Barnes & Noble, Humana, Sunoco: U.S. Equity Movers

Shares of the following companies are having unusual moves in U.S. trading. Stock symbols are in parentheses, and prices are as of 10:50 a.m. in New York.

Barnes & Noble Inc. (BKS) surged 66 percent to $22.68 for the biggest increase in the Russell 2000 Index. A new subsidiary that combines the bookseller’s Nook digital reader and college businesses will receive a $300 million investment from Microsoft Corp. (MSFT US).

Conceptus Inc. (CPTS) rose 21 percent to $18.34 for the biggest intraday gain since October 2008. The maker of a female- sterilization method boosted its full-year sales forecast.

Demand Media Inc. (DMD) rallied 23 percent to $8.90 after reaching $9.51, the highest intraday price since Aug. 15. A deal by Thomas H. Lee Partners to take private the operator of websites eHow.com and LiveStrong.com for $1.2 billion fell apart, AllThingsD said, without saying where it got the information.

Gen-Probe Inc. (GPRO) climbed 19 percent, the most intraday since April 2011, to $81.85. The developer of testing for sexually transmitted disease agreed to be bought by Hologic Inc. (HOLX) for about $3.7 billion in cash. Hologic slipped 8.9 percent to $19.34.

Harman International Industries Inc. (HAR) increased 11 percent to $52.42 and jumped 12 percent earlier, the most intraday since Oct. 21. The maker of audio equipment for cars and homes reported third-quarter earnings excluding some items of 74 cents a share, exceeding the average analyst estimate of 67 cents.

Humana Inc. (HUM) declined 6.2 percent, the most in the Standard & Poor’s 500 Index, to $82.36. The second-biggest provider of U.S.-backed Medicare insurance said first-quarter profit declined as premiums failed to keep up with rising medical costs.

Imperial Holdings Inc. (IFT) surged 33 percent to $3.91 after rallying as much as 40 percent, the most intraday since it went public in February 2011. The specialty finance company agreed to pay an $8 million penalty to resolve fraud allegations related to its involvement in making misrepresentations on life insurance applications, the Department of Justice said.

Merck & Co. (MRK) rose the most in the Dow Jones Industrial Average, climbing 2 percent to $39.23. The drugmaker’s subsidiaries won a patent-infringement case against Sigma Pharmaceuticals Plc (SIP AU) over the importing of asthma drugs from Poland to the U.K.

Sunoco Inc. (SUN) climbed 19 percent to $48.81 for the biggest advance in the S&P 500. The Philadelphia-based refinery agreed to be acquired for $5.3 billion in shares and cash by Energy Transfer Partners LP (ETP US), which is adding oil transportation and distribution assets.

NYSE Euronext (NYX) had the second-biggest decline in the S&P 500, retreating 4.7 percent to $25.80. The largest U.S. exchange operator reported a 44 percent decline in first-quarter profit, as expenses related to its failed merger with Deutsche Boerse AG combined with a slowdown in trading.

Sohu.com Inc. (SOHU) dropped 8.1 percent to $51.27 after sinking 10 percent earlier, the most intraday since Feb. 6. The operator of China’s third-biggest online video site forecast lower-than-expected growth in revenue this quarter as an economic slowdown weakened online advertising sales.

Tenneco Inc. (TEN) fell 9.6 percent to $33.63 after erasing 11 percent earlier, the most intraday since Oct. 28. The world’s largest maker of vehicle-exhaust systems reported first- quarter earnings and revenue that fell short of the average analyst estimates.

VeriFone Systems Inc. (PAY) slipped 9 percent to $49.54 after sliding 11 percent earlier, the most intraday since May 12. The largest maker of credit-card terminals was cut to sell from hold by Deutsche Bank AG.

Warner Chilcott Plc (WCRX) gained 17 percent to $21.97 after jumping as much as 24 percent, the most intraday since August 2009. The maker of dermatology and women’s health drugs said it is exploring a sale of the company and is in talks with potential buyers.

To contact the reporter on this story: Lu Wang in New York at lwang8@bloomberg.net.

To contact the editor responsible for this story: Nick Baker at nbaker7@bloomberg.net