WebMD Health, an Internet Brands company and a provider of health information services for consumers, physicians and other healthcare professionals, completed the acquisition of Mercury Healthcare, a technology and data analytics company, from Vestar Capital Partners, a private equity firm. Financial terms were not disclosed. "Vestar is proud to have supported the transformation of Healthgrades and Mercury over the last decade as they have become true leaders in consumer and b2b healthcare engagement," Norm Alpert, Vestar Founding Partner.