Barnes & Noble (BKS) shares surged 62 percent Monday on news that Microsoft is investing $300 million in a new venture that will include the bookstore chain's digital and college businesses. Barnes & Noble shares were up $8.52 at $22.20 in heavy midday trading. Microsoft shares (MSFT) were unchanged at $31.98.
Among other big gainers Monday was Sunoco (SUN), up nearly 20 percent at $48.88 after Energy Transfer Partners announced a plan to buy the oil refiner for $5.3 billion. Energy Transfer Partners (ETP) was up about 3 percent.
In other deal-related trading, Gen-Probe Inc. (GPRO) was up 19 percent at $81.61, while Hologic (HOLX) was down about 10 percent at $19.16. Hologic, a maker of medical devices, announced plans to buy Gen-Probe, a diagnostic test maker, for about $3.72 billion in cash.
Exceed Company (EDS), a Chinese apparel maker, was up 65 percent at $3.45 a share after posting 2011 earnings. Cleantech Solutions International (CLNT), another Chinese company, was up about 25 percent at $5.66.
Demand Media (DMD), an online content creation company that went public earlier this year, was up 23 percent at $8.91.
Among Monday's losers was Verifone Systems (PAY), down about 10 percent. The maker of credit card swipe systems was downgraded by Deutsche Bank, which questions the company's growth projections, according to Reuters.
Tenneco (TEN) also was down about 10 percent after the auto parts maker posted a decline in earnings.
The Dow Jones industrial average was down 40 points at midday, and broader indexes also were lower.