Sideline Group Closes $155M Fund I to Invest in the Offline Economy Across Sports, Media, and Consumer Experiences

Everyone spent the last decade chasing digital scale like it was the only game in town, pouring capital into anything that could capture attention through a screen, optimize engagement, and stretch a user session by a few more seconds, while the physical world quietly kept generating real demand, real energy, and real money without needing an algorithm to validate it, and Greg Mazlin leaned into that disconnect before it became obvious.

Sideline Group, a New York City-based investment firm operating where consumer, sports, and media and entertainment collide, just closed its debut fund, Sideline Group Fund I, with $155M in committed capital, not a theory, not a vibe, a deliberate move into what they define as the Offline Economy.

Greg Mazlin brings a track record that does not rely on storytelling to sound good, nearly a decade at Tiger Global, earlier time at Silver Lake, and a personal investing history that maps culture before it becomes consensus, Miami Heat, Athletic Brewing, Angel City Football Club, OLIPOP, Bandit Running, patterns, not punts.

The capital behind the fund is just as telling, a leading U.S. university endowment, family offices, funds of funds, operators, sports team owners, no names needed to understand the signal, this is a room built on allocation discipline, not applause.

Then you follow the capital and the thesis sharpens, Bandit Running is turning individual miles into collective identity, Urban Golf Performance is reworking how people train, blending sport with performance science, MARI, founded by Ari Emanuel, operates global-scale events like the Miami Open and Madrid Open while extending into assets like Frieze and Barrett-Jackson, Milky Way Park is organizing adventure into something structured and scalable. Different categories, same gravity, people showing up in real life.

Emmi Eisner and Daniel Wayland help keep the operation tight, backgrounds across Blackstone and Goldman Sachs, paired with focused strategy execution, lean team, institutional reps.

Zoom out and the macro supports the move, the experience economy is projected to reach $809.8B by 2035, growing at a steady pace, non-digital formats already account for 60.8% of consumer entertainment revenue, the signal is not subtle, people are still outside, still moving, still gathering.

Sideline Group is not chasing a shift, it is aligning with behavior that never left, some capital lives in code, some capital lives where energy, presence, and memory intersect, only one of those still compounds when the screen goes dark.