Companies that made it through the pandemic in one piece now have a major new problem: more than a quarter of their employees may leave.

What's happening: Workers have had more than a year to reconsider work-life balance or career paths, and as the world opens back up, many of them will give their two weeks' noticeand make those changes they’ve been dreaming about.

“The great resignation” is what economists are dubbing it.

• Surveys show anywhere from 25% to upwards of 40% of workers are thinking about quitting their jobs.
• "I don't envy the challenge that human resources faces right now," says Anthony Klotz, an associate professor of management at Texas A&M University.

Anumber of colliding trends are driving the resignation boom, experts say.

• University of Michigan economist Betsey Stevenson tells Axios, "People have had a little more space to ask themselves, 'Is this really what I want to be doing?'" So some are deciding they want to work fewer hours or with more flexibility to create more time for family or hobbies.
• Others are considering switching careers entirely.
• A cruise ship staffer trained and pivoted to work in a data center because the pandemic showed her the volatility of her industry.
• An insurance broker and her restaurant manager husband both left their jobs to start a landscaping company because they realized during the pandemic that they wanted to spend more time outside.
• Some are quitting because their bosses won't let them work from home post-pandemic. Others are leaving because they miss their offices, but their companies are now hybrid or all-remote.
• "A lot of people who want to go back are finding that the office that they come back to is not the office they left behind," Klotz says.

There's not much firms can do to hold onto employees who want to switch fields. But human resources may be able to retain some workers by offering as flexibility as possible, says Cathy Moy, chief people officer at BDO USA, a financial services company.

But, but, but: The big churn could ultimately be good for workers and employers.

• There are now a record 9.3 million open jobs in America, Axios' Felix Salmon reports. And people can still rely on unemployment insurance so they're not desperate to nab the first job offer that comes along, Stevenson says.
• "Hopefully we’ll see a lot more people in 2022 employed and stable because they're in jobs they actually like," she says.