The Federal Reserve unanimously decided to cut interest rates by half-a-percentage point — a large amount — in an emergency response to the spread of coronavirus and its impact on the economy.

Why it matters: The last time the Fed announced an interest rate cut outside a regularly scheduled meeting was in the midst of the financial crisis. The rare move shows the Fed's effort to stem any impact the coronavirus poses to the record-long economic recovery.

Between the lines: Market-watchers say a rate cut is not an adequate response to the coronavirus outbreak, though it could "soften collateral damage to spending and confidence," as the Wall Street Journal puts it.

"Certainly, rate cuts will not help re-stock emptying grocery shelves. Monetary policy is hopeless when supply simply cannot feed demand," Seema Shah, chief strategist at asset management firm Principal Global Investors, said in a statement.

How it's playing: Stocks fell slightly after Powell's comments, giving back some of Monday's big gains. As of Tuesday morning, the S&P was teetering back into correction territory, or 10% below its record high.

What they're saying: "We do recognize a rate cut won't reduce rate of infection. We don't think we have all the answers," Fed chairman Jerome Powell told reporters on Tuesday.

"The ultimate solutions to this challenge will come from others, particularly health professionals. We can and will do our part, however, to keep the U.S. economy strong."

Driving the news: The sudden move Tuesday came on the heels of exhortations on Twitter by President Trump for the Fed to act — and after the Fed telegraphed on Friday that it would move soon to react to the rapidly unspooling coronavirus outbreak.