CEO and President, Reynolds American, 57
After closing the June 2015 Lorillard deal for $27.4 billion—then the largest-ever led by a female CEO—and boosting tobacco giant Reynolds American’s market cap by 19% in the past year, Cameron is a bona fide corporate rock star—again. After retiring from the company in 2011, she returned as CEO three years later for a second tour of duty, devoted to bringing the Newport brand, then owned by Lorillard, into Reynolds American’s orbit. The question: How much longer will Cameron stay? Some analysts think she could step down as soon as November.