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.
A-Power Energy Generation Systems Ltd. (APWR US) fell 5.8 percent to $6.18, the lowest price since Sept. 3. The Chinese power system manufacturer postponed a conference call originally scheduled for today, without giving a reason. The postponement is not due to any accounting irregularities, the company said.
Alcoa Inc. (AA US) rose 3.4 percent to $13.38 for the biggest gain in the Standard & Poor’s 500 Index. The largest U.S. aluminum producer expects global demand for the metal to grow 6.5 percent a year, doubling total consumption by 2020, the Financial Times reported, citing an interview with Chief Executive Officer Klaus Kleinfeld.
Aruba Networks Inc. (ARUN US) rose 7.8 percent to $22.98 for the biggest gain since Oct. 27. The builder of wireless networks forecast second-quarter revenue of at least $86 million, topping the $85.8 million average estimate of analysts.
Buckle Inc. (BKE US) rallied 5.1 percent to $36.98, the highest price since May 5. The U.S. casual-clothing retailer announced a special cash dividend of $2.50 a share. Third-quarter earnings were 73 cents a share, beating analysts’ estimate by 4 cents.
Cablevision Systems Corp. (CVC US) increased 6.8 percent to $30.91, a three-year high. The New York-area cable-television provider said it is exploring a spinoff of its Rainbow unit, which includes cable channels AMC, Sundance and IFC. The unit would be spun off to Cablevision’s shareholders as a “tax-free pro rata distribution,” the Bethpage, New York-based company said in a statement. The plan calls for a completion of the transaction in mid-year 2011.
Cardinal Health Inc. (CAH US) rose 6.1 percent, the most since March 2009, to $36.56. The Dublin, Ohio-based drug distributor said it plans to acquire Kinray Inc. for $1.3 billion in an all-cash transaction to expand in the northeastern U.S.
Dendreon Corp. (DNDN US) rallied 6.6 percent, the most since Sept. 1, to $38.23. The drugmaker won the backing of an advisory panel helping the U.S. government decide whether to pay for its $93,000 prostate cancer treatment. Outside advisers to the Medicare health plan said today they were confident that Dendreon’s Provenge “significantly” improves survival in men with advanced prostate cancer.
Donaldson Co. (DCI US) rose 6.2 percent to $53.66, the highest price on record in data back to 1980. The Minneapolis- based filtration-system manufacturer forecast earnings per share and sales above analysts’ estimates.
DryShips Inc. (DRYS US) jumped 7.7 percent to $5.59, the the biggest gain in a week. The Greek owner of deep-water drilling rigs and vessels that haul iron ore and coal reported that third-quarter profit rose 57 percent as revenue from drilling rigs gained.
Exelixis Inc. (EXEL US) surged 32 percent, the most in the Russell 2000 Index, to $6.23. The South San Francisco-based biotechnology company reported interim data from ovarian cancer patients treated with XL184. Tumor shrinkage was observed in 30 out of 37 patients with measurable metastatic lesions.
GameStop Corp. (GME US) fell 2.9 percent, the most since Aug. 19, to $20.40. The video-game retailer reported third-quarter sales that fell short of the average analyst estimate in a Bloomberg survey.
General Motors Co. (GM US): The automaker rose 3.6 percent to $34.19 on its first day of trading. The company raised more than $20 billion selling stock in an initial public offering that reduced the U.S. government to a minority shareholder.
Humana Inc. (HUM US) fell 2.1 percent to $56.81, the lowest price since Oct. 21. The health insurer said it expects earnings to decline in 2011 as Medicare funding cuts and the U.S. health law reduce profit.
KBR Inc. (KBR US) rose 5.2 percent, the most since June 9, to $27.57. The construction manager said it won a three-year contract with five option years to upgrade terminals at Dallas/Fort Worth International Airport.
Limited Brands Inc. (LTD US) advanced 4.4 percent to $33.26, the highest price on record in data back to 1982. The clothing retailer lifted its 2011 earnings-per-share estimate to a range of $1.82 to $1.97. On average, the analysts surveyed by Bloomberg estimated profit of $1.94. Limited Brands also said it declared a $3 a share special dividend and authorized a $200 million share repurchase program.
LTX-Credence Corp. (LTXC US) surged 32 percent to $7.87 for the second-biggest advance in the Russell 2000 Index. The maker of semiconductor testing systems agreed to a merger with rival Verigy Ltd. (VRGY US). Verigy fell 6.7 percent to $8.31.
National Oilwell Varco Inc. (NOV US) rose 4.5 percent to $61.87, a two-year high. The oilfield services company boosted its quarterly dividend to 11 cents from 10 cents.
NetApp Inc. (NTAP US) gained 7.9 percent, the most since May 27, to $53.12. The third-biggest seller of external computer-storage systems said on a conference call yesterday it expects to gain market share and is considering share buybacks.
The Sunnyvale, California-based company was also raised to a “buy” from a “hold” at Canaccord Genuity Corp.
Jabil Circuit Inc. (JBL US), whose largest customers as of Aug. 31 included NetApp, rose 6.1 percent to $14.87.
Sears Holding Corp. (SHLD US) sank 3.8 percent to $63.70, the highest price since Aug. 31. The largest U.S. department-store chain said its third-quarter loss widened as consumers remained cautious amid high levels of unemployment. Excluding some items, the loss was $1.71 a share. That’s wider than the $1.11 average estimate of four analysts compiled by Bloomberg.
SmartHeat Inc. (HEAT US) dropped 12 percent, the most since March 31, to $5. The Chinese provider of clean technology products and services said it’s offering 5 million shares to raise money for potential acquisitions.
Williams-Sonoma Inc. (WSM US) slid 10 percent, the most since January 2009, to $32.09. The gourmet-cookware retailer forecast fourth-quarter revenue may rise as little as 3 percent. Analysts had estimated a 5 percent increase.