Updated from 12:17 p.m. EDT

Alliance Data ( ADS) was among the NYSE's winners Thursday, as shares vaulted 24.6% after the marketing services company agreed to be acquired by the Blackstone Group for about $7.8 billion.

The deal, which also includes assumption of debt, is priced at $81.75 a share, representing a premium of 30% over Alliance Data's closing price of $62.96 on Wednesday. "By maximizing the value of their investment, this agreement is clearly in the best interests of our stockholders," Alliance Data said. "At the same time, it is business as usual for us as we continue to support our clients and partner with them to build loyal, lasting relationships with their customers." The deal is expected to close by the end of the year. Shares of Alliance closed up $15.50 to $78.46.

Ctrip.com ( CTRP) rose 8.1% after the online travel agent posted better-than-expected first-quarter results. The company earned $8.4 million, or 25 cents per American Depositary share, on revenue of $30.1 million. Analysts polled by Thomson Financial expected earnings of 24 cents a share on revenue of $28.4 million.

Looking ahead, the China-based company sees second-quarter revenue growth of about 35%. Shares closed up $5.86 to $78.07.

Shares of J.C. Penney ( JCP) rose 5.3% after the department store operator posted first-quarter earnings that topped expectations. The company earned $238 million, or $1.04 a share, on revenue of $4.35 billion. Analysts expected earnings of $1.03 a share on revenue of $4.39 billion. During the year-earlier quarter, the company earned $210 million, or 89 cents a share, on revenue of $4.22 billion.

Looking ahead, J.C. Penney now sees full-year earnings of $5.49 a share, up from an earlier forecast of $5.44 a share. Analysts project earnings of $5.49 a share. Shares closed up $4.02 to $79.74.

EnerSys ( ENS) rose 6.4% after the battery maker said that fourth-quarter results would be above analysts' expectations. The company sees earnings of 22 cents a share on revenue of about $414 million. Analysts project earnings of 18 cents a share on revenue of $394.8 million. The company plans to issue fourth-quarter results on June 13. Shares were up $1.08 to $18.01.

Shares of Caterpillar ( CAT) slipped 1.5% after an analyst cut the tractor company's rating to hold from buy. Stifel Nicolaus downgraded the stock because it believes that margins have begun to level off. The stock closed down $1.11 to $74.84.

NYSE volume leaders included Countrywide Financial ( CFC), up 98 cents to $41.31; Texas Instruments ( TXN), down 47 cents to $35.94; Micron ( MU), down 64 cents to $11.50; Motorola ( MOT), up 38 cents to $18.60; Advanced Micro Devices ( AMD), down 23 cents to $18.94; Bank of New York ( BK), down 46 cents to $40.75; Hewlett-Packard ( HPQ), down 34 cents to $44.87; and Citigroup ( C), down 11 cents to $54.80.

Nasdaq volume leaders included Sun Microsystems ( SUNW), up 18 cents to $5.30; Dell ( DELL), up 14 cents to $26.06; Intel ( INTC), up 5 cents to $22.23; Microsoft ( MSFT), down 9 cents to $30.98; Level 3 Communications ( LVLT), down 3 cents to $5.36; Applied Materials ( AMAT), down 23 cents to $18.94; Cisco ( CSCO), down 20 cents to $26.28; and Sirius Satellite Radio ( SIRI), up 3 cents to $2.72.