Benzinga's Top #PreMarket Gainers

Chubb Corp (NYSE: CB) shares climbed 33.53 percent to $127.00 in pre-market trading after ACE Limited announced its plans to buy Chubb for $28.3 billion.

AlarmCom Hldg Inc (NASDAQ: ALRM) gained 10.92 percent to $17.06 in pre-market trading after falling 2.47 percent on Tuesday.

ACE Limited (NYSE: ACE) shares rose 9.68 percent to $111.52 in pre-market trading after the company agreed to buy Chubb for $28.3 billion.

Travelers Companies Inc (NYSE: TRV) shares rose 4.70 percent to $101.20 in pre-market trading after gaining 0.43 percent on Tuesday.

Alder Biopharmaceuticals Inc (NASDAQ: ALDR) shares climbed 3.93 percent to $55.05 in pre-market trading after the company reported that the underwriters of its earlier announced public offering of common stock have exercised in full their option to purchase an additional shares.