Top Percentage Gainers And Losers As Of 10 a.m. 4/12/2011 (CYH, THC, SKH, JPM, EXEL, GS, TIBX, HPQ, SIFY, WMS, GFRE, EXTR, SB, AIB, CCRT, GIL, THLD, BRNC, SIMG)

Best

1) Community Health Systems (NYSE: CYH): Shares are vaulting 16.57% to $30.18. The stock took a huge hit in yesterday’s session, trading down as low as $22.32 after Tenet Healthcare (NYSE: THC) filed a lawsuit against the company alleging illegal admission of patients in order to benefit financially. The stock is also up despite a downgrade from Above Average to Average at Caris.

2) Skilled Healthcare Group (NYSE: SKH): Stock is enjoying an 11.48% jump. The company recently retained J.P. Morgan (NYSE: JPM) to assist in a possible sale of the company.

3) Excelixis (NASDAQ: EXEL): Trading 7.78% to the upside at $12.34 after a report came out saying that the company is working Goldman Sachs (NYSE: GS) to prepare for takeover offers. The possible sale is in response to a positive study regarding its experimental prostate-cancer drug.

4) TIBCO Software (NASDAQ: TIBX): Shares are enjoying a 6.22% run to $28.70. News surfaced that Hewlett-Packard (NYSE: HPQ) explored a possible purchase of the company two weeks ago.

5) Sify Technologies (NASDAQ: SIFY): Stock is getting a 6.86% pop to $4.83 this morning. The stock has put in a new 52-week high in today’s action.

Other notable movers: Gildan Activewear (NYSE: GIL): Up 5.31% to $33.72; Threshold Pharmaceuticals (NYSE: THLD): Up 4.62% to $2.04.

Worst

1) WMS Industries (NYSE: WMS): Equity is plunging 14.8% to $20.86 after missing Wall Street earnings estimates yesterday.

2) CompuCredit Holdings (NASDAQ: CCRT): Putting in a 12.84% loss to $5.77.

3) Gulf Resources (NASDAQ: GFRE): Losing 11.52% to $4.53. Extreme Networks (NASDAQ: EXTR): Shares are plunging 10.32% to $3.04 after warning of a shortfall in its third quarter revenue. Had been down as much as 20% in pre-market trading.

4) Safe Bulkers (NYSE: SB): Currently trading down 10.15% to $8.32. The company is offering 5 million shares at a 9.3% discount to Monday’s closing price.

5) Allied Irish Banks (NYSE: AIB): Stock is taking a 9.43% hit to $3.17. The company reported that its 2010 net loss rose to 10.23 billion Euros from 2.41 billion Euros in the prior year.

Other notable movers: Bronco Drilling Company (NASDAQ: BRNC): Down 8.95% to $9.56; Silicon Image (NASDAQ: SIMG): Down 7.92% to $6.98.