They were once America’s corporate titans. Beloved household names. Case studies in success.

But now, they’re increasingly looking like something else -- zombies. And their numbers are swelling.

From Boeing Co., Carnival Corp. and Delta Air Lines Inc. to Exxon Mobil Corp. and Macy’s Inc., many of the nation’s most iconic companies aren’t earning enough to cover their interest expenses (a key criterion, as most market experts define it, for zombie status).

More than 200 corporations have joined the ranks of so-called zombie firms since the onset of the pandemic, according to a Bloomberg analysis of financial data from 3,000 of the country’s largest publicly-traded companies. In fact, zombies now account for nearly a quarter of those firms. Even more stark, they’ve added almost $1 trillion of debt to their balance sheets in the span, bringing total obligations to $1.98 trillion. That’s more than the roughly $1.58 trillion zombie companies owed at the peak of the financial crisis.

The consequences for America’s economic recovery are profound. The Federal Reserve’s effort to stave off a rash of bankruptcies by purchasing corporate bonds might very well have prevented another depression. But in helping hundreds of ailing companies gain virtually unfettered access to credit markets, policy makers may inadvertently be directing the flow of capital to unproductive firms, depressing employment and growth for years to come, according to economists.

“We have come to the point that we should ask, ‘what are the unintended consequences?’” said Torsten Slok, chief economist at Apollo Global Management Inc. “The Fed, for stability reasons, decided to step in. They knew they were going to create zombies. Now the question becomes, ‘what about the companies that have been kept alive that otherwise would have gone out of business?”’