The Celtics will soon be under new ownership.

A group led by William Chisholm has agreed to purchase Boston’s iconic NBA franchise from the Grousbeck family for $6.1 billion, a source told the Herald on Thursday.

The team expects to finalize the sale, which is pending a review by the NBA Board of Governors, in late June or early July. If confirmed, it will be the highest price ever paid for an American professional sports franchise, shattering the previous NBA record of $4 billion held by Mat Ishbia’s Phoenix Suns.

Wyc Grousbeck, the face of the Celtics’ ownership group since Boston Basketball Partners LLC purchased the team for $360 million in 2002, plans to remain in his roles as team CEO and governor through the 2027-28 season.

Chisholm, a lifelong Celtics fan who was raised on the North Shore and attended Dartmouth College, is the co-founder, managing partner and chief investment officer at Symphony Technology Group, a private equity firm based in California. He will work alongside Grousbeck before taking control of the franchise’s operations in 2028.

The Celtics have been one of the NBA’s most successful franchises during the Grousbecks’ ownership tenure, reaching four NBA Finals, winning two championships and ranking second in the league in total wins behind the San Antonio Spurs.

Weeks after the Celtics won their most recent NBA title, in a five-game series victory over the Dallas Mavericks last June, the Grousbeck family announced it was selling its majority stake in the franchise for “estate and family planning considerations.”

It’s unclear what impact, if any, the transition to Chisholm will have on Boston’s payroll plans for next season, when the Celtics’ roster is projected to cost close to $500 million between salaries and luxury tax penalties. All five Celtics starters — including the owners of the two most lucrative contracts in NBA history, All-Stars Jayson Tatum and Jaylen Brown — and core reserves Payton Pritchard and Sam Hauser are under contract through at least the 2025-26 campaign.

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