A group led by William Chisholm and backed by private equity fund Sixth Street has reached an agreement to buy the Boston Celtics, according to multiple people familiar with the agreement, in what will be the most expensive NBA team sale in history.
The managing partner of Symphony Technology Group, Chisholm has agreed to buy the team in two stages, which was the stated goal of the Celtics’ current ownership, led by the Grousbeck family. The deal values the team at $6.1 billion in the first payment.
Irving and Wyc Grousbeck announced the deal Thursday morning in a letter to Celtics investors. Sixth Street has committed more than $1 billion to the deal, according to multiple people familiar with the process. The group also includes Rob Hale, a current Celtics investor, and Bruce A. Beal Jr., president of Related Companies.
Wyc Grousbeck will remain the team’s governor through the 2027-28 season.
The agreement concludes a sale that was closely tracked, both in the NBA and other U.S. leagues, as a barometer for sports valuations overall. The Celtics are among the NBA’s most successful and most popular franchises, but they are a tenant in their arena and own just a small piece of their local media partner. Sportico values the team at $5.66 billion. A common question among insiders over the past few months has been whether the team would sell for more or less than $6 billion.
This deal carries a blended valuation of about $6.6 billion. That’s by far the most ever paid for control of an NBA team, eclipsing the $4 billion valuation when Mat Ishbia bought the Phoenix Suns a few years ago.
Chisholm was born and raised in Massachusetts and attended Dartmouth College, as did two of his children. He is the co-founder, managing partner and chief investment officer of STG, which is based in Menlo Park, Calif. STG’s portfolio includes more than 50 active and closed investments, with about $10 billion of assets under management, as of March 2023. Prior to starting STG, Chisholm co-founded The Valent Group, and he also worked at Bain & Company and PaineWebber.
Sixth Street has more than $100 billion in assets under management. In addition to its Giants LP, its other sports holdings include Legends and NWSL club Bay FC, plus minority investments in the San Antonio Spurs, Real Madrid and FC Barcelona.
Sixth Street would join Arctos Partners and Blue Owl as PE firms with multiple NBA team investments. Arctos is invested in the Golden State Warriors, Philadelphia 76ers, Sacramento Kings and Utah Jazz, while Blue Owl holds stakes in the Atlanta Hawks, Minnesota Timberwolves and Kings.
The current Celtics owners bought the NBA team in 2002 for $360 million. They announced that the franchise was for sale last July, less than two weeks after winning an NBA-record 18th championship. The group’s stated reason was estate planning in the Grousbeck family, who currently control the team. Irving Grousbeck is about 90 years old, and his son Wyc has run the team for years. Wyc said that week that his family wanted to sell the Celtics in two stages—51% now, and the rest in 2028—with the provision that he stays in control until the second transaction closes.
Sportico reported last week that four groups remained engaged in the process. They were Chisholm, Phillies owner Stan Middleman, the Friedkin Group, and existing investor Steve Pagliuca. Pagliuca was viewed by many throughout the process as a front-runner.
BDT & MSD and JPMorgan Chase co-led the sale process for the Celtics. Jordan Park served as an advisor the Grousbecks.