24 Hour Fitness is the worl's largest (by memberships) privately owned and operated fitness center chain, and 3rd in number of clubs behind Gold's Gym and Fitness First of Australia. The company's corporate office is located in Carlsbad, California. The operations' headquarters is in San Ramon, California in the Bay area. 24 Hour Fitness has over 19,000 employees. The founder is Mark S. Mastrov and current CEO is Carl Liebert III. 24 Hour Fitness is currently a subsidiary of the private equity firm Forstmann Little & Company, since its acquisition in a $1.6 billion leveraged buyout in 2005.