Arch Coal, Caterpillar, NYSE Euronext: 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.

Solar stocks rallied after explosions at two nuclear reactors in Japan triggered speculation that renewable energy plants may win favor. Jefferies Group Inc. said solar and wind power equipment producers will benefit from the country’s rebuilding program. MEMC Electronic Materials Inc. (WFR US) had the biggest gain in the Standard and Poor’s 500 Index, climbing 11 percent to $13.37. First Solar Inc. (FSLR US) rose 5.1 percent to $146.91. Trina Solar Ltd. (TSL US) gained 7.3 percent to $26. LDK Solar Co. (LDK US) advanced 8.8 percent to $11.58. Power-One Inc. (PWER US) climbed 13 percent to $8.20.

Power plant operator Entergy Corp. (ETR US) declined 4.9 percent to $70.09 for the third-biggest retreat in the S&P 500, after being cut to “market perform” from “outperform” by BMO Capital Markets.

General Electric Co. (GE US), the world’s biggest maker of power-generation equipment and designer of one of the reactors at a plant north of Tokyo that exploded, declined 2.2 percent to $19.92. Babcock & Wilcox Co. (BWC US), which makes nuclear components to support U.S. defense programs, slumped 9 percent to $31.28.

Shaw Group Inc. (SHAW US) fell the most in the Russell 1000 Index, sinking 9.2 percent to $34.87. JPMorgan Chase & Co. said the construction company with a nuclear unit may be affected by the earthquake.

Uranium stocks slumped on demand concerns after the Japan nuclear power accidents. Denison Mines Corp. (DNN US) plunged 22 percent to $2.55. Uranium Energy Corp. (UEC US) erased 19 percent to $3.92. Uranium Resources Inc. (URRE US) dropped 25 percent to $1.75. Cameco Corp. (CCJ US) tumbled 13 percent to $32.62. Ur-Energy Inc. (URG US) declined 27 percent to $1.82. USEC Inc. (USU US) slipped 11 percent to $4.59. Paladin Energy Ltd. (PALAF US) dropped 21 percent to $3.78.

Coal producers rallied on expectations that the shutdown of Japanese nuclear reactors will lead to more coal use. Peabody Energy Corp. (BTU US) added 3.4 percent to $65.27. Arch Coal Inc. (ACI US) advanced 1.2 percent to $32.88. Alpha Natural Resources Inc. (ANR US) gained 3.6 percent to $52.93. Cloud Peak Energy Inc. (CLD US) climbed 2.7 percent to $20.62.

Aflac Inc. (AFL US) slipped 3 percent, the most since Nov. 26, to $53.90. The world’s largest seller of supplemental health insurance reiterated that operating earnings growth in 2011 will be at the low end of an 8 percent to 12 percent forecast. The Columbus, Georgia-based company said sales in Japan will be minimally affected by the earthquake and that offices in Japan are fully operational with no casualties.

American Superconductor Corp. (AMSC US) dropped 4.5 percent, the most since Dec. 16, to $23.19. The maker of wind-turbine components and transmission lines said it agreed to buy Switch Engineering Oy of Finland for 190 million euros ($265 million).

Caterpillar Inc. (CAT US) added 2.1 percent to $102.10 for the biggest gain in the Dow Jones Industrial Average. The world’s largest construction equipment maker may be among the U.S. companies to benefit as Japan rebuilds after the world’s strongest earthquake since 2004 hit last week, according to analysts at Susquehanna Financial Group and Sterne Agee & Leach Inc.

Corinthian Colleges, Inc. (COCO US) rose 8.2 percent, the most since Dec. 30, to $4.91. The for-profit operator of North American colleges and trade schools said an increase in tuition prices may ensure that the company will remain in compliance with a federal rule that no more than 90 percent of revenue can come from federal student grants and loans.

Las Vegas Sands Corp. (LVS US) dropped 3.6 percent to $38.62, the lowest price since Oct. 21. The casino company with most of its business in Asia was cut to “hold” from buy” at Jefferies & Co. The 12-month price estimate is $45.00 a share.

Lawson Software Inc. (LWSN US) rose 6 percent to $12.24, the highest price since March 2002. The maker of business software received an unsolicited $11.25 a share cash buyout offer from Infor and Golden Gate Capital. The deal values the company at $1.84 billion according to Bloomberg calculations.

Lubrizol Corp. (LZ US) soared 28 percent to $134.68, the highest intraday price since at least 1980. Warren Buffett’s Berkshire Hathaway Inc. agreed to buy the world’s largest producer of lubricant additives for about $9 billion in the cash-flush investor’s second-biggest acquisition in the past five years.

NYSE Euronext (NYX US) rose 3.6 percent, the most since Feb. 9, to $36.55. Nasdaq OMX Group Inc. (NDAQ US) is in talks with lenders about funding a hostile bid for the owner of the New York Stock Exchange, two people with knowledge of the matter said. Nasdaq declined 3 percent $26.38.

Pfizer Inc. (PFE US) climbed 1.8 percent to $19.81, the second-biggest gain in the Dow Jones Industrial Average. The world’s biggest drugmaker is considering spinning off some units, shrinking its sales base by 40 percent, Sanford C. Bernstein & Co. said in a note, citing Chief Executive Officer Ian Read.

Star Scientific Inc. (CIGX US) jumped the most in the Russell 2000 Index, rallying 18 percent to $3.48. The tobacco company appealing the loss of an intellectual-property lawsuit brought against Reynolds American Inc. (RAI US) climbed for a second day after saying a U.S. government reexamination has affirmed two patents central to the case.