U.S. stocks rose Thursday as the Dow Jones Industrial Average grew 2.8% to 10173, the S&P 500 gained 3% to 1087 and the Nasdaq Composite rose 2.8% to 2219. Among the companies whose shares are actively trading in the after-hours session are ArcSight Inc. (ARST), Finisar Corp. (FNSR), National Semiconductor Corp. (NSM). ArcSight's fiscal fourth-quarter earnings soared on strong sales that beat its optimistic outlook. Shares in the provider of compliance and security software were up 8.5% at $21.50 in after-hours trading Thursday as it also gave an upbeat outlook. Finisar swung to a fiscal fourth-quarter profit on better-than-expected revenue growth and improved margins, while year-earlier results were stung by write-downs. The fiber-optic equipment maker also gave a strong sales view for the current quarter. Shares rose 3.9% in after-hours trading to $14.80. National Semiconductor swung to a fiscal fourth-quarter profit following $116.1 million in prior-year charges while demand increased for analog products from the wireless handset and industrial markets. Results easily topped Wall Street's expectations, helping shares rise 1.5% to $13.73 in after-hours trading. Regular Session Movers: BP PLC (BP, $32.78, +$3.58, +12.26%) said it sees no justification for the collapse in its share price, even as it admitted the cost of the Gulf of Mexico oil spill has risen to $1.43 billion and U.S. politicians pushed for the company to assume even greater liabilities. In a press release that followed a steep decline in Wednesday trading, the oil giant said it is a strong company and is "generating significant additional cash flow." Stocks of other companies tied most closely to the disaster were also climbing, including Anadarko Petroleum Co. (APC, $39.15, +$4.32, +12.40%), Transocean Ltd. (RIG, $44.27, +$1.69, +3.97%), Cameron International Corp. (CAM, $36.39, +$2.26, +6.62%) and Halliburton Co. (HAL, $24.22, +$1.66, +7.36%). Meanwhile, J.P. Morgan upgraded Baker Hughes Inc. (BHI, $42.42, +$4.07, +10.61%) to overweight from neutral and Weatherford International Ltd. (WFT, $13.64, +$0.87, +6.81%) to neutral from underweight, but cut Ensco PLC (ESV, $38.17, +$1.56, +4.26%) to neutral from overweight as the analysts said large-cap oil-services companies should come out on top during the deepwater drilling moratorium, as the impact will be "fairly modest." While J.P. Morgan cut its earnings views for the services group by an average of 7% to reflect the moratorium, it kept its 2011 estimates intact. Other services companies that were rising Thursday included Schlumberger Ltd. (SLB, $59.17, +$3.70, +6.67%), Pride International Inc. (PDE, $24.12, +$1.52, +6.73%), Diamond Offshore Drilling Inc. (DO, $61.35, +$4.25, +7.44%), Noble Corp. (NE, $29.45, +$1.87, +6.78%) and Rowan Cos. (RDC, $24.28, +$1.37, +5.98%). Old Republic International Corp. (ORI, $12.80, -$0.11, -0.85%) has agreed to buy PMA Capital Corp. (PMACA, $6.89, +$0.78, +12.77%) for $228 million in stock as the struggling insurer looks to build its general-insurance business. Old Republic does most of its business in property and casualty coverage but has been slammed by weakness in its mortgage and general insurance operations. Shareholders of PMA, a holding company that provides workers' compensation and other commercial property and casualty lines of insurance and fee-based services, will receive 0.55 of new issued Old Republic shares for each PMA shares, valuing PMA at $7.10, a 16% premium to Wednesday's close. A-Power Energy Generation Systems Ltd. (APWR, $9.13, +$1.76, +23.88%) fiscal first-quarter profit soared on investments and warrants, while the company posted surging sales in its wind-turbine business, reporting record company-wide results for the period. The Chinese alternative-energy company, which provides power-generation systems, also boosted its 2010 forecast. Software company Synopsys Inc. (SNPS, $21.26, +$0.20, +0.95%) agreed to acquire Internet and provider of semiconductor intellectual-property company Virage Logic Corp. (VIRL, $11.96, +$2.59, +27.59%) for $315 million, which is expected to strengthen Synopsys' system-on-chip development goals. Synopsys will pay $12 a share, a 28% premium to Wednesday's closing price. The deal will cost Synopsys $289 million after accounting for the cash on Virage Logic's books. Men's Wearhouse Inc.'s (MW, $22.20, +$3.53, +18.91%) fiscal first-quarter profit surged as the retailer's sales and margins grew, while occupancy costs declined. The retailer, which operates stores for men in the U.S. and Canada under the Men's Wearhouse, Moores and K&G names, topped its March earnings forecast and beat Wall Street's revenue estimate, while also adding that reports it was considering opening a women's wear store were "inaccurate." American Capital Ltd. (ACAS, $5.20, +$0.44, +9.24%) amended terms of its debt-exchange offers and extended the acceptance deadline by two weeks as the business-development company continues efforts to restructure its debt. The company said Wednesday night it has entered into a lock-up agreement in which holders of a combined 43% of $963 million of notes agreed to tender them in support of the offer. Meanwhile, the minimum support level needed for the deal to proceed has been cut to 51% from 85%. American Eagle Outfitters Inc. (AEO, $12.68, +$0.47, +3.85%) raised its quarterly dividend 10% to 11 cents a share, saying the increase reflects its strong cash generation and commitment to enhancing shareholder value. The teen retailer also said it has repurchased 5.9 million shares for about $96 million this year, leaving 24.1 million shares remaining under its current authorization. ARM Holdings PLC (ARMH, $12.30, +$0.59, +5.04%) surged in London trading and its American depositary shares followed suit in New York as traders suggested that Apple Inc. (AAPL, $250.51, +$7.31, +3.01%) may be preparing to make a bid for the U.K.-based chip design company. Panmure Gordon analyst Nick James, for one, is skeptical, saying the only reason Apple would buy it would be to deny everybody else access to ARM's processor cores. James said the real driver of ARM's stock price strength is growing bullishness on prospects for the 'tablet' market, a massive opportunity for ARM. ARM declined to comment. C.R. Bard Inc. (BCR, $79.84, +$2.11, +2.71%) approved a stock-buyback plan that allows the maker of medical products to repurchase up to $500 million of its shares. The new program is in addition to the $107 million remaining under the April 2009 authorization. Cereplast Inc. (CERP, $3.44, -$1.00, -22.52%) plans to sell $7.5 million of stock and warrants to institutional investors, using proceeds to expand the product line of environmentally friendly bio-plastic resins for the sustainable plastics maker. CF Industries Holdings Inc. (CF, $64.28, +$5.31, +9.00%) is an attractive risk/reward option because of its stock drop and long-term potential of potash, Morgan Stanley analysts wrote in resuming coverage on the fertilizer producer. The firm put an overweight rating on the shares and said it continues "to prefer the potash sector over nitrogen due to potash's more attractive industry structure and superior growth prospects." Other fertilizer stocks rallied including, Agrium Inc. (AGU, $53.29, +$2.47, +4.86%), Potash Corp of Saskatchewan Inc. (POT, $100.31, +$4.59, +4.80%) and Intrepid Potash Inc. (IPI, $22.49, +$1.42, +6.74%). Chubb Corp. (CB, $51.39, +$1.69, +3.40%) announced plans to buy back an additional 14 million shares as the property-and-casulty insurer believes its share prices are at an "attractive" level for purchase. (MORE TO FOLLOW) Dow Jones Newswires June 10, 2010 17:11 ET (21:11 GMT)