24 Hour Fitness Sold to Founder Mark Mastrov, PE Firm

Mastrov, one of the fitness industry’s most iconic figures, is returning to the gym brand he founded as owner and executive chair, partnering with LongRange Capital to drive growth

One of the first fitness industry deals of 2026 sees 24 Hour Fitness reuniting with its founder.

The gym chain said Wednesday that founder Mark Mastrov—who scaled the business from a single club to 420 locations and 4.5 million members before selling it in 2005 in a deal valued at more than $1.6 billion—is returning as owner and executive chair after partnering with LongRange Capital to acquire 24 Hour Fitness.

“Mark founded and built 24 Hour Fitness into the powerhouse brand it is today, and the organization is inspired and energized by his return,” 24 Hour Fitness president and CEO Karl Sanft said. “With the business stronger than ever and our investments aligned with what members value most, this is the perfect time to welcome him back. Together with LongRange Capital, we’re ready to accelerate our growth story.”

The deal was first reported by Axios, which noted that 24 Hour Fitness is currently down to around 240 locations following pandemic-era struggles.

With the deal now in place, 24 Hour Fitness said it plans to announce new initiatives, partnerships and global expansion plans throughout the year.

“LongRange Capital was founded on the belief that through strategic support, patient capital and a focus on delivering greater value for customers, companies can develop into exceptional businesses over the medium- and ultimately long-term,” LongRange Capital founder and managing partner Bob Berlin said. “24 Hour Fitness has an iconic legacy and significant opportunity ahead, and we’re excited to partner with Mark, Karl and the exceptional team at 24 Hour Fitness during this next phase of growth.”

The deal follows a new campaign from 24 Hour Fitness highlighting remodeled locations equipped with upgraded equipment, general managers certified in personal training, dozens of clubs featuring Recovery24, a dedicated recovery zone and select locations offering Reformer24 studios for Pilates fans.

Beyond 24 Hour Fitness, Mastrov invested in and advised a range of fitness brands, including Crunch Fitness and UFC Gym.