020 and 2022, per the survey, first reported by Bloomberg. Companies with hybrid or full-time office policies saw revenue growth of just 5%.

Among the companies that do require office work, those that allowed just a few days in-person saw sales go up at twice the rate of those that demanded workers come into the office full-time.

“This starts to be a more compelling case for CFOs and CEOs to not be five days in the office,” Scoop co-founder and CEO Rob Sadow told Bloomberg. “People ask if revenue growth is the best proxy — you could also look at shareholder returns. There is no perfect answer, but we felt this was a first step in the right direction.”

The revenue growth in the survey was normalized against average industry growth rates, so the findings weren't skewed by higher-performing sectors.

One possible explanation is that flexible workplace policies allow companies to hire from a broader range of people, and to recruit more quickly.

At Allstate, for example, remote-friendly jobs receive double the number of applications, Fortune reported. A total of 84% of its new employees in the U.S. in the last year don’t live near a company office. The insurance giant slashed its real estate footprint by over 50% alongside its embrace of remote work.

The remote work debate has raged for years now, as workers, employers and office landlords have debated the best way to drive productivity. While office owners have stressed that in-office work is the best way to do business, employees have often balked at returning to their desks in the same way they did before the pandemic. Some sectors, like law firms, have taken a more hardline approach and mandated that their workers come back to the office.

Tech firms gave workers a lot of flexibility, but have in recent months brought workers back, with companies like Amazon, Facebook and Google mandating multiple office days per week this year. More than 3 million workers are expected to be under new office attendance mandates this year, according to JLL.

Those mandates have yet to result in a large bump in office occupancy, and office markets in places like New York continue to be affected by the rise of remote work. The availability rate in Manhattan, the country’s largest office market, was at 17.8% in October, according to Colliers.