Demis Hassabis is stepping down as CEO of Google DeepMind to become chairman of the unit and chief scientist of Alphabet, effective August 5, 2026. Jeff Dean is leaving Google after 27 years to co-found an AI startup called Discovery Loop.

Koray Kavukcuoglu will become senior vice president of Google DeepMind and report to Alphabet CEO Sundar Pichai. Kavukcuoglu will oversee Gemini model development and lead the development of Gemini 4.

Hassabis wrote to staff that he believes artificial general intelligence is close at hand. "I’ve decided that now is the right time for me to hand over my day-to-day operational responsibilities at GDM, so that I have the time and space to focus on the big picture and help influence what is to come to the best of my ability," Hassabis said.

"As you’ve heard me say many times, I’ve always believed the No.1 application of AI should be to improve human health." He added, "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." Hassabis will continue to lead Alphabet’s Isomorphic Labs, the company's AI drug discovery unit.

Alphabet shares fell around 5% on the news of the leadership changes. Google stock fell nearly 4% on the news of the leadership changes.

Pichai addressed Dean's departure in an internal memo. "After an incredible 27-year run, Jeff Dean is at a moment where he wants to try something new, and we’re excited to support him in that," Pichai said.

Dean joined Google in 1999 and was the company's 30th employee. He played a foundational role in the development of key technologies like TensorFlow and JAX. Dean is co-founding Discovery Loop with Sanjay Ghemawat, Oriol Vinyals, and Quoc Le.

Discovery Loop is a public benefit corporation focused on using AI to automate research in fields like chip design, biology, drug discovery, and material design. The startup aims to automate machine learning, science, and engineering research to accelerate discoveries and progress. Discovery Loop intends to build systems to tackle the 14 National Academy of Engineering Grand Challenges and enable the parallel execution of thousands of experiments to solve bottlenecks in science and engineering. "By fundamentally accelerating how engineering and scientific discovery are conducted, we can deliver the benefits of transformative technologies to the world far sooner," Dean said in a joint statement.

Alphabet is a founding investor in Discovery Loop and will supply cloud compute to the startup. Radical Ventures and Khosla Ventures are co-leading the initial funding round for Discovery Loop. Kleiner Perkins, Lightspeed, and Doerr Capital participated in the funding round. Jordan Jacobs of Radical Ventures will join the board of Discovery Loop.

Hassabis co-founded DeepMind, which Google purchased in 2014 for £400 million. In 2023, Alphabet announced the merger of Google Brain and DeepMind into a single unit called Google DeepMind, with Hassabis leading the combined team. Hassabis shared the 2024 Nobel Prize in chemistry for his AlphaFold work, which revolutionized protein structure prediction. He has been a UK Government AI Adviser since at least 2020, providing strategic guidance on AI policy and development in the United Kingdom.

Vinyals is VP of research at DeepMind and was technical lead on Gemini until August 2026, along with Dean. Le is a cofounder of Google Brain. Kavukcuoglu previously worked at DeepMind and contributed to the development of key AI models including AlphaFold and AlphaGo.

Gemini 3.5 Pro is months behind its original June launch target. Noam Shazeer left Google for OpenAI, and John Jumper left Google for Anthropic.

The simultaneous departure of two central figures in Alphabet's AI strategy marks a restructuring of the company's research leadership. Hassabis's move to chief scientist shifts his focus from daily operations to high-level strategy and health applications through Isomorphic Labs. Dean's exit after 27 years removes one of Google's earliest engineers and a key architect of its machine learning infrastructure.

Alphabet's investment in Discovery Loop indicates a strategy to support AI-driven scientific breakthroughs through external startups while maintaining a commercial relationship via cloud compute services. The leadership changes occur as Google faces delays in its Gemini model rollout and competition for AI talent, with recent departures to rivals including OpenAI and Anthropic.

Why It Matters

The simultaneous departure of two central figures in Alphabet's AI strategy marks a restructuring of the company's research leadership. Hassabis's move to chief scientist shifts his focus from daily operations to high-level strategy and health applications through Isomorphic Labs. Dean's exit to co-found Discovery Loop, backed by Alphabet as a founding investor, signals a corporate pivot toward automating scientific discovery outside traditional business units. These changes occur as Gemini 3.5 Pro faces delays and follows recent exits of other key researchers to rival firms.