24 Hour Fitness

24 Hour Fitness is a privately held and operated fitness center chain headquartered in Carlsbad, California. It is the second largest fitness chain in the United States based on revenue after LA Fitness, and the fourth in number of clubs (behind LA Fitness, Anytime Fitness & Gold's Gym), operating 287 clubs across 11 U.S. states. The company was originally founded by Mark S. Mastrov and was sold to Forstmann Little & Co in 2005, and then to AEA investors and Ontario Teachers Pension Plan in 2014.

After COVID-19 forced gym closures and ravaged the fitness industry in 2020, the company filed for bankruptcy in June 2020, closed over 100 clubs, and successfully emerged from bankruptcy under new owners Sculptor Capital Investments LLC, Monarch Alternative Capital LP and Cyrus Capital Partners LP in December, 2020.