Utilities stocks also rose on Wall Street after Berkshire Hathaway's MidAmerican Energy agreed to buy NV Energy, a Nevada-based electric and natural gas company, for $5.6 billion.

The news gave a boost to an industry sector that has been crushed this month after the rich dividend-paying stocks fell out of favor with investors.

NV Energy surged $4.34, or 23 percent, to $23.62, leading a broad advance in utility companies. Northeast Utilities rose 45 cents, or 1 percent, $42.17. Wisconsin Energy climbed 45 cents, or 1.1 percent, to $41.45.

The S&P 500 utilities index climbed 0.7 percent, its first gain in six days. It's still down 8.5 percent this month.

The number of Americans seeking unemployment aid rose last week, a sign layoffs have increased, the Labor Department said Thursday. Claims for unemployment aid rose 10,000 last week to 354,000. The government also lowered its estimate for U.S. economic growth in the first three months of the year to 2.4 percent from 2.5 percent.

Trading has been choppy on Wall Street this week as investors wrestle with the question of whether the Fed will ease its economic stimulus. Minutes released last week from the Fed's last policy meeting showed that some central bank officials favored slowing the purchases as early as next month, if the economy improves enough. The program has been a major factor supporting a rally in stocks by encouraging investors to buy riskier assets.

The Dow Jones industrial average rose 106 points Tuesday, then fell by the same amount Wednesday, leading some market watchers to ask whether the rally that has pushed the Dow and S&P 500 index to record levels may be fizzling out.

While the prospect of a change in Fed strategy is unsettling investors, ultimately, they should welcome the end of the Fed's stimulus because it means that the economy is strong enough to stand on its own two feet, JJ Kinahan, chief derivatives strategist at TD Ameritrade, said.

"It's the vote of confidence," Kinahan said. "It should mean that the overall economy is healthy."

The Dow was up 57 points, or 0.4 percent, to 15,359 points as of 1:12 p.m. Eastern Daylight Time. The S&P 500 index climbed eight points, or 0.5 percent, to 1,657. The Nasdaq composite index rose 26 points, or 0.7 percent, to 3,493.

Stock investors have had a good year so far. The Dow is 17.3 percent higher and has set record closing highs on nine days in May. The Standard & Poor's 500 index is up 16.2 percent and is on track to rise for a seventh straight monthly, its longest winning streak since 2009.

In commodities trading, oil rose half a cent to $93.59 a barrel. Gold rose $20.80, or 1.5 percent, to $1,412.20 an ounce. The dollar fell against the euro and the Japanese yen.

In government bond trading, the yield on the 10-year note was unchanged at 2.12 percent.

Among other stocks making big moves:

— Clearwire, a wireless network operator, surged 86 cents, or 24 percent, to $4.35 after satellite TV operator Dish Network raised its bid for the company to $6.9 billion.

— EMC, a data storage equipment maker, rose $1.25, or 5.3 percent, to $24.91 after the company said it will ramp up its stock buyback program and begin paying a quarterly dividend.

— Big Lots, a discount store chain, fell $3.05, or 8 percent, to $35.35 after the company reported a 21 percent drop in quarterly income and lowered its full-year revenue forecast.