Dresser-Rand, Robert Half, Threshold, Zoltek: U.S. Equity Movers

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.

Staffing companies advanced as an unexpected drop in the U.S. jobless rate fueled optimism over a rebound in the labor market. Robert Half International Inc. (RHI US) climbed 5.3 percent to $29.60. Manpower Inc. (MAN US) rose 5.2 percent to $46.81. On Assignment Inc. (ASGN US) gained 7.7 percent to $12.19.

American Superconductor Corp. (AMSC US) rallied 12 percent to $5.78, the highest price since Sept. 15. The wind-turbine part maker suing its former largest customer announced its quarterly earnings release date. The company last year failed to file its annual report on time because it was reviewing Chinese revenue.

Constant Contact Inc. (CTCT US) advanced 16 percent, the most since October 2007, to $30.22. The provider of web-based e-mail marketing services reported profit in the fourth quarter of 27 cents a share, excluding some items, beating the average analyst estimate of 24 cents.

Con-way Inc. (CNW US) lost 6.9 percent, the most since Sept. 21, to $30.71. The U.S. trucking company had fourth-quarter earnings that fell short of the average analyst projection, data compiled by Bloomberg show.

Dresser-Rand Group Inc. (DRC US) slumped 6.9 percent, the most since Aug. 8, to $49.21. The maker of equipment for oil and natural gas industries reduced its forecast for 2012 operating income to as low as $360 million.

Edwards Lifesciences Corp. (EW US) fell 11 percent, the most in the Standard & Poor’s 500 Index, to $71.54. The maker of products to treat late-stage cardiovascular disease was lowered to “market perform” from “outperform” at Wells Fargo & Co.

Genworth Financial Inc. (GNW US) rose the most in the S&P 500, rallying 14 percent to $9.17. The mortgage guarantor and life insurer swung to a fourth-quarter profit on a decline in new claims tied to delinquent borrowers.

Gilead Sciences Inc. (GILD US) climbed 11 percent to $54.70 for the third-biggest gain in the S&P 500. The drugmaker that acquired Pharmasset Inc. last month for its experimental hepatitis C treatments said one of the therapies produced positive clinical trial results.

Other hepatitis C drug developers fell. Idenix Pharmaceuticals Inc. (IDIX US) dropped 11 percent to $11.68. Achillion Pharmaceuticals Inc. (ACHN US) lost 5.2 percent to $11.73.

Infinera Corp. (INFN US) advanced 15 percent, the most since July 2010, to $8.38. The maker of high-speed computer networking equipment reported a fourth-quarter loss excluding some items of 6 cents a share, narrower than the 13-cent loss estimated by analysts on average.

Intermec Inc. (IN US) fell 7.3 percent, the most since Nov. 9, to $8.10. The maker of hand-held scanners reported a fourth-quarter profit of 13 cents a share, missing the average analyst estimate by 29 percent, according to data compiled by Bloomberg.

International Game Technology (IGT US) slipped 4.5 percent, the third-most in the S&P 500, to $15.59. The world’s biggest maker of slot machines fell after a Florida House panel postponed consideration of a proposal to allow casino gambling, saying it won’t consider the legislation this year.

Modine Manufacturing Co. (MOD US) slid 11 percent, the most since Aug. 8, to $10. The auto-parts maker cut its full-year forecast, saying it expects to earn 75 cents a share at most. Analysts, on average, estimated 92 cents, according to a Bloomberg survey.

PC Connection Inc. (PCCC US) tumbled 19 percent, the most since December 2008, to $10.31. The computer seller reported fourth-quarter profit of 28 cents a share, missing the 36 cents estimated by Raymond James Financial Inc.

PerkinElmer Inc. (PKI US) advanced 6.2 percent, the most since Oct. 27, to $26.23. The provider of equipment for genetic screening and drug research forecast 2012 earnings excluding some items of at least $1.98 a share, topping the average analyst estimate of $1.91 in a Bloomberg survey.

Smart Technologies Inc. (SMT US) tumbled 12 percent, the most since May 19, to $3.67. The producer of interactive whiteboards used in classrooms reduced its full-year earnings forecast after third-quarter profit missed analysts’ estimates.

STR Holdings Inc. (STRI US) fell 20 percent, the second-most in the Russell 2000 Index, to $9.03. The solar-panel parts maker said its fourth-quarter adjusted loss was no more than 4 cents a share, compared with an earlier forecast for a profit of at least 9 cents a share. Analysts project the company would have a 10-cent profit per share, data compiled by Bloomberg show.

THQ Inc. (THQI US) plunged 30 percent to 53 cents, the lowest price since 1995. The publisher of wrestling and martial arts video games reported third-quarter profit of 35 cents a share, missing the average analyst estimate by 53 percent, according to data compiled by Bloomberg.

Threshold Pharmaceuticals Inc. (THLD US) soared 132 percent, the biggest gain since it went public in February 2005, to $2.99. German drugmaker Merck KGaA (MRK GR) agreed to pay as much as $525 million for the right to jointly develop and sell a drug for cancer.

Trimble Navigation Ltd. (TRMB US) jumped 5.6 percent to $50.83, the highest price since April 27. The maker of global-positioning products said it expects profit of at least 61 cents excluding some items in the first quarter. That’s higher than the average analyst estimate of 58 cents in a Bloomberg survey.

Tyson Foods Inc. (TSN US) gained 4.1 percent, the most since Aug. 9, to $19.38. The largest U.S. meat processor reported first-quarter earnings of 42 cents a share, beating the average analyst estimate of 34 cents.

Urban Outfitters Inc. (URBN US) climbed 4.7 percent, the most since Dec. 13, to $27.69. The clothing retailer named Ted Marlow chief executive officer. Marlow was brand president of the Urban Outfitters division for nine years before leaving the company in 2010.

Wynn Resorts Ltd. (WYNN US) slipped 4.8 percent, the most since Nov. 21, to $114.98. Wynn Macau Ltd.’s full-year profit missed analysts’ estimates as the casino company benefited less than its competitor, Sands China Ltd., from surging gambling revenue in the former Portuguese colony.

Zoltek Cos. (ZOLT US) rose the most in the Russell 2000 Index, rallying 38 percent to $13.11. The maker of carbon fibers for windmill blades said it earned 28 cents a share in the first quarter, compared with the average analyst estimate of 7 cents.

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