This summer could not have been going any better for the Celtics.

First, there was a championship 16 years in the making. Then there was a parade that turned downtown Boston into a tsunami of green and white. Then three Celtics brought home Olympic gold medals as members of Team USA’s men’s basketball team.

But right in the middle of this storybook run, there was a plot twist: In July, the team’s ownership group announced that it would be selling the team.

Now, as the Celtics prepare to defend their title, an air of uncertainty hangs over what will happen to the franchise moving forward.

An unexpected sale

On July 1, Boston Basketball Partners LLC announced it was selling all shares of the team.

That group, publicly fronted by Wyc Grousbeck, purchased the team for $360 million back in 2002.

Since then, the value of the team has grown significantly. Forbes valued the Celtics at $4.7 billion last year, the fourth-highest total of any NBA team. Sportico estimates the team is worth around $5.1 billion.

There has been a lot of speculation as to why the Celtics would go up for sale right after snagging a historic 18th championship. Officially, the Grousbecks say they are selling for “estate and family planning considerations.”

But another possible reason, as the New York Post reported, is that the current roster is magnificently expensive.

Franchise faces Jayson Tatum and Jaylen Brown have the NBA’s two biggest contracts ever. And if the Celtics roster remains intact next year, it could cost over $500 million once the luxury tax — a fee imposed on teams that exceed too high above the NBA’s salary cap — is factored in. It would be the single most expensive group of players in the history of the league.

Business as usual

At the Celtics’ media day last month, the team was taking the move in stride.

President of Basketball Operations Brad Stevens said the situation was out of their hands.

“The way that [franchise leadership] phrased it to me since the sale was announced was we just need to keep doing what we’re doing,” Stevens said. “Business as usual and do what you can to build the best team that we can and then we’ll see what happens from there.”

Jaylen Brown described a positive relationship with current ownership.

“Obviously, with that ownership group switching [there] will be some learning and growing that will [need to be] met in order to get accustomed,” Brown said. “Hopefully it’s a smooth transition, that’s what we all hope for. But we’re gonna have to just wait and see.”

Big deal, big price tag

Buying a multi-billion dollar franchise isn’t like going to the local car dealership.

Banks have to be involved, non-disclosure agreements need to signed, and there are a lot of lawyers.

Andrew Zimbalist, an economist with Smith College, said any person or group who acquires the Celtics will have some unique challenges — starting with the arena.

The Celtics don’t own their arena, TD Garden. It’s owned by Delaware North, whose chairman, Jeremy Jacobs, owns the Bruins.

Since the Celtics don’t own the Garden, any new owner won’t be able to make money off of events like concerts that are held there to offset the cost of a championship team, Zimbalist said.

“You have an inferior arena deal, you’ve got a massive payroll, a luxury tax bill that’s coming due next year,” Zimbalist said. “You’re gonna lose a lot, tens of millions of dollars, and you’re gonna still put down $6 billion for a team? It’s a very risky investment to say the least.”

No matter whose buying, it’s a complicated process.

“They have to vet everybody, if they’re not already vetted,” Zimbalist said. “The Celtics are not gonna simply open their books up to any schmo who comes along and says, 'Hey, I want to buy the team.’ You’ve got to have some credibility in the marketplace in order to get to see.”

After going through all of that, any deal would still have to be approved by the NBA’s board of governors. So Zimbalist said he expects that it may be a while before any new owner or ownership group is named.

And whoever is buying will almost certainly clear a new high bar. When Mat Ishbia agreed to buy a majority share of the Phoenix Suns and Mercury in 2022, the deal had a then-record $4 billion value.

Expect there to be a little more green needed for the green and white.