Tom Ryan

The business of retail pharmacy has undergone dramatic changes in recent years and CVS Caremark Corp., under the leadership of chief executive Tom Ryan, has emerged as one of the industry’s most powerful, well-positioned players. A pharmacist at heart (and by training), Ryan, 54, has a friendly, down-to-earth manner. He also has some of the best instincts in the industry, with a knack for seamlessly integrating acquired companies—from mom-and-pop one-offs to chain competitors—into the CVS portfolio.

Since taking the helm at CVS in 1998, Ryan has expanded the company more than 50%, to more than 6,000 stores coast to coast. What’s more, with the purchase of retail health-clinic operator MinuteClinic and pharmacy-benefit-management and mail-order giant Caremark, he has created a health-care empire, transforming CVS into the nation’s leading integrated pharmacy-services provider.