The top after-market NASDAQ Stock Market gainers Wednesday are: WCA Waste, Mellanox Technologies, TIBCO Software, Salix Pharmaceuticals, and Ross Stores. The top after-market NASDAQ Stock Market losers are: Alaska Communications Systems Group, VIVUS, SuperMedia, Bed Bath & Beyond, and Sequenom.

Gainers

WCA Waste Corp. (WCAA) stock jumped 29.74 percent to $6.37 in after-market trading. The company said it has entered into an agreement and plan of merger with Macquarie Infrastructure Partners II (MIP II), a North American infrastructure investment fund. MIP II will buy all of the outstanding common stock of WCA for $6.50 per share in cash, redeem all Series A preferred stock and either partially or completely refinance WCA's existing credit facilities. The transaction is valued at about $526 million. The purchase price represents a premium of 30 percent over WCA's closing stock price on Tuesday. WCA said its board has unanimously approved the transaction. The transaction is expected to be completed in the first quarter of 2012.

Mellanox Technologies, Ltd. (MLNX) stock gained 4.22 percent to $32.10 in after-market trading. The shares closed Wednesday's regular trading down 5.41 percent at $30.80.

TIBCO Software Inc. (TIBX) stock increased 4.05 percent to $22.89 in after-market trading. Profit for the fourth quarter was $51.87 million or $0.30 per share, up from $37.49 million or $0.22 per share last year. Adjusted profit was $72.18 million or $0.42 per share, up from $53.84 million or $0.31 per share last year. Revenue rose to $289.51 million from $241.23 million. Analysts had expected profit of $0.35 per share on revenue of $281.28 million. In the conference call, the company said it expects first quarter adjusted earnings of $0.18 to $0.19 per share and revenue of $220 million to $225 million, while Street predicts profit of $0.19 per share on revenue of $215.76 million. The company also reiterated its full year 2012 adjusted earnings per share growth guidance of 15 percent to 20 percent, while Street predicts 16.80 percent growth.

Salix Pharmaceuticals Ltd. (SLXP) stock gained 3.33 percent to $49.31 in after-market trading. The shares closed Wednesday's regular trading up 1.66 percent at $47.72.

Ross Stores Inc. (ROST) stock increased 2.51 percent to $49.01 in after-market trading. The shares closed down 0.10 percent at $47.81 on Wednesday.

Losers

Alaska Communications Systems Group Inc. (ALSK) stock plunged 21.41 percent to $3.45 in after-market trading. The company said its board of directors has approved a fourth quarter dividend of $0.05 per share, payable on Jan. 18, 2012 to shareholders of record as of Dec. 30, 2011. On an annualized basis, this represents a dividend level of $0.20 per share compared to prior level of $0.86 per share, allowing the company to retain $29.8 million cash on an annualized basis. In addition, the company said it anticipates reduced high cost support for wireline and wireless services as a result of Universal Service Fund reform adopted by the Federal Communications Commission and the entry of a fourth competitor in the Alaska wireless market. The company said that increasing its cash position is a prudent policy. This action will provide a continuing dividend for the company's shareholders, while Alaska Communications invests for the future and strengthens its balance sheet.

We see opportunities to strengthen our market position in the enterprise, small to medium business and consumer segments, through accelerated product offerings, continued network investments and enhanced customer service. We also seek to reduce our total debt to strengthen our balance sheet. By proactively managing our balance sheet and making these investments, we intend to create long-term value for our investors, customers, employees and the communities we serve. We look forward to communicating our long-term strategic plan at our year-end earnings call scheduled for March 1, 2012, said Anand Vadapalli, president and CEO of Alaska Communications.

VIVUS Inc. (VVUS) stock fell 9.62 percent to $9.40 in after-market trading. The company reported results from the SEQUEL evaluating the long-term efficacy and safety of Qnexa in 676 overweight and obese subjects with cardiometabolic disease stating that Qnexa therapy was well tolerated. The data suggest that Qnexa, in conjunction with lifestyle modification, may provide a well-tolerated and effective option for the sustained treatment of obesity and the potential to prevent many in this population from progressing to type 2 diabetes. Patients treated with Qnexa had significant, sustained weight loss compared to those in the placebo group over two years. Average weight loss at week 108 was down 9.3 percent and down 10.5 percent, respectively, for the mid- and top-dose as compared to down 1.8 percent for the placebo group. Qnexa patients had improved cardiovascular and metabolic risk factors and a decrease in the need for associated medications in comparison with the placebo group.

SuperMedia LLC (SPMD) stock slid 4.32 percent to $2.8034 in after-market trading. The shares closed Wednesday's regular trading up 6.16 percent at $2.93.

Bed Bath & Beyond Inc. (BBBY) stock declined 3.03 percent to $59.57 in after-market trading. Profit for the third quarter was $228.5 million or $0.95 per share, up from $188.6 million or $0.74 per share last year. Sales grew 6.8 percent to $2.344 billion. Analysts had expected profit of $0.89 per share on revenue of $2.35 billion. Comparable store sales increased by about 4.1 percent. Looking ahead into the fourth quarter, the company expects earnings of $1.28 to $1.33 per share, while Street predicts $1.30 per share. For the full year 2011, the company anticipates earnings of $3.86 to $3.92 per share, while Street predicts $3.83 per share. The company said its full year earnings growth is expected to be 26 percent to 28 percent, up from its previous forecast of 22 percent to 25 percent growth.

Sequenom Inc. (SQNM) stock decreased 2.99 percent to $3.90 in after-market trading. The shares closed Wednesday's regular trading up 2.29 percent at $4.02.