Private equity mogul William Chisholm has reached an agreement to purchase the Boston Celtics for at least $6.1 billion, making it the most expensive sale in U.S. professional sports history. 

If approved by the NBA's Board of Governors this summer, the deal would surpass the $6.05 billion spent on the NFL's Washington Commanders in 2023.

Chisholm, a Massachusetts native and managing partner of Symphony Technology Group, leads the new ownership group alongside Boston businessmen Rob Hale and Bruce Beal Jr. A lifelong Celtics fan, Chisholm expressed his deep connection to the team and his commitment to Boston’s basketball legacy.

The current ownership group, led by Wyc Grousbeck, purchased the team in 2002 for $360 million. Grousbeck will remain as CEO and Governor for the next three seasons at Chisholm's request.

The agreement involves a two-stage sale- Chisholm will first acquire 51% of the team, with the remaining shares available for purchase by 2028 at an increased valuation, potentially pushing the team's worth to $7.3 billion. Chisholm outbid multiple contenders, including Celtics minority partner Steve Pagliuca.

The Celtics, who won their record 18th NBA title last June, remain strong contenders this season, led by young stars Jayson Tatum and Jaylen Brown