The stock market surged again on Thursday, putting the Dow Jones industrial average on track for its best week since 2011.
Investors plowed money back into stocks following a slump the week before, encouraged by a 4 percent jump in the price of crude oil and Pfizer's $16 billion deal to buy the drugmaker Hospira.
The Dow Jones industrial average jumped more than 200 points, its third big gain this week. The Dow is now up about 700 points, or 4 percent, so far this week.
That's a far cry from the week before, when the blue-chip index stumbled nearly 3 percent.
“We've been returning to more normal volatility and this week is just the most recent example of that,” said Gabriela Santos, a global market strategist with JPMorgan Funds.
The Dow Jones industrial average rose 211.86 points, or 1.2 percent, to 17,884.88. The Standard & Poor's 500 index added 21.01 points, or 1 percent, to 2,062.52. The Nasdaq composite rose 48.39 points, or 1 percent, to 4,765.10.
The gains put the Dow and S&P 500 back into the black for 2015.
Health care stocks and energy companies had some of the biggest gains.
Drug giant Pfizer said it would buy Hospira, a maker of injectable drugs, for $90 a share in cash. The deal is the first by Pfizer since it walked away from a merger with AstraZeneca last year. Like many other large drug companies, Pfizer is trying to generate more sales as its blockbuster drugs go generic. Hospira soared $22.84, or 35 percent, to $87.62 and Pfizer rose 92 cents, or 3 percent, to $32.99.
Oil also had a wild day.
Benchmark U.S. crude rose $2.03 to settle at $50.48 a barrel on the New York Mercantile Exchange, continuing a volatile ride that has lasted for several weeks. On Wednesday, oil plunged $4.60, or 8.7 percent, to settle at $48.45 a barrel the day before after the U.S. government reported an increase in crude inventories last week.
Few investors believe the turbulence in oil trading will end any time soon. While data earlier this week showed U.S. production is slowing, this week's crude oil inventory levels tell a different story.
“We're starting to see some production shifts, but it's happening slowly,” Santos said. “Oil is going to keep making these big swings until something is done to deal with all this oversupply.”
Brent crude, a benchmark for international oils, rose $2.50 to $56.66 a barrel in London.
U.S. stocks shrugged off more bad news in Europe. Greek stocks dropped as tensions between the country's new left-wing government and the European Central Bank intensified.
Greece's new left-wing government is insisting it will stick to its anti-austerity agenda, hours after the European Central Bank tightened the screws on Athens by withdrawing a key borrowing option for the country's banks.
Greek stocks dropped 3 percent on the news. European stocks closed mostly flat, after being down more sharply earlier in the trading day.
“The decision by the ECB to no longer accept Greek bonds as collateral may be aimed at piling the pressure on Greece to request an extension of its current bailout beyond February 28, but it is has also raised the risk that Greece could be forced into a default,” said Jane Foley, an analyst at Rabobank International.
In other markets, U.S. government bond prices fell. The yield on the 10-year Treasury note rose to 1.81 percent.
Gold fell $1.80 to $1,262.70 an ounce, silver fell 20 cents to $17.20 an ounce and copper was flat at $2.60 a pound.
In other energy commodities:
— Wholesale gasoline rose 4.3 cents to close at $1.525 a gallon.
— Heating oil rose 3.9 cents to close at $1.806 a gallon.
— Natural gas fell 6.2 cents to close at $2.600 per 1,000 cubic feet.