Greater Nashua

The Boston Celtics are being sold for what would be a record-setting initial valuation of $6.1 billion to a group led by Symphony Technology Group managing partner William Chisholm, the sides said Thursday. The sale — if approved by the NBA’s board of governors after a thorough vetting process — would be the richest in U.S. major pro sports history. That process likely would not be completed until the summer, at the earliest. The $6.1 billion valuation — which would seem to be a minimum, since that is just the initial number — would break the mark set when a group led by Josh Harris bought the NFL’s Washington Commanders for $6.05 billion in 2023. Sportico and ESPN were among those first reporting the agreement for the sale of the reigning NBA champions. Boston Basketball Partners LLC announced last summer that it intended to sell the majority of the Celtics either ...