Elon Musk on Monday unveiled a new black and white "X" logo as a replacement for the social media platform's familiar blue bird symbol, marking a major rebranding of the company he bought for $44 billion last year.

Musk replaced his own Twitter icon with a white X on a black background and posted a picture on Monday of the design projected on Twitter’s San Francisco headquarters.

The X started appearing on the top of the desktop version of Twitter on Monday, but the bird was still dominant across the phone app. Some users saw a blue version of the X logo, suggesting the rollout was not yet finalized.

Musk and Twitter Chief Executive Officer Linda Yaccarino announced the rebranding Sunday, saying the company would be renamed X and move later into payments, banking, and commerce.

"X is here! Let's do this," said Yaccarino, who also posted a picture of the logo projected on the company's offices in San Francisco.

"#GoodbyeTwitter" was trending on the platform with reference to the old logo as several users criticized the new one.

Musk had asked fans for logo ideas and chose one, which he described as minimalist Art Deco, saying it "certainly will be refined."

"And soon we shall bid adieu to the twitter brand and, gradually, all the birds," Musk tweeted Sunday.

The billionaire is the CEO of the rocket company Space Exploration Technologies Corp., commonly known as SpaceX. In 1999, he founded a startup called X.com, an online financial services company now known as PayPal.

Musk changed his profile picture late Sunday to the company's new logo and updated his Twitter bio to "X.com," which now redirects to twitter.com.

In response to questions about what tweets would be called when the rebranding is done, Musk said they would be called Xs.

Founded in 2006, Twitter takes its name from the sound of birds chattering, and it has used avian branding since its early days, when the company bought a stock symbol of a light blue bird for $15, according to the design website Creative Bloq.

The original logo was designed in 2012 by a team of three. "The logo was designed to be simple, balanced, and legible at very small sizes, almost like a lowercase 'e,'" tweeted Martin Grasser, one of the designers.

"Powered by AI, X will connect us in ways we're just beginning to imagine," Yaccarino tweeted on Sunday.

Yaccarino, a former advertising sales executive at NBCUniversal who Musk hired last month to be Twitter's CEO, said the social media platform was on the cusp of broadening its scope.

"X is the future state of unlimited interactivity – centered in audio, video, messaging, payments/banking – creating a global marketplace for ideas, goods, services and opportunities," Yaccarino tweeted.

New revenue streams

Since Musk bought Twitter last October, the platform's advertising business has partially collapsed as marketers soured on the billionaire's management style and mass firings at the company that gutted content moderation.

In response, the SpaceX boss has moved toward introducing payments and commerce through the platform in a search for new revenue.

Weeks before completing his acquisition, Musk had said that buying the company would speed up his ambition to create an "everything app" called "X" by three to five years. Such an app could still function as a social media platform and also include messaging and mobile payments.

Musk had previously said he wanted to create a super-app modeled on China's WeChat, a social media platform that also offers messaging and mobile payments.

"You basically live on WeChat in China because it's so usable and helpful to daily life, and I think if we can achieve that, or even get close to that at Twitter, it would be an immense success," he told a company town hall meeting in June last year.

Simon Kemp, CEO of digital consultancy Kepios, said he was skeptical that Twitter could evolve into a super-app.

"Given how Musk has treated Twitter's own employees since the acquisition, I don't imagine many developers will rush to build third-party apps to integrate into the Twitter ecosystem unless Musk can offer outstanding incentives, and that'll be extra tricky given the company's existing debt."

But he also said the platform had the potential to become "a great (global and paid) news aggregator."

Twitter is thought to have around 200 million daily active users, but it has suffered repeated technical failures since Musk sacked much of its staff.

Many users and advertisers alike have responded adversely to the social media site's new charges for previously free services, its changes to content moderation and the return of previously banned right-wing accounts.

Musk said this month that Twitter had lost roughly half of its advertising revenue since he took control.

Facebook parent Meta also this month launched its text-based platform, called Threads, which has up to 150 million users, according to some estimates.

But the amount of time users spend on the rival app has plummeted in the weeks since its launch, according to data from market analysis firm Sensor Tower.