Vivus Inc. (Nasdaq: VVUS) shares rose 11.7% to $7.05 early Monday morning, on volume of 6.4 million shares, or double its all-day average. This, after the company said its experimental weight-loss drug yielded positive results and helped cut blood pressure.

Citigroup Inc. (NYSE: C) was an early volume leader Monday, dealing in 79 million, compared to a daily average of 494.6 million. Share prices slid 0.5% to $4.43,

Ambassadors International Inc. (Nasdaq: AMIE) shares tumbled 69.6% to 85 cents, on volume of 2.5 million shares, towering over a daily average around 101,000, after the parent of Windstar Cruises filed for bankruptcy protection on Friday.