The Treasury Department said Thursday that it was asking approximately 150 publicly traded firms to repay nearly $600 million in loans they received from the federal program designed to help small businesses cover expenses and payroll amid the coronavirus pandemic.

The change comes after the initial $349 billion in emergency funding for small businesses ran out last week, with critics pointing to a loophole that allowed large companies to receive loans by applying through multiple subsidiaries with under 500 employees. A Wall Street Journal analysis found that 24 of the publicly traded companies that took loans employed more than 500 people, while a third earned over $100 million in annual revenue in their last fiscal year.

“The intent of this money was not for big, public companies that have access to capital,” Secretary of the Treasury Steven Mnuchin said at a news briefing Tuesday.

Several public companies, including burger chain Shake Shack, which received $10 million, and Ruth’s Chris Steak House, which received $20 million, have already said they will return the loans.