Donald Trump’s promise to crack down on illegal immigration helped to propel his successful presidential campaign, partly thanks to the idea that undocumented low-wage workers have undercut America’s working class. But corporations that legally employ foreign workers are also expecting changes—and going to their lawyers for advice. While the ultimate effect on their business is hard to predict, law firms with immigration practices say they’ve gotten frantic calls from clients worried that the incoming administration could force costly changes to their workforces.

“It started about 10:20 on election evening,” said Michael Neifach, an immigration partner at Jackson Lewis. The theme of the questions: “What does this mean?”