Afternoon Market Movers

Market Gainers

STEC STEC skyrocketed 87.05 percent to $6.71 after news that Western Digital WDC will buy the company for around $340 million.

Vanguard Health Systems VHS soared 66.81 percent to $20.93 after Tenet Healthcare THC announced its plans to acquire the company for $4.3 billion including debt.

Keynote Systems KEYN shot up 46.71 percent to $6.31. The volume of Keynote Systems shares traded was 5255% higher than normal. Keynote agreed to be acquired by Thoma Bravo for $20.00 per share.

Isis Pharmaceuticals ISIS traded up 20.23 percent to $26.41 after the company reported Phase 2 data on ISIS-APOCIII Rx that will reduce blood fat.

Market Losers

Solazyme SZYM tumbled 16.88 percent to $10.49 after the company agreed with Roquette Frères to dissolve their joint venture, Solazyme Roquette Nutritionals LLC.

YY YY fell 12.87 percent to $24.01 after shares traded 353 percent higher than normal last week. Analysts are still bullish on the company.

Golden Minerals AUMN plunged 15.46 percent to $1.34 after the company announced suspension of production at its Velardena mine as of June 21, 2013. The decision mainly aim to conserve the company asset until operating plans and prices for silver and gold indicate a sustainable cash margin for operations.