ROSALIND BREWER, CEO AND PRESIDENT OF SAM’S CLUB
Brewer, 51, came in at No. 15. As head of Wal-Mart’s warehouse Sam’s Club, which boasts $56.4 billion in revenue, Brewer runs a major segment of the retail giant’s business. Brewer, who is also a board member for Lockheed Martin, drove Sam’s Club sales up 5 percent, and operating income up 6 percent, and has been building its online business, Fortune noted.