April 21 (Reuters) - U.S. stocks were flat on Monday ahead of key earnings releases as investors found few reasons to push indexes sharply higher following a strong rally last week. The Dow Jones industrial average was up 0.07 percent at 16,420.13, the S&P 500 was up 0.08 percent at 1,866.29 and the Nasdaq Composite was up 0.09 percent at 4,099.101.
** HALLIBURTON CO, $62.82, +3.15 pct
The world's No. 2 oilfield services company, reported better-than-expected quarterly results, helped by robust drilling activity in Russia, Saudi Arabia and Angola.
** HASBRO INC, $55.26, +1.19 pct
The toymaker reported a quarterly profit, compared with a year-ago loss, helped by strong demand for its toys for girls. Sales of girls' toys such as My Little Pony and Nerf Rebelle increased 21 percent to $138.7 million in the first quarter ended March 30.
** SAREPTA THERAPEUTICS INC, $35.0661, +43.71 pct
** PROSENSA HOLDING NV, $5.23, +3.16 pct
Sarepta said it would start new trials to revive the chance of approval for its experimental muscle disorder drug after the U.S. Food and Drug Administration advised the company to submit new safety and efficacy data.
Prosensa makes drisapersen, a competing drug that failed a late-stage trial in September 2012.
** SEARS HOMETOWN AND OUTLET STORES INC, $24.06, +7.70 pct
Edward Lampert, the beneficial owner of the home appliance retailer, filed with regulators on Thursday to disclose a purchase of 173,574 shares of the company's stock at $20.62 each.
** PLUG POWER, $7.16, -2.19 pct
** BALLARD POWER SYSTEMS INC, $3.995, +5.69 pct
The Canadian fuel cell maker said on Monday it had agreed to form a joint venture with South Korea's Hyundai Hysco Co Ltd , a steel supplier to Hyundai Motor, to develop and sell hydrogen fuel cells in Asia.
Shares of Ballard, one of the biggest clients Plug Power, were also up.
** GASLOG LTD, $26.87, -4.17 pct
Analysts at brokerage firm Jefferies & Co downgraded the operator of liquefied natural gas carrier to "hold" as they expect the near-term liquefied natural gas shipping outlook to remain weak.
** AASTROM BIOSCIENCES INC, $4.643, +31.90 pct
The company said it agreed to acquire French drugmaker Sanofi SA's cell therapy and regenerative medicine business for $6.5 million, which will give it global commercial rights to three marketed autologous cell therapy products.
Revenues of the three products - Carticel, Epicel and MACI - were $44 million in 2013.
Aastrom will also acquire global manufacturing and production centers located in the United States and Denmark.
** YINGLI GREEN ENERGY HOLD CO LTD, $4.2, +1.45 pct
The Chinese solar panel maker said it would supply solar cells to French solar module makers to build about 185 megawatt of co-branded solar modules in France under the French national tender program, to be completed over the next two years.
** WIPRO LTD, $13.25, -2.65 pct
India's third-largest software exporter's IT revenue forecast for the quarter ending June was seen as below estimates by some analysts. Wipro on Thursday said it expects IT services revenues to be in the range of $1.72 billion to $1.76 billion.
** MONEYGRAM INTERNATIONAL INC, $12.96, -12.49 pct
JMP Securities downgraded the world's second-largest money transfer company's stock to "market perform" after Wal-Mart Stores Inc said it would launch a domestic money transfer service.
Analysts said more than a third of MoneyGram's earnings were associated with Walmart-to-Walmart transactions. No direct costs could be cut if these transactions go to Wal-Mart's new service.
BofA Merrill Lynch lowered its target price on the stock to $19 from $23.
** TEVA PHARMACEUTICAL INDUSTRIES LTD, $50.91, +0.12 pct
** MYLAN INC, $47.19, +0.58 pct
** MOMENTA PHARMACEUTICALS INC, $11.65, +4.96 pct
The U.S. Supreme Court on Friday denied a request by Teva to stay a lower-court ruling in a patent case that favored the developers of generic versions of the Israel-based company's top-selling multiple sclerosis drug Copaxone.
The decision could help pave the way for generic competitors of Teva's Copaxone drug to go on the market as soon as next month.
The lower-court ruling in July 2013 was in favor of two teams developing cheaper generic forms of Copaxone: one comprising Novartis AG's Sandoz Inc and Momenta Pharmaceuticals, and the other comprising Mylan Inc and Natco Pharma Ltd.
** CBEYOND INC, $9.83, +38.84 pct
Privately held enterprise Internet-based communications services provider Birch Communications Inc said it agreed to buy the data center and networking services provider Cbeyond Inc for about $323 million in cash to expand its optical fiber and data center network.
Cbeyond shareholders will get between $9.97 and $10 per share. At $9.97 per share, the offer represents a premium of 40.8 percent over the closing price of Cbeyond's stock on Thursday.
** ADVANCED MICRO DEVICES INC, $4.135, +12.06 pct
The chipmaker reported better-than-expected quarterly results on Thursday and its second-quarter revenue forecast was above analysts' estimates.
At least two brokerages raised their price targets on the stock on Monday.
** CALPINE CORP, $22.17, +3.74 pct
U.S. power and energy infrastructure owner LS Power Equity Advisors LLC said it has agreed to buy about 3,500 MW of generation resources in the southeastern United States from Calpine for $1.57 billion. The portfolio consists of six combined-cycle generation facilities which use natural gas as the primary fuel source, LS Power Equity said.
Calpine mainly owns and operates natural gas-fired and geothermal power plants in North America.
** PERFECT WORLD CO LTD, $19.68, +0.56 pct
** SHANDA GAMES LTD, $6.71, +1.36 pct
China-based online game developer Perfect World said it joined the consortium offering to buy rival Shanda Games. Perfect World said it would buy 30.3 million class A Shanda Games shares for $100 million from Shanda Interactive Entertainment Ltd, a shareholder in Shanda Games.
** NEWMONT MINING CORP, $25.03, +6.33 pct
The talks between Barrick Gold Corp and Newmont Mining over a combination that would create a gold mining behemoth have hit a snag, but two sources close to the situation say the companies remain keen on a deal and discussions are likely to resume.
** COMCAST CORP, $49.43, +0.67 pct
** CHARTER COMMUNICATIONS INC, $123.5, +4.81 pct
Comcast is in talks with Charter Communications over selling or spinning off roughly 3 million subscribers worth approximately $18 billion to $20 billion as part of the divestitures related to its $45.3 billion takeover of Time Warner Cable, according to a source familiar with the matter.
** VIMPELCOM LTD, $9.23, +2.56 pct
Russia's Vimpelcom has resolved a long-running dispute with the Algerian government by selling it a majority stake in the country's biggest telecoms operator for $2.6 billion, while it will keep control and slash debt.
** WALT DISNEY CO, $78.9, -1.36 pct
Walt Disney Co's cable networks are expected to record high single-digit growth in operating income and domestic affiliate revenue from fiscal 2014 through 2016, Chief Financial Officer Jay Rasulo told investors on Thursday.
** LULULEMON ATHLETICA INC, $49.04, -5.16 pct
A U.S. judge has issued final dismissals of lawsuits accusing Lululemon and various company officials of defrauding shareholders by concealing defects in yoga pants.
** ATHENAHEALTH, $134.3, -7.75 pct
The healthcare IT services company on Thursday reported first-quarter adjusted earnings and revenue that fell below Wall Street estimates.
Three brokerages, including Oppenheimer, Deutsche Bank and B. Riley cut their price targets on the company' stock, citing weakness in its Epocrates business - a mobile medical application.
** SELECT COMFORT CORP, $19.72, +11.10 pct
The specialty mattress maker on Thursday reported first-quarter sales that beat analysts' estimates, helped by a 2 percent rise in comparable sales.
** WEIBO CORP, $22.9999, +13.64 pct
The Chinese Twitter-like messaging service company's U.S.-listed shares were up premarket on Monday after they soared 19 percent on their debut on Thursday.
** ABBOTT LABORATORIES, $38.47, -1.18 pct
An Abbott Laboratories spinoff urged a federal appeals court to revisit a ruling in a case against GlaxoSmithKline Plc , but without disturbing landmark constitutional protections for gays and lesbians.
** CHINDEX INTERNATIONAL INC, $23.62, +2.96 pct
Chinese drugmaker Shanghai Fosun Pharmaceutical Group Co Ltd has raised its offer for U.S.-listed Chindex International Inc by 15 percent to $223.6 million after a bidding war for the China-focused hospital chain.
** RADIOSHACK CORP, $1.48, +4.96 pct
The struggling U.S. electronics chain is mired in talks with its lenders over its plans to close about 1,100 stores, complicating its turnaround efforts, the Wall Street Journal reported, citing sources close to the talks.
RadioShack, which operates about 4,300 stores in the United States, said in March that the plan needed permission from its lenders, adding that its credit agreements allowed it to close only about 200 stores without the approval of lead lenders, the Journal said late on Wednesday. (r.reuters.com/vyg68v)
The company reported a wider quarterly loss and a huge drop in sales during the holiday season. (Compiled by Rohit T.K. in Bangalore; Editing by Joyjeet Das)