June 30 (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.

American International Group Inc. (AIG US) fell the most in the Standard & Poor’s 500 Index, slumping 13 percent to $1.16. The insurer bailed out by the U.S. said that valuation declines on credit-default swaps sold to European banks could have a “material adverse effect” on the company’s results.

Apollo Group Inc. (APOL US) had the second-biggest gain in the S&P 500, climbing 7.8 percent to $71.12. The owner of the University of Phoenix reported third-quarter profit that beat analysts’ estimates and said it will increase its share buyback to $500 million.

Other for-profit education companies also advanced. DeVry Inc. (DV US) added 4.7 percent to $50.04. Career Education Corp. (CECO US) increased 4.7 percent to $24.89. ITT Educational Services Inc. (ESI US) rose 5.9 percent to $100.66.

Associated Banc-Corp (ASBC US) slipped 6.5 percent to $12.50, the biggest drop since June 5. The Green Bay, Wisconsin- based bank said it may report a loss in the second quarter because of increase provision related to bad loans.

Marshall & Ilsley Corp. (MI US), another Wisconsin bank, sank 3.4 percent to $4.80.

Deere & Co. (DE US) retreated 5.2 percent, the most since May 21, to $39.95. The world’s largest maker of agricultural equipment said it would eliminate 800 jobs, causing a pretax charge of $100 million that’s double the company’s prior estimate.

Electronic Arts Inc. (ERTS US) added 4.4 percent, the most since May 15, to $21.72. The world’s second-largest video-game publisher was raised to “buy” from “neutral” at Bank of America Corp., which cited an “expected upside to consensus estimates.”

Emulex Corp. (ELX US) dropped the most since Dec. 1, falling 10 percent to $9.78. The chipmaker retreated on concern that management will reject a sweetened bid from rival Broadcom Corp.

Exco Resources Inc. (XCO US) rallied the most in the Russell 1000 Index, jumping 16 percent to $12.92. The oil and gas explorer sold some assets to BG Group Plc, the U.K.’s third- largest natural-gas company, for $1.06 billion.

Geron Corp. (GERN US) surged 15 percent to $7.67, the highest price since Feb. 12. The drugmaker and GE Healthcare, a unit of General Electric Co., said they have agreed to develop products based on human embryonic stem cells for use in drug discovery, development and toxicity screening.

H&R Block Inc. (HRB US) had the steepest gain in the S&P 500, advancing 10 percent to $17.23. The biggest U.S. tax preparer said fourth-quarter profit from continuing operations was $2.09 a share, topping the average analyst estimate by 2 percent, as fees from consumer financial services increased.

International Paper Co. (IP US) gained 4.9 percent to $15.13, the fourth-steepest climb in the S&P 500. Chip Dillon, an analyst at Credit Suisse Group AG, said a potential merger of Smurfit-Stone Container Corp. and Georgia-Pacific LLC would increase International Paper’s influence in the industry.

LSI Industries Inc. (LYTS US) added 13 percent, the most since March 23, to $5.45. The lighting fixtures maker said it won a contract to upgrade the lighting system for a petroleum and convenience store retailer. The first phase of the project will bring in revenue of as much as $23 million, the company said.

Navistar International Corp. (NAV US) slumped 5.8 percent, the most since May 13, to $43.60. The fourth-largest maker of heavy trucks may eliminate 90 percent of its workforce in Canada, Reuters reported, citing the Canadian Auto Workers union.

Raser Technologies Inc. (RZ US) fell 27 percent, the steepest drop since August 2006, to $2.80. The designer of electric motors for power generation said it agreed to sell $25.5 million of stock and warrants to some institutional investors.

Schnitzer Steel Industries Inc. (SCHN US) posted the second-steepest decline in the Russell 1000 Index, dropping 12 percent to $52.86. The recycler of scrap steel reported a third- quarter loss of 5 cents a share. Analysts surveyed by Bloomberg had estimated the company earned 16 cents a share, on average.

Southern Co. (SO US) dropped 2.2 percent to $31.16, the biggest decline since April 30. The largest U.S. power producer was cut to “hold” from “buy” by Citigroup Inc.

Sunrise Senior Living Inc. (SRZ US) fell 23 percent to $1.65, the lowest price since April 28. The manager of more than 450 retirement communities was sued by HCP Inc. (HCP US) over contract claims involving 64 Sunrise-owned properties.

Vical Inc. (VICL US) rallied 23 percent, the most since May 2, to $2.70. The drugmaker said its vaccine against swine flu, also knows as the H1N1 virus, produced “robust immune responses” in mice and rabbits tested during a trial.

To contact the reporter on this story: Kayla Carrick in New York at kcarrick1@bloomberg.net.

Last Updated: June 30, 2009 16:42 EDT