Benzinga's Top Pre-Market Gainers

Vanguard Health Systems VHS moved up 63.43% to $20.51 in the pre-market session after Tenet Healthcare THC announced its plans to acquire the company for $4.3 billion including debt. Keynote Systems KEYN surged 47.15% to $19.88 in the pre-market session after the company agreed to be acquired by Thoma Bravo for $20.00 per share. Isis Pharmaceuticals ISIS soared 4.77% to $23.04 in the pre-market trading after the company reported Phase 2 data on ISIS-APOCIII Rx. Linn Energy LLC LINE shares gained 3.44% to $34.85 in the pre-market session. Linn Energy has a dividend yield of 9.10%.