Jim Millstein, co-chairman of Guggenheim Securities, is sounding the alarm against adding leverage to firms hit hard by the coronavirus pandemic, especially in the housing market, where firms have taken on excessive debt.

“You’ve had tremendous volatility in credit markets, and in mortgage assets,” Millstein said in a Bloomberg Television interview. “Margin calls on people who are levered with short-term debt are at high risk.”

Millstein, who was the restructuring chief of the U.S. Treasury Department in the wake of the 2008 financial crisis, said he expects a wave of restructurings in the energy, travel and leisure industries.

With half of the economy shut down, “that’s going to have contagion effects to the rest of the economy,” he said. Rising unemployment and consumers forced to stay home will keep them from going to showrooms to buy cars, as one example, he said.

Millstein, who’s expecting a deep recession, said that the U.S. government would have to start making investments in firms to stimulate the economy. A rising number of companies won’t have access to the Federal Reserve’s commercial lending facilities due to ratings downgrades, he said, adding that the Fed’s loan capacity may ultimately be large as $3 trillion.

S&P Global Ratings and Moody’s Investors Service have been downgrading U.S. firms at the fastest pace in more than a decade. Half of outstanding investment-grade debt is one notch above junk, Millstein said.

“As those downgrades occur, you’re creating a series of corporations who will not have access to the Fed facility,” he said. And even if debt is available, “leverage is not a cure to negative free cash flow.”