Ahead of the opening bell, the Federal Reserve announced plans to ease pressures in credit markets, saying it would inject cash into the markets through auction of short-term funds.
The Fed is coordinating its actions with the European Central Bank, Bank of England, Bank of Canada and the Swiss National Bank.
The Dow Jones Industrial Average was up 194.9 points, or 1.5%, at 13,629.8, with all but three of its 30 components moving higher.
"Financial shares are surging as a result of this extraordinary measure," said analysts at Action Economics.
The S&P 500 rose 27.47 points, or 1.9%, at 1,505.12, while Nasdaq 100 futures advanced 48.55 points, or 1.8%, to 2,700.9.
However, shares of Boeing Co. fell 0.3% after it was downgraded to equal-weight from overweight at Morgan Stanley.
Earlier data had the Labor Department reporting a 2.7% November rise in import prices.
Crude-oil futures rose $1.48 to $91.5 a barrel.
U.S. stocks were slammed on Tuesday after the Federal Reserve delivered a quarter-point rate cut to both the Fed funds and discount window rates. Many had expected a half-point cut to at least the discount window rate.
By Kate Gibson