While many other industries are deeply threatened by the coronavirus outbreak, the country’s banks are still earning billions, in part because the market volatility it caused was a moneymaking opportunity for their trading divisions.

But the chaos wrought by the pandemic, which has shut down businesses across the country and put millions of people out of work, has them setting aside billions of dollars to prepare for the defaults that lie ahead.

“This isn’t a financial crisis,” Citigroup’s chief executive, Michael Corbat, said Wednesday. “It’s a public health crisis with severe economic ramifications.”

To prepare for the fallout, Citigroup and other banks are adding to their reserves — which is pinching their profits. Citi said Wednesday that it had earned $2.5 billion for the quarter, a 46 percent drop from a year earlier. It added $7 billion to its reserves, bringing its pool to nearly $21 billion.