Shares of Hercules (Nasadaq: HERO) added 18% to $4.27, on volumes of 8.1 million shares, or three times its daily average, after Seahawk Drilling Inc. (Nasdaq: HAWK), an offshore-oil driller, on Friday filed for bankruptcy protection and said it would sell its assets to rival Hercules. Seahawk Drilling Inc. shares plunged 36.1% to $5.05.

Citigroup Inc. (NYSE: C) traded in 136.9 million shares early Monday, making it among the volume leaders, gaining momentum toward its daily average of 541.5 million. Share prices dipped 0.3% to $4.86, on word the bank is recruiting about 20 new European banking experts.

First Community Bank Corporation (Nasdaq: FCFL) skidded 58.3% to 50 cents Monday, on volume of 434,781 shares, towering over an all-day volume of 6,355, only days after revealing it was being bought by Community Bank of Manatee.