
The Avengers Tower finally returned in Thunderbolts* and left some wondering if Valentina Allegra de Fontaine (Julia Louis-Dreyfus) was the true buyer all along. The New York skyscraper debuted in 2012's The Avengers as Stark Tower before being converted into Earth's Mightiest Heroes' new headquarters. Spider-Man: Homecoming kickstarted the buyer mystery in 2017 as it revealed that Robert Downey Jr.'s Tony Stark sold Avengers Tower to a new owner.
CIA director Valentina leads the villainous charge in Thunderbolts* opposite a ragtag team of anti-heroes including Yelena Belova (Florence Pugh), Bucky Barnes (Sebastian Stan), U.S. Agent (Wyatt Russell), Red Guardian (David Harbour), and Ghost (Hannah John-Kamen).
Who Really Bought Avengers Tower in the MCU?

Fans have speculated that everyone from the Fantastic Four to Oscorp bought Avengers Tower, while the true answer has been a closely guarded secret.
That said, Marvel Studios has clearly had the answer locked away this whole time, as M.J. actress Zendaya narrowly stopped Spider-Man star Tom Holland from spoiling the truth as far back as December 2021.
Thunderbolts* finally reveals that CIA director Valentina Allegra de Fontaine has bought Avengers Tower and rebranded it as The Watchtower. She seemingly uses the former superhero HQ as the base of operations for her O.X.E. Group, an entity through which she runs her shady black ops missions and projects.
Director Jake Schreier addressed the Avengers Tower takeover in an interview with Empire, explaining how its nefarious new owner, Valentina, could be a "symbol of things taking a darker turn" in the MCU:
“We know what that tower means. Who’s the person you would least like to own that tower, that means so much to so many people? Can you use that as a symbol of things taking a darker turn?”
In the aftermath of Thunderbolts*, the team, still begrudgingly working under Valentina, is now known as the New Avengers. The movie's second post-credit scene confirmed that the MCU's newest superhero team is still operating out of The Watchtower, with some speculating it may be renamed, New Avengers Tower.
Why the New Avengers Tower Will Be All-Important in the MCU

The New Avengers taking over the former Avengers Tower and Watchtower helps give them credibility as the successor to Earth's original Mightiest Heroes. Going forward, the iconic MCU skyscraper ought to be seen in most projects in which the team appears, presumably including next year's Avengers: Doomsday.
Going forward, it's unclear what the future holds for the New Avengers beyond their role as one of several superhero teams in Doomsday and Secret Wars.
Perhaps they could one day get their own ensemble flick in the MCU's next saga under their New Avengers moniker, especially as any movie with "Avengers" in the title is bound to help drive its box office.
If that does happen, fans should expect most of the team to return, provided they all survive Avengers 5 and 6, along with Sentry, likely more accustomed to his powers after using them in the imminent Multiversal conflict.
Marvel Comics readers may be familiar with The Watchtower as the Sentry's headquarters, which is similarly located in Manhattan, New York. After Sentry was defeated by his archnemesis, the General, he used his powers to make the whole planet forget he existed and make the Watchtower disappear in everyone's eyes.
As part of this storyline, Tony Stark built his own new office tower in the space occupied by The Watchtower and used it as a base for the New Avengers, to which Sentry was eventually recruited. The Watchtower, still hidden, was eventually placed above the new Stark Tower, but was still ignored by everyone.
While the story has played out drastically differently in the MCU, the ties between Stark Tower, The Watchtower, Sentry, and the New Avengers have lingered around, clearly taking elements from Marvel Comics.