The owners of the Boston Celtics have retained JPMorgan Chase and BDT & MSD to facilitate the sale of the NBA franchise, according to someone with direct knowledge of the process.

The two firms will work together in the sale, said the person, who was granted anonymity because the details are private. It’s a prestige contract: the Celtics, one of the most recognizable brands in U.S. sports, are expected to fetch more than anyone has ever paid for control of an NBA team.

The Celtics owners announced the sale last month, less than two weeks after the franchise won its NBA-record 18th championship. Wyc Grousbeck, the team’s governor, later said he wants the sale to happen in two phases—51% now and the rest in 2028, with the provision that he stays in control until the second transaction closes.

Sportico values the Celtics at $5.12 billion, fourth-most in the NBA and 21st among all U.S. franchises. The highest valuation ever set in an NBA control sale was $4 billion, from Mat Ishbia‘s 2022 purchase of the Phoenix Suns.

Grousbeck’s group bought the Celtics in 2002 for $360 million. The consortium, which includes Bain Capital senior advisor Steve Pagliuca and Abbey Group founding partner Bob Epstein, is named Banner 17 for their desire to win the Celtics’ 17th title, which was accomplished in 2008.

The group is selling because of family estate planning, a common reason for major (and minor) sports transactions. Family patriarch Irv Grousbeck is around 90 years old, and his estate planning over the past few years has centered around what happens to the family’s most valuable asset when it ultimately passes to his four children. The Celtics have appreciated about 14x over the course of their ownership, which is a lot of money tied up in an illiquid asset. The family has ultimately decided to turn that into cash.

JPMorgan Chase has a long history of providing stadium financing and advising clients on sports team transactions. BDT & MSD is the result of the 2023 combination of Byron Trott’s BDT & Co. and Michael Dell’s MSD Partners. The Jordan Park Trust Company, as the Grousbeck family advisor, oversaw the advisor selection process and will continue to be actively involved in the sale process.

The multi-phase preference may prove difficult. It would involve someone paying billions for an asset without gaining immediate control, and it would also require NBA approval. The last NBA team to sell in set phases, the Minnesota Timberwolves, is currently locked in a legal battle over the contract, and commissioner Adam Silver told Sportico in April that the league may have to “reassess what sort of transactions we allow.”

(This story has been updated with information that the Jordan Park Trust Company oversaw the advisor selection process.)