Movers roundup: Cobalt International, Alexion

Among the stock activity stories for Friday, Feb. 10, from AP Business News:

— Shares of oil producer Cobalt International Energy Inc. surged after the company released a study showing that one of its wells might be far more productive than many analysts thought.

— Shares of Alexion Pharmaceuticals Inc. edged higher after the company reported a strong fourth quarter based on improved sales of its blood disorder drug Soliris.