FORTUNE's annual ranking of America's leading businesswomen

21 of 50
21. Gisel Ruiz
Gisel Ruiz
EVP and COO, Wal-Mart U.S.
Wal-Mart Stores
2011 rank: New
Age: 42
Ruiz, who started at Wal-Mart in 1992 as a store management trainee, made the jump from human resources to operations when she took over as COO of the U.S. business in February. Her reach is massive: The U.S. division has 1.4 million associates, more than 3,800 stores, and $264 billion in sales.
From the October 8, 2012 issue
How we pick the Power 50
The list is compiled by FORTUNE editors, who consider four criteria: the size and importance of the woman's business in the global economy, the health and direction of the business, the arc of the woman's career (resume and runway ahead), and societal and cultural influence.