Yaccarino posted a positive message Wednesday about her tenure at the company formerly known as Twitter and said “the best is yet to come as X enters a new chapter with” Musk’s artificial intelligence company xAI, maker of the chatbot Grok. She did not say why she is leaving.

Musk responded to Yaccarino’s announcement with his own 5-word statement on X: “Thank you for your contributions.”

“The only thing that’s surprising about Linda Yaccarino’s resignation is that it didn’t come sooner,” said Forrester research director Mike Proulx. “It was clear from the start that she was being set up to fail by a limited scope as the company’s chief executive.”

In reality, Proulx added, Musk “is and always has been at the helm of X. And that made Linda X’s CEO in title only, which is a very tough position to be in, especially for someone of Linda’s talents.”

Musk hired Yaccarino, a veteran ad executive, in May 2023 after buying Twitter for $44 billion in late 2022 and cutting most of its staff. He said at the time that Yaccarino’s role would be focused mainly on running the company’s business operations, leaving him to focus on product design and new technology. Before announcing her hiring, Musk said whoever took over as the company’s CEO “ must like pain a lot.”

In accepting the job, Yaccarino was taking on the challenge of getting big brands back to advertising on the social media platform after months of upheaval following Musk’s takeover. She also had to work in a supporting role to Musk’s outsized persona on and off of X as he loosened content moderation rules in the name of free speech and restored accounts previously banned by the social media platform.

“Being the CEO of X was always going to be a tough job, and Yaccarino lasted in the role longer than many expected. Faced with a mercurial owner who never fully stepped away from the helm and continued to use the platform as his personal megaphone, Yaccarino had to try to run the business while also regularly putting out fires,” said Emarketer analyst Jasmine Enberg.

Yaccarino’s future at X became unclear earlier this year after Musk merged the social media platform with his artificial intelligence company, xAI. And the advertising issues have not subsided. Since Musk’s takeover, a number of companies had pulled back on ad spending — the platform’s chief source of revenue — over concerns that Musk’s thinning of content restrictions was enabling hateful and toxic speech to flourish.

Most recently, an update to Grok led to a flood of antisemitic commentary from the chatbot this week that included praise of Adolf Hitler.

“We are aware of recent posts made by Grok and are actively working to remove the inappropriate posts,” the Grok account posted on X early Wednesday, without being more specific.

Some experts have tied Grok’s behavior to Musk’s deliberate efforts to mold Grok as an alternative to chatbots he considers too “woke,” such as OpenAI’s ChatGPT and Google’s Gemini. In late June, he invited X users to help train the chatbot on their commentary in a way that invited a flood of racist responses and conspiracy theories.

“Please reply to this post with divisive facts for @Grok training,” Musk said in the June 21 post. “By this I mean things that are politically incorrect, but nonetheless factually true.”

A similar instruction was later baked into Grok’s “prompts” that instruct it on how to respond, which told the chatbot to “not shy away from making claims which are politically incorrect, as long as they are well substantiated.” That part of the instructions was later deleted.

“To me, this has all the fingerprints of Elon’s involvement,” said Talia Ringer, a professor of computer science at the University of Illinois Urbana-Champaign.

Yaccarino has not publicly commented on the latest hate speech controversy. She has, at times, ardently defended Musk’s approach, including in a lawsuit against liberal advocacy group Media Matters for America over a report that claimed leading advertisers’ posts on X were appearing alongside neo-Nazi and white nationalist content. The report led some advertisers to pause their activity on X.

A federal judge last year dismissed X’s lawsuit against another nonprofit, the Center for Countering Digital Hate, which has documented the increase in hate speech on the site since it was acquired by Musk.

X is also in an ongoing legal dispute with major advertisers — including CVS, Mars, Lego, Nestle, Shell and Tyson Foods — over what it has alleged was a “massive advertiser boycott” that deprived the company of billions of dollars in revenue and violated antitrust laws.

Enberg said that, “to a degree, Yaccarino accomplished what she was hired to do.” Emarketer expects X’s ad business to return to growth in 2025 after more than halving between 2022 and 2023 following Musk’s takeover.

But, she added, “the reasons for X’s ad recovery are complicated, and Yaccarino was unable to restore the platform’s reputation among advertisers.”