The shakeup comes during a pivotal juncture for Google DeepMind: the flagship version of its latest Gemini model remains unreleased despite a planned June launch, sparking investor and industry concerns that Google is ‌falling behind its rivals Anthropic and OpenAI, each of which scooped up a star Google AI staffer this summer.

Shares of Alphabet fell 4% after the news.

Hassabis, a Nobel Prize recipient, will take the newly created title of Alphabet’s chief scientist and transition from being Google DeepMind CEO to being its chairman, he said in a memo to staff.

He cited the closeness of artificial general intelligence (AGI), an advanced state of AI in which computers in essence become as smart as humans, as the impetus for his role change.

“(Hassabis) and I have been long discussing a role that allows ​him to put his full attention on actively shaping the future of AGI,” Alphabet chief Sundar Pichai said in a separate company-wide memo.

“It’s work that is vitally important to Alphabet and humanity, and I can’t imagine ​a better person than Demis to do it.”

Koray Kavukcuoglu, the unit’s chief technology officer, will assume day-to-day responsibilities.

He will hold the title of senior vice president, rather than CEO, ⁠of the business unit, in addition to his parallel role as Alphabet’s chief AI architect.

Dean, Sanjay Ghemawat, Oriol Vinyals and Quoc Le — some of Google’s most famous and lauded AI and engineering leaders — left the company to launch a startup called Discovery ​Loop, which will focus on researching breakthroughs in machine learning, science and engineering.

The startup is structured as a public benefit corporation.

Alphabet did not provide any details on what precipitated the moves or their coincident timing.

As Reuters detailed in a report last ​year, some people who have worked with Hassabis said he put scientific pursuits often ahead of making money for Google.

The London-born scientist targeted a Nobel Prize as a business objective for DeepMind, three people familiar with the effort said.

He worked against other efforts, insiders previously said, that could have meant new revenue for Alphabet or a better footing in the AI race.

Allies inside Google rejected the notion that he was too focused on long-term science or gave short shrift to the business.

Senior leaders in Google Cloud, the company’s main AI revenue ​engine, cheered Kavukcuoglu’s takeover on Wednesday as welcome news for advancing commercialisation efforts, according to a source with direct knowledge.

Kavukcuoglu had already been more directly involved than Hassabis in collaborations between DeepMind and Cloud, and his appointment as head of the ​AI lab was expected to steer Gemini towards a more product-oriented direction, the source said.

Hassabis will explore research and strategy related to societal impacts of AGI and will have few direct reports, an Alphabet spokesperson told Reuters.

In his company memo, Hassabis touted the “great progress” ‌on Google’s AI ⁠models, including an unreleased upgrade called Gemini 4.

He also said in his memo that he would spend more time with Isomorphic Labs, a drug discovery company that spun out of DeepMind, which he founded and remains CEO of.

“I’ve always believed the No. 1 application of AI should be to improve human health,” he said.

“It’s time for AI to prove its unequivocal value to the world, and what better way to demonstrate that than to help finally cure diseases like cancer.”

Brain drain

Dean and Hassabis were considered the two leading AI figures at Google for years before the field became the centre of technological innovation.

Hassabis co-founded DeepMind in 2010 and continued to run the lab from London after selling it to Google for around $650 million in 2014.

Dean in 2011 co-founded ​Google Brain, a US-based unit he led that researched AI ​separately from Hassabis’ team.

By then, he was ⁠already a revered figure inside Google known for his collaboration with Ghemawat on many of the landmark infrastructure projects that still power the company today.

In 2023, after the launch of OpenAI’s ChatGPT caught Google off guard, Pichai announced the merger of DeepMind and Google Brain into a new organisation called Google DeepMind.

Hassabis was appointed its CEO and Dean its chief scientist.

Until recently, ​Dean, Vinyals and Noam Shazeer had co-led development of Gemini.

Under their stewardship, Google released Gemini 3 last November, which the industry widely saw as closing the gap with leading ​models from Anthropic and OpenAI.

But subsequent ⁠advances from those rivals, as well as momentum for cheaper Chinese open-source models, have set Google on the defensive.

At Google’s annual developer conference in May, Pichai and other Google leaders touted Gemini’s cost advantage, rather than its state-of-the-art capabilities.

Shazeer left for OpenAI in June, less than two years after Google paid billions to hire him and a team of his researchers away from the startup he led.

The same week, senior research scientist John Jumper, who won a Nobel Prize alongside Hassabis in 2024, said he would join Anthropic.

Vinyals, Le ⁠and former OpenAI ​chief scientist Ilya Sutskever coauthored a 2014 research paper that became foundational to modern AI research by establishing the concept that scaling up data to “pre-train” ​AI systems would send them to new heights.

“Google has a deep bench of talent, but losing these four individuals will leave a mark for some time.

Getting innovation and execution back online is not going to be easy, and losing key contributors won’t make it any better,“ said Brian Mulberry, ​chief market strategist for Zacks Investment Management.

Discovery Loop received investment from Google and also entered into a partnership with its cloud division to provide computing capacity.