Stocks surged Wednesday after global central banks, including the U.S. Federal Reserve, announced a coordinated effort to provide liquidity to support the global financial system and shore up the world's economy.
The Dow Jones Industrial Average was up more than 400 points at around 11 a.m. EST. The broader S&P 500 and the Nasdaq also gained more than 3 percent.
Stocks had already been buoyed before the open by China's announcement that its central bank cut the reserve requirement ratio for its commercial lenders for the first time in nearly three years to ease credit strains and shore up an economy running at its weakest pace since 2009.
The moves come amid increasing concern among policymakers worldwide that the global economy is on a slippery slope as the euro zone struggles to decisively tackle its two year debt crisis.
Investors appeared to shrug off news that ratings agency Standard & Poor's cut the ratings on many of the world's major banks, including banks in the U.S., on Tuesday.
In other U.S. economic news, a report from payrolls processor ADP showed private employers added 206,000 jobs in November.
Each month, ADP releases a report on whether private employers added any jobs in the prior month. The report is often used as a gauge heading into the government's monthly employment report, which is due out Friday.
Other data showed pending sales of existing U.S. homes surged in October by the most in nearly a year.
"There's a perfect storm of bullishness. PMI came out better than expected, plus what happened overseas, and ADP was well above consensus," said Donald Selkin, chief market strategist at National Securities in New York, with about $3 billion in assets under management.
"With this turnaround, we're right back in the same range we were a few weeks ago. For this rally to continue it will be incumbent on the data to keep coming out OK. I don't think it'll be up, up and away here, but I believe we won't break the bottom we had in October."
Reuters and The Associated Press contributed to this report.
The private sector saw an addition of 206,000 jobs in November, according to the ADP employment report. Kevin Ferry, Cronus Futures Management and CNBC's Rick Santelli break down the numbers.