Benzinga's Top #PreMarket Gainers

bluebird bio

shares gained 91.64% to $50.00 in pre-market trading following the presentation of positive data on LentiGlobin BB305 at the European Hematology Association (EHA). Covidien plc

jumped 34.68% to $97.00 in pre-market trading after Medtronic

announced its plans to buy Covidien for $42.9 billion in cash and stock. Fusion-io

shares jumped 22.84% to $11.40 in pre-market trading after SanDisk

announced its plans to buy Fusion-io for $11.25 per share in cash. Sequenom

shares jumped 22.22% to $3.74 after the company reported the US FDA premarket clearance to market two tests. Williams Companies

soared 12.23% to $52.95 in the pre-market trading following the announcement of acquisition of Global Infrastructure Partners' GP and LP interests in Access Midstream Partners for $5.995 billion. TW Telecom

climbed 11.45% to $40.50 after the company agreed to be acquired by Level 3 Communications

in a stock-and-cash transaction valued at $40.86 per share.