U.S. bankruptcy filings have slowed nearly to a halt, but they're expected to pick up next year, led by companies that piled on debt to survive this year's pandemic and election-related volatility.

"The march of the zombies will come to a head," said Howard Steel, partner in the financial restructuring group at law firm Goodwin Procter LLP, who expects bankruptcy filings to accelerate in the second quarter of 2021. "Many of the companies that are surviving by issuing new debt to fund operating losses and interest payments will not be able to survive for the long run in a protracted pandemic."

Almost 200 corporations have joined the ranks of so-called "zombie firms" since the onset of the pandemic, according to a Bloomberg analysis. Many of the country's most iconic companies aren't earning enough to cover interest expenses.