Perella Weinberg told staff primarily in New York and London that its plans will be delayed. The investment bank may seek to bring more workers back in October, depending on the trajectory of the virus, a person familiar with the matter said, asking not to be identified discussing internal decisions. Perella Weinberg previously sought a September return.

Jefferies is planning for a more general office return on Oct. 4., after preparing for what it called the future of work model at the bank in September.

“Under current conditions we want to move cautiously and not fully implement those plans while the risks are too high,” Jefferies Chief Executive Officer Richard Handler and President Brian Friedman said in a memo to staff seen by Bloomberg News. “That timeline will give us the ability to carefully assess the progression of the virus and its variants as we move through the end of the summer.”

Jefferies had a dozen more colleagues globally contract the virus, though no cases were severe, the executives said. It has already required that employees wishing to return to the office be vaccinated.

Perella Weinberg announced its decision on Monday during a town hall hosted by Chief Executive Officer Peter Weinberg and Co-Presidents Andrew Bednar and Dietrich Becker. Bednar told hundreds of global employees that a five-day, 15-hour-a-day week in the office is from the “last chapter,” as executives have been saying for months that flexibility will be part of the future.

Other Wall Street firms have delayed return-to-office plans. BlackRock Inc. said last week that it would wait an extra month, and will look to open its doors to more employees in October. Wells Fargo & Co. has made a similar move.

Perella Weinberg, which listed publicly this year in a merger with a special purpose acquisition vehicle, has more employees returning to offices in Houston, Los Angeles, San Francisco and Chicago. Meanwhile, just a fraction of New York and London workers is returning, the person said.

A Perella Weinberg spokeswoman didn’t return a message seeking comment.