The record $6.1 billion Boston Celtics sale will be finalized within the next week or so and the deal structure will be compliant with NBA private-equity ownership rules, Front Office Sports has learned. Lead buyer Bill Chisholm’s group now has enough money to cover the cost of the deal and is in fact “oversubscribed,” two sources tell FOS. The group will acquire more than 51% of the franchise in the first tranche of the deal, one source says. The exact size stake Chisholm will end up owning is still unclear.