Shares of the following companies had unusual moves in U.S. trading. Stock symbols are in parentheses, and prices are as of 4 p.m. in New York.
Barnes & Noble Inc. (BKS US) surged 52 percent to $20.75 for the biggest increase in the Russell 2000 Index and the stock’s best ever gain. 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 US) rose 24 percent, the most since October 2008, to $18.77. The maker of a female-sterilization method boosted its full-year sales forecast.
Demand Media Inc. (DMD US) rallied 15 percent to $8.31, the highest price since Sept. 27. 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.
Expedia Inc. (EXPE US) gained 5.8 percent to $42.65, the highest price since at least 2005. The online-travel company rallied for a second day after saying on April 26 that first-quarter profit and revenue topped analysts’ estimates, driven by growth in the Hotels.com unit.
Gen-Probe Inc. (GPRO US) climbed 19 percent, the most since April 2003, to $81.55. The developer of testing for sexually transmitted disease agreed to be bought by Hologic Inc. (HOLX US) for about $3.7 billion in cash. Hologic slipped 9.9 percent to $19.12.
Harman International Industries Inc. (HAR US) increased 4.9 percent, the most since Dec. 20, to $49.58. 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 US) declined 8.1 percent, the most in the S&P 500, to $80.68. 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 US) surged 30 percent, the most since it went public in February 2011, to $3.83. 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.
NYSE Euronext (NYX US) had the second-biggest decline in the S&P 500, retreating 4.9 percent to $25.75. 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 US) dropped 7.5 percent, the most since Feb. 6, to $51.57. 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.
Sunoco Inc. (SUN US) climbed 20 percent to $49.29 for the biggest advance in the S&P 500. The Philadelphia-based refiner 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.
TeleCommunication Systems Inc. (TSYS US) slipped 8.5 percent to $1.93, the lowest price since June 2003. The Annapolis, Maryland-based network applications company was cut to underperform from sector perform at RBC Capital Markets.
Tenneco Inc. (TEN US) fell 15 percent, the most since Aug. 8, to $30.83. 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 US) slipped 12 percent, the most since March 2009, to $47.64. The largest maker of credit-card terminals was cut to sell from hold by Deutsche Bank AG.
Warner Chilcott Plc (WCRX US) gained 16 percent, the most since August 2009, to $21.81. 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.