The Boston Celtics’ ownership group has agreed to sell the team to William Chisholm, the managing director and co-founder of Symphony Technology Group, for $6.1 billion, making the sale the largest for a North American sports franchise.

The sale of the NBA’s defending champions by the Grousbeck family, first reported by the Boston Globe and ESPN, is expected to be finalized in late June or July, after review by the NBA Board of Governors.

Chisholm, a Massachusetts native, is a graduate of Dartmouth and the University of Pennsylvania’s Wharton School, and he launched Symphony Technology Group, a private equity firm based in California, in 2002.

“Growing up on the North Shore and attending college in New England, I have been a die-hard Celtics fan my entire life,” Chisholm said in a statement. “I understand how important the Celtics are to the city of Boston — the role the team plays in the community is different than any other city in the country. I also understand that there is a responsibility as a leader of the organization to the people of Boston, and I am up for this challenge.”

The Grousbeck family purchased the Celtics for $360 million in 2002. As part of the sale agreement with Chisholm, Wyc Grousbeck, the franchise’s current governor, will remain in his position through the 2027-28 season.

“We look forward to learning from Wyc and partnering with Brad Stevens, Joe Mazzulla and the talented team and staff to build upon their success as we work to bring more championships home to Boston,” Chisholm said.

Grousbeck’s tenure has produced two championships — in 2008 and 2024 — and 16 postseason appearances in the past 17 seasons. According to Forbes, the Celtics are the fourth-most-valuable NBA franchise behind the Golden State Warriors, New York Knicks and Los Angeles Lakers.

However, Grousbeck told the Boston Globe in June that the franchise was “losing money” during its championship season, and his ownership group announced plans to sell last July. The Celtics’ payroll of $193 million ranks third this season, and the organization has committed to $225 million of contracts for next season. Boston has also given long-term contract extensions to star forwards Jayson Tatum and Jaylen Brown that are worth more than $550 million combined, not including this season.

“We’re fans who bought the team,” Grousbeck told the Globe last summer. “We’re doing this for love. We’re doing this for Celtic pride, and we’re going to put everything we can into the team to win a banner, to win a championship.”

Given the prestige of the Celtics and their large market, the team was certain to bring more than the record $4 billion mortgage industry executive Mat Ishbia paid for the Phoenix Suns in 2023. The agreement also surpasses the $6.05 billion sale price paid for the NFL’s Washington Commanders in 2023. That is expected to end up being $5.85 billion because of a $200 million earnout, or deferred payment, that is contingent on certain revenue markers the team is unlikely to reach, The Washington Post reported in September.

“Bill is a terrific person and a true Celtics fan, born and raised here in the Boston area,” Grousbeck said in a statement. “His love for the team and the city of Boston, along with his chemistry with the rest of the Celtics leadership, make him a natural choice to be the next Governor and controlling owner of the team. I know he appreciates the importance of the Celtics and burns with a passion to win on the court while being totally committed to the community. Quite simply, he wants to be a great owner.”

The Celtics, who are seeking to become the NBA’s first back-to-back champions since the Warriors in 2017 and 2018, enter Thursday’s action in second place in the Eastern Conference with a 50-19 record.