“Our country’s highest priority must be to address this public health crisis, providing care for the ill and limiting the further spread of the virus,” Fed Chair Jerome Powell said in a statement. “The Fed’s role is to provide as much relief and stability as we can during this period of constrained economic activity, and our actions today will help ensure that the eventual recovery is as vigorous as possible.”

The Fed is committing to buy up to $600 billion in loans from banks to medium-sized businesses that had up to 10,000 employees or $2.5 billion in revenue in 2019, in what it is calling its “Main Street” lending facility.

Under that program, the central bank will purchase 95 percent of a loan originated by a bank, which will keep the other 5 percent. The aim is to encourage the banks to lend more to mid-sized companies.

The Fed will also bolster the $350 billion that the relief package set aside for government-backed loans to small businesses by lending to banks that put up those loans as collateral.

Under an emergency facility designed to support municipalities, $500 billion will be available to buy debt from states, cities with a population over 1 million and counties with a population of more than 2 million.

The Fed is also scaling up its programs designed to buy bonds from large corporations, as well as a program to boost student loans, auto loans and credit card debt from banks, which together will now provide $850 billion in funding.

Under the latter program, the Fed will try to boost bank loans to highly indebted companies that can't borrow directly from the central bank.

As for the programs that are designed to buy debt from large corporations, the Fed is expanding the eligible companies beyond those whose debt has been deemed safe by credit ratings services. Now, if a company was designated as “investment-grade” before March 22 and has since been downgraded a notch, it could still be eligible.

The central bank is also reserving the right to buy exchange traded funds — a financial product that allows indirect investment in a group of assets — that are made up of bonds that are below investment-grade. But the “preponderance” of its ETF purchases will be investment-grade bonds.

Powell, in a webcast hosted by the Brookings Institution, suggested it would be helpful for Congress and the administration to do more to assist Americans in getting through this crisis.

“I would stress that these are lending powers, not spending powers,” he said. “In the situation we face today, many borrowers will benefit from these programs, as will the overall economy. But there will also be entities of various kinds that need direct fiscal support rather than a loan they would struggle to repay."