EVP and COO, Walmart U.S., Walmart, 50
McKenna is helping turn the tide at Walmart’s biggest division, where she has headed operations since December 2014. The U.S. business, with $298.4 billion in sales, has now had two years of positive same-store sales—an important industry metric. McKenna has been key in the company’s decision to invest $2.7 billion in training programs and raises for some 1.2 million U.S. store employees. She’s also pushing tech: Now all store and department managers get mobile devices so that they can spend more time on the floor rather than in the back room.