Atlanta, GA, July 08, 2025 — Harbinger Sports Partners Fund I, LP, the $750 million private equity fund focused on minority investments in major U.S. professional sports franchises, led by industry heavy weights Mark Cuban, Steve Cannon and Rashaun Williams, proudly announces the appointment of Jonathan Mariner as General Partner.
A transformative figure in the business of sports, Mariner brings more than two decades of leadership at the highest levels of professional leagues, teams, and corporate boards. As former Chief Financial Officer and Chief Investment Officer of Major League Baseball, Mariner helped guide the league to sustained profitability, oversaw its $2 billion league-wide credit facility, and managed the creation and growth of MLB’s strategic investment fund to over $1.2 billion in assets. His career also spans roles as CFO of the Florida Marlins, Florida Panthers, and Dolphins Stadium, as well as significant board service across multiple Fortune 500 companies and innovative sports ventures.
“Jonathan’s unparalleled experience across league offices, franchises, media assets, and strategic investments makes him a generational addition to Harbinger,” said Rashaun Williams, Founder and Managing Partner. “He represents exactly what sets us apart: operational fluency, financial discipline, and a commitment to responsible ownership.”
“Joining Harbinger is an opportunity to help shape the next chapter of institutional investment in U.S. sports,” said Jonathan Mariner. “I look forward to combining my league-level perspective with the team’s operational and strategic expertise to unlock value for franchise partners and investors alike.”
Mariner joins an accomplished leadership team, including:
Rashaun Williams, Founder and Managing Partner, venture investor and Limited Partner of the Atlanta Falcons.
Steve Cannon, Co-Founder and Managing Partner, former CEO and Vice Chairman of AMB Sports and Entertainment (Atlanta Falcons, Atlanta United FC) and former CEO of Mercedes-Benz North America.
Mark Cuban, General Partner, longtime NBA owner of the Dallas Mavericks and investor.
Harbinger’s strategy remains focused on acquiring 1–5% minority stakes in a curated universe of 92 U.S.-based professional franchises, bringing data-driven rigor and operational insight to a historically illiquid asset class.
“Jonathan’s breadth of experience across finance, governance, and team operations will help us add tangible value to franchise partners,” said Steve Cannon, Co-Founder and Managing Partner. “We’re thrilled to welcome him to the team.”