NEW YORK (TheStreet) -- Stocks jumped back into the green as volatility reigned on Wall Street Thursday. Investors had mixed reactions to the European Central Bank's announcement of its quantitative-easing program with some seeing the stimulus as a good step but others assuming the aggressive first move was a sign of tough conditions in the eurozone.

The S&P 500 added 0.56%, reversing losses suffered shortly after the market opened. The Dow Jones Industrial Average increased 0.44%, and the Nasdaq climbed 0.46%.

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Speaking in Frankfurt, President Mario Draghi announced an extended asset purchase program to buy asset-backed securities worth 60 billion euros ($69 billion) per month starting in March through to September 2016. The measures were as expected but the total amount of stimulus and timing exceeded economists' forecasts. It was previously expected the ECB's stimulus plan would entail bond purchases worth 50 billion euros ($58.2 billion) a month for at least a year.

The asset purchase program "was what the market expected but not to the extent that the ECB announced in their first go-around," said Kevin Mahn, chief investment officer at Hennion & Walsh Asset Management. "What I believe the market is now interpreting is that the situation in Europe is even worse than they anticipated and perhaps the recovery is going to take even longer."

Draghi had previously pledged to do "whatever it takes" to reinvigorate a flagging eurozone economy and move away from conditions skirting deflation.

The central bank also left its main refinancing rate unchanged at 0.05% and its marginal lending facility rate at 0.3%.

European shares surged to a seven-year high. France's CAC 40 gained 1%, Germany's DAX was up 0.81%, and London's FTSE 100 climbed 0.71%. The euro was down 0.31% to $1.15.

Meanwhile, China's central bank announced its own form of monetary easing overnight as it pledged $8 billion in capital to infuse into its financial market. Earlier this week, the world's second-largest economy reported its slowest annual GDP growth in 24 years.

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Initial jobless claims in the U.S. fell to 307,000 from a revised 317,000 a week earlier, though came in higher than expected. Economists had forecast the number of people filing for unemployment benefits for the first time to fall to 300,000.

eBay (EBAY) - Get eBay Inc. Report shares were climbing after the online auction site announced it will cut 2,400 jobs, or around 7% of its work force. Fourth-quarter profits came in slightly higher than expected. Shares were up 4%.

United Continental (UAL) - Get United Airlines Holdings, Inc. Report gained 4.9% after reporting passenger revenue more than 1% higher in its quarter, while fuel costs dropped nearly 15%. Likewise, Southwest Airlines (LUV) - Get Southwest Airlines Co. Report jumped 7% as quarterly profits beat expectations on plunging gasoline prices.

Lands' End (LE) - Get Lands' End, Inc. Report plummeted 23.2% as the retailer warned of fourth-quarter guidance below expectations, including a 7% to 9% fall in same-store sales.

SanDisk (SNDK) was lower after guiding for below-consensus revenue in its first quarter. Fourth-quarter profit did manage to beat estimates with quarterly sales up 0.6%. Shares dropped 4%.

American Express (AXP) - Get American Express Company Report beat expectations in its fourth quarter, but the credit card company also announced it will cut more than 4,000 jobs this year in line with its restructuring efforts, which will result in a $313 million charge. Shares fell 4.7%. Verizon (VZ) - Get Verizon Communications Inc. Report was 2.6% lower as quarterly profit fell slightly short of estimates, though revenue surged 7% on tablet sales.

Xilinx (XLNX) - Get Xilinx, Inc. (XLNX) Report plummeted 7% after quarterly revenue missed forecasts and as the company said current-quarter revenue was expected to drop between 2% to 6% quarter on quarter.

BlackBerryundefined surged on reports Samsung (SSNLF) is still actively pursuing a stake in the company, despite both previously denying any discussions. BlackBerry climbed 8.3%.

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--Written by Keris Alison Lahiff in New York.