Benzinga's Top #PreMarket Gainers

shares rose 24.03% to $52.50 in pre-market trading after Spain's Iberdrola SA announced its plans to buy UIL Holdings for about $3 billion.

shares surged 15.12% to $69.50 in pre-market trading. Cyberonics and Sorin Group announced a $2.7 billion merger agreement. Cyberonics also reported better-than-expected Q3 earnings.

gained 12.95% to $71.01 in pre-market trading after the company reported in-line earnings for the fourth quarter.

shares climbed 7.41% to $7.25 in pre-market trading. Town Sports International reported a Q4 loss of $2.62 per share on revenue of $109.7 million. Town Sports announced the engagement of financial advisor to consider strategic alternatives. The company named Daniel Gallagher as CEO and Robert Giardina as Chairman of the Board.

shares gained 5.10% to $37.09 in the pre-market trading session after the company reported stronger-than-expected results for the fourth quarter.