The top after-market NASDAQ stock market losers are: Hansen Natural, Terremark Worldwide, Cubist Pharmaceuticals, National Beverage, Salix Pharmaceuticals, Dynamex, Merge Healthcare, Immucor, Cytokinetics, and P.F. Chang's China Bistro.

Hansen Natural Corp. (HANS) lost 3.41 percent to $49.30 in the after-hours trading.

Terremark Worldwide, Inc. (TMRK) plunged 3.21 percent to $12.35 in the after-market session.

Cubist Pharmaceuticals Inc. (CBST) plummeted 2.64 percent to $21.40 in the after-hours trading. The company said it lowered its fiscal 2010 revenue guidance to range of $634 million to $640 million from previous outlook of $645 million to $650 million, while analysts expect $647.61 million. The company said cost pressures in U.S. hospital continue to impact sales of branded therapies in the hospital setting.

National Beverage Corp. (FIZZ) fell 2.60 percent to $13.11 in the after-market session.

Salix Pharmaceuticals Ltd. (SLXP) dropped 2.26 percent to $43.66 in the after-hours trading. Credit Suisse initiated coverage of Salix with an 'outperform' rating and a price target of $55.

The brokerage said its price target is based on a discounted cash flow analysis, which assumes an 11 percent weighted average cost of capital and a 90 percent probability of FDA approval for Xifaxan in treating non-constipation irritable bowel syndrome or non-C IBS.

We rate SLXP Outperform because it offers a specialty pharma story with scarcity value; high organic revenue growth at the early stages; significant clinical and regulatory derisking of its lead product, Xifaxan; and an underappreciated margin expansion opportunity. We also believe SLXP's attractiveness as a takeout candidate adds option value, said M. Faerm, an analyst at Credit Suisse.

Dynamex Inc. (DDMX) tumbled 2.17 percent to $24.75 in the after-market session. The company said it has terminated the merger agreement previously entered into with affiliates of Greenbriar Equity Group LLC, as a result of the takeover proposal submitted to the company on Dec. 6 by TransForce Inc. (TFI.TO).

TransForce has agreed to acquire the Dynamex for $25.00 per share in cash, which represents a 4.17 percent premium over the consideration provided by the merger agreement previously entered into with affiliates of Greenbriar Equity Group LLC, as amended. The company's board of directors has unanimously approved the merger agreement with TransForce. The transaction is valued at about $248.0 million.

Merge Healthcare Inc. (MRGE) declined 2.04 percent to $3.63 in the after-hours trading.

Immucor Inc. (BLUD) decreased 1.89 percent to $19.76 in the after-market session.

Cytokinetics Inc. (CYTK) moved down 1.86 percent to $2.11 in the after-hours trading.

P.F. Chang's China Bistro, Inc. (PFCB) fell 1.69 percent to $50 in the after-market session.

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