May 22 (Bloomberg) -- 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.

Aeropostale Inc. (ARO US) gained 3.6 percent to $33.73, the highest price since May 11. The young-adult clothing retailer posted first-quarter earnings, excluding some items, of 49 cents a share, surpassing the average analyst estimate by 1 cent.

American International Group Inc. (AIG US) lost 5.6 percent to $1.70, the lowest price since May 13. The insurer said that Chairman and Chief Executive Officer Edward M. Liddy has informed the board of his intention to step down once it successfully concludes a search for replacements in these roles.

Archer Daniels Midland Co. (ADM US) rose 5.1 percent to $27.17, the highest price since April 6. The second-largest U.S. ethanol producer was upgraded to “hold” from “sell” by Citigroup Inc., which said a drought in Argentina will benefit American grain processors.

Aruba Networks Inc. (ARUN US) jumped 28 percent, the most since Nov. 13, to $6.59. The builder of wireless networks posted third-quarter earnings, excluding some items, of 1 cent a share, compared with the average analyst estimate of a 1 cent loss. JPMorgan & Chase Co. also upgraded Aruba to “overweight” from “neutral” after it beat estimates for two-consecutive quarters.

ATC Technology Corp. (ATAC US) fell the second most in Russell 2000 Index, dropping 19 percent to $14.09. The auto- parts supplier withdrew its 2009 earnings forecast after Honda Motor Co. said it will stop buying automatic transmissions from ATC as early as this year. Honda accounted for 10 percent of the company’s revenue last year.

Autodesk Inc. (ADSK US) rose 9.9 percent to $20.70, the highest price since Jan. 6. The biggest maker of engineering- design software forecast profit excluding some items of at least 15 cents a share in the second quarter. Analysts on average expected the company to earn 14 cents, according to a Bloomberg survey.

Black Box Corp. (BBOX US) advanced 19 percent, the most since Oct. 29, to $30.43. The operator of telephone networks in Pennsylvania posted earnings excluding some items of 91 cents a share in the fourth quarter, topping the average analyst estimate by 52 percent, according to Bloomberg data.

Cougar Biotechnology Inc. (CGRB US) rose 16 percent to $42.82 the highest price since February 2007. The developer of clinical stage cancer drugs is being pursued by Johnson & Johnson, the world’s largest health-care company. J&J said it will spend almost $1 billion to acquire Cougar and initiated a tender offer of $43 a share, a 16 percent premium to yesterday’s closing price of $36.98.

Excel Maritime Carriers Ltd. (EXM US) jumped 7 percent to $10.36, the highest price since Nov. 7. The transporter of raw commodities including iron ore and coal reported first-quarter profit excluding some items of $2.42 a share, almost five times the average analyst estimate.

LDK Solar Co. (LDK US) fell 16 percent to $7.77, the steepest decline since March 30. The Chinese maker of silicon wafers used in solar cells was reduced to “sell” from “hold” by Lazard Capital Markets, which cited the company’s “stressed leverage position, continued weak operational performance, and the likelihood that it will not be able to generate adequate margins in a continued declining polysilicon pricing environment with potential for additional write-downs.”

Nordson Corp. (NDSN US) climbed 6.9 percent to $37.69, the biggest gain since April 9. The maker of adhesive equipment posted second-quarter earnings, excluding some items, of 44 cents a share, beating the average analyst estimate by 68 percent.

Red Robin Gourmet Burgers Inc. (RRGB US) sank 17 percent, the most since November 2006, to $17.86. The restaurant operator said it expects fewer customers in the current fiscal year as consumers rein in spending and the company cuts promotions.

Salesforce.com Inc. (CRM US) fell the third most in the Standard & Poor’s 500 Index, dropping 8.8 percent to $36.15. The biggest seller of Internet-based customer management software forecast full-year revenue of $1.27 billion at most. That trailed the average analyst estimate of $1.32 billon. Citigroup Inc. cut Salesforce to “hold.”

Sears Holdings Corp. (SHLD US) posted the biggest advance in the S&P 500, surging 10 percent to $55.40. The largest U.S. department-store chain posted an unexpected first-quarter profit, helped by cuts to advertising and payroll expenses.

SkillSoft Plc (SKIL US) gained 12 percent to $8.08 for the biggest advance since March 17. The maker of employee-training software posted first-quarter profit excluding some items of 21 cents a share, topping the average estimate from analysts by 62 percent.

SunTrust Banks Inc. (STI US) fell 6 percent to $13.71, the lowest price since April 28. The Atlanta-based company was downgraded to ‘underweight” from “equal weight” by Morgan Stanley.

To contact the reporter on this story: Matt Townsend in New York at mtownsend9@bloomberg.net.

Last Updated: May 22, 2009 16:31 EDT