Elon Musk is no longer Twitter's largest shareholder and says he's 'not sure' his takeover bid will be successful

• Elon Musk, who has a 9.2% stake in Twitter, is no longer its largest shareholder.
• Vanguard Group said its funds now own a 10.3% stake, according to a recent SEC filing.

Elon Musk has lost his position as Twitter's largest shareholder as he attempts to buy the company in a $43 billion deal.

The Tesla and SpaceX boss said in early April he had become Twitter's largest shareholder, having built a 9.2% stake in the micro-blogging platform.

But he has now lost the top spot: An asset manager at Vanguard Group said in a filing submitted recently to the Securities and Exchange Commission that, as of April 8, its funds now own a 10.3% stake in the company, which is worth $3.6 billion as of Friday's close.

The filing shows Vanguard increased its stake in Twitter over the course of the first quarter.

On Thursday, the world's richest man unveiled a $43 billion bid for the entire company, in a take-it-or-leave-it offer.

Musk is still the largest individual shareholder, with Twitter cofounder Jack Dorsey the second largest. Musk said on Thursday, hours after making the offer, that he's "not sure" whether his takeover bid will be successful.

"I am not sure that I will actually be able to acquire it," Musk said while speaking at the TED 2022 conference in Vancouver on Thursday.

Musk said that he had a "plan B" if his bid was unsuccessful, but did not elaborate on what that would be.

Speaking to TED chief, Chris Anderson, Musk explained that he made the offer because he believes it's important to have an "inclusive arena for free speech."

"This is not a way to make money," Musk said. "My strong intuitive sense is that having a public platform that is maximally trusted and broadly inclusive is extremely important to the future of civilization."

In a letter to Twitter's chairman on Wednesday, Musk said his $54.20-per-share offer was his "best and final" offer.

He said if the offer isn't accepted, he may dump his massive stake in the company and walk away entirely.

Twitter confirmed Thursday that it had received "an unsolicited, non-binding proposal from Elon Musk" and said it would "carefully review the proposal to determine the course of action that it believes is in the best interest of the company and all Twitter stockholders."

Musk tweeted on Thursday that it would be "utterly indefensible" for Twitter to not put his offer to a shareholder vote.