Based on the NBA’s latest cap projection, the five-year contract will start at approximately $54.13M and will be worth a total of $313.93M, making it the largest deal in league history. It will replace the $37M player option for 2025-26 from Tatum’s current contract and will run through the ’29-30 season.

Tatum, who won his first championship this spring, earned All-NBA First Team honors for a third straight season after averaging 26.9 points, 8.1 rebounds and 4.9 assists in 35.7 minutes per game with a .471/.376/.833 shooting line for the league’s top team.

The star forward met the supermax criteria, increasing his maximum salary from 30% of the cap to 35%, by making the All-NBA team in both 2022 and 2023. He needed one more year in the NBA in order to meet the service time criteria of at least seven years, but this move had been expected since last spring once he became eligible.

Tatum’s deal, which can be officially signed as early as July 6, is on track to be completed less than one year after his teammate Jaylen Brown signed a five-year supermax extension of his own. Brown’s deal, which went into effect today and previously held the title of biggest contract in NBA history, is worth approximately $285.4M.

Having also agreed to a four-year, $125.9M extension with guard Derrick White earlier Monday, the Celtics have locked up three of their five starters through at least the 2027-28 season, with a fourth (Jrue Holiday) holding a player option for that year. 

Boston’s fifth starter (Kristaps Porzingis) is under contract through ’25-26. It projects to be one of the league’s priciest rosters going forward, but the Celtics now have their championship core under team control for the long term.

The Celtics will become one of four teams who have multiple players on maximum-salary contracts that began at 35% of the cap. The Bucks (Giannis Antetokounmpo, Damian Lillard) and Sixers (Joel Embiid, Paul George) will have two apiece, while the Suns (Kevin Durant, Devin Booker, Bradley Beal) are carrying three.