Federal Reserve vows to support U.S. economy's long road to recovery after dire 2020

On Wall Street, which had been near unchanged ahead of the Fed's statement, stock prices ended mixed. The benchmark S&P 500 index was down about 0.5% whereas the Nasdaq Composite was up about 0.7%. Yields on U.S. Treasuries slipped and the dollar fell against a basket of currencies.

The pledge to keep monetary policy loose until the U.S. economy is back on track repeats a promise made early in the central bank's response to the coronavirus pandemic.

That response included cutting interest rates to near zero in March and making trillions of dollars in credit available to banks, financial firms, and a wide array of companies.

Powell said that while much remains uncertain, particularly the progress of the pandemic, the fiscal and monetary response has been working well so far, maintaining income support for the unemployed and limiting business failures so far.

More may be needed, he said.

"This is the biggest economic shock in living memory," Powell said. The response "has been large, forceful and very quick ... In a class by itself."