Noam Shazeer, a vice president of engineering and co-lead of Google’s Gemini AI models, announced his departure to OpenAI on June 18. Google acquired Shazeer’s startup Character.AI for $2.7 billion in September 2024 to bring him back. He lasted 21 months.

The departure hit Alphabet’s stock immediately. Shares fell 7% as investors processed the loss of one of the company’s most senior AI researchers, according to Eciks.

The Transformer Paper and Its Author

Shazeer co-authored the 2017 paper “Attention is All You Need,” which introduced the Transformer architecture underpinning most modern large language models. He left Google in 2021 to found Character.AI, a consumer chatbot company. Google spent billions to win him back through an acquisition. OpenAI CEO Sam Altman welcomed him publicly, calling Shazeer “one of the people he had most wanted to work with,” per Eciks.

His expertise in model architecture and AI systems design made him a central figure in the race between OpenAI, Google, Anthropic, and Meta. Losing him to a direct competitor compounds Google’s challenge.

Two Departures in Three Days

Shazeer’s exit came days before John Jumper, a Nobel Prize-winning researcher at Google DeepMind, announced he was leaving for Anthropic. Jumper won the 2024 Nobel Prize in Chemistry for leading AlphaFold, the AI system that solved protein folding. He spent nearly nine years at DeepMind before his departure on June 19, as Eciks reported.

NCT covered Jumper’s departure on June 20. The back-to-back exits form a pattern: two of Google’s highest-profile AI researchers choosing competitors within the same week.

$180 Billion in Spending, Shrinking Talent Bench

Google has signaled massive investment in AI infrastructure. Alphabet announced in early June that it would raise $80 billion through equity offerings to fund AI capital expenditures, with total AI spending projected to reach $180 billion to $190 billion in 2026, according to Eciks.

D.A. Davidson analyst Gil Luria told Barron’s that while Google remains well-positioned overall, “the race at the frontier right now appears between Anthropic and OpenAI.” The observation lands differently when both companies just recruited Google’s top researchers.

The Retention Problem

The short tenure is the sharpest signal. Google did not lose Shazeer because it failed to recruit him. It recruited him at extraordinary cost, gave him a VP-level role co-leading its flagship model program, and still could not keep him for two years. Money alone, it appears, cannot hold talent in a market where OpenAI and Anthropic are both preparing for IPOs and offering researchers the chance to shape products at smaller, faster-moving organizations.

For agent builders relying on Gemini’s trajectory, the question is whether Google’s model development pace holds with its architecture lead walking out the door.