Jeff Dean (TensorFlow/TPU architect) leaves Google to start company; Demis Hassabis steps down as Google DeepMind CEO

Google's legendary AI researcher Jeff Dean has departed to launch a startup, striking a jolt through the company. The exodus also includes Quoc Le and Oriol Vinyals, both towering figures in the academic AI community.

The news arrives alongside a broader leadership restructuring: Demis Hassabis has stepped down as CEO of Google DeepMind to assume the role of DeepMind Chairman and Chief Scientist of Alphabet, refocusing on long-term AGI strategy and accelerating scientific breakthroughs. Hassabis's operational responsibilities will transfer to his longtime deputy Koray Kavukcuoglu, who assumes the position of Senior Vice President of Google DeepMind and will report directly to Google CEO Sundar Pichai.

The announcements triggered an immediate 4% drop in Google's stock price, erasing $186 billion in market value—approximately 1.34 trillion RMB.

Dean's new venture, Discovery Loop, is structured as a public-benefit corporation with a mission to automate machine learning, scientific research, and engineering. The four departing leaders collectively represent Google's two most vital technical pillars over the past two decades: large-scale computational infrastructure and modern AI.

Despite the magnitude of this departure, the separation remains cordial. Pichai publicly blessed the move, revealing that Google has invested in Discovery Loop and will serve as a cloud partner. According to Wired, after Dean and his colleagues submitted their resignations, Pichai attempted to retain them, hoping they would keep their Google badges—but the four ultimately prioritized the freedom and independence of founding a startup.

Discovery Loop's funding and valuation remain undisclosed, though any single member of this four-person team commands seismic significance in the field. That all four are departing together marks arguably the most formidable startup founding team in the current landscape.

The announcement now risks triggering a cascading exodus, as additional Google talent may follow from a company struggling amid LLM delivery pressures and intense talent competition.

The departure is particularly striking given recent turnover among Gemini's leadership. All three principal architects—Jeff Dean, Oriol Vinyals, and Noam Shazeer—have now exited Google.

Hassabis's transition expands his remit while reducing direct operational control. Beyond DeepMind's day-to-day operations, he will oversee long-term AGI strategy, societal impact, scientific research, and Isomorphic Labs—the drug-discovery company previously spun out from DeepMind. Hassabis will now engage directly with Pichai on global, strategic AGI questions, broadening his scope while diminishing hands-on execution responsibility.

Koray Kavukcuoglu inherits Hassabis's previous portfolio, including Gemini model and application development, frontier AI research, and direct reporting to Pichai.

Context amplifies the significance: Google faces mounting pressure from OpenAI and Anthropic in foundational model competition, compounded by delays to Gemini's flagship release. On June 18, Noam Shazeer—a core Gemini architect—departed for OpenAI. On June 19, Hassabis's longtime collaborator and Nobel laureate John Jumper joined Anthropic. On June 24, two additional Gemini core contributors—Jonas Adler (AI programming) and Alexander Pritzel (pretraining)—announced they were joining Anthropic.

The tension is acute: large language model competition demands tighter, faster organizational execution, yet next-generation breakthroughs often depend on elite researchers wielding substantial autonomy. Codex's lead recently disclosed that Google possessed ChatGPT-equivalent technology a full year before its public release, yet "Google was too risk-averse to deploy it, and DeepMind was prohibited from shipping products that might cannibalize Google's core business."

Now, a Google legend departs—not in retirement, not after measured success, but amid an ongoing wave of turbulence, ceding the field to rivals.