And the central bank has promised another resource — the Main Street Business Lending Program — that officials say will help businesses that are too big to qualify for small business loans but too small to have easy access to capital markets.

That was unveiled March 23, but the Fed has yet to detail how it will work or how much money will stand behind it. Eric Rosengren, president of the Federal Reserve Bank of Boston, told Bloomberg on Wednesday that it was in the design phase and that a rollout could be a “another couple” of weeks away.

The coronavirus response law instructs Mr. Mnuchin to ask the Fed chair, Jerome H. Powell, if he would consider a program that provided financing to banks to make cheap loans to companies with 500 to 10,000 employees. The Main Street program could check that box.

Do big corporations get a lot of help?

Big companies with solid balance sheets benefit in several ways.

The Fed’s emergency lending has an overarching goal: It is supposed to help markets function smoothly. Corporate debt has been rocked by the coronavirus spread. Companies found themselves in need of cash as restaurants closed, movie theaters went dark and tourism essentially dried up. But because they had become riskier and markets were in meltdown, fewer investors were willing to buy their bonds.

The Fed has unveiled several programs to help. One supports a type of short-term funding known as commercial paper, and another that buys company debt secondhand. A third program buys newly issued debt or makes direct loans to corporations.

The programs go well beyond what the central bank did for companies in 2008, but all focus on investment-grade debt. They mostly leave companies with shakier prospects out in the cold. Doing so avoids rewarding firms that have piled on debt while buying back shares or making acquisitions, but also deepens the rift between stable companies and their riskier counterparts.

Could the Fed help my local government?

The Fed has unveiled a couple of programs that are helping municipal bond markets by allowing banks to use some types of local debt as collateral for cheap loans.