Alphabet shares fell as much as 7% on Monday, the company's worst single-session decline in more than a year, after two of Google's most prominent artificial intelligence researchers announced departures to rival laboratories within 24 hours of each other. The selloff erased approximately $269 billion in market capitalization, the largest one-day dollar loss in Alphabet's history, bringing the stock to around $347 per share before a partial recovery brought it to the $367 range.
The departures began last Wednesday when Noam Shazeer, a vice president of engineering and co-lead of Google's Gemini AI model family, announced he was leaving for OpenAI. The move carries layered significance: Shazeer is a co-author of the landmark 2017 paper 'Attention Is All You Need,' which introduced the Transformer architecture that underpins virtually every major large language model in use today, including ChatGPT, Gemini, and Claude. Google had paid $2.7 billion in September 2024 to reacquire him through its acquisition of his startup Character.AI — making his exit less than two years later a costly talent-retention failure by any measure. At OpenAI, Shazeer is expected to lead AI architecture research as the company prepares for a potential public listing.
The second blow arrived Friday when John Jumper, a DeepMind vice president, engineering fellow, and Nobel Prize laureate, announced he was joining Anthropic after nearly nine years at the lab. Jumper shared the 2024 Nobel Prize in Chemistry alongside DeepMind CEO Demis Hassabis for his work on AlphaFold2, the protein-structure prediction system that has generated more than 200 million predictions and is widely considered one of the most consequential scientific applications of artificial intelligence to date. Hassabis publicly thanked Jumper and said AlphaFold had 'changed the world.'
The back-to-back exits struck at the heart of investor confidence in Google's AI competitiveness at a moment when that confidence was already under strain. Alphabet has committed to $180 billion to $190 billion in AI capital expenditure for 2026 — roughly six times the $31 billion it spent on capex in 2022, and double the $91.4 billion deployed in 2025. To fund the buildout, the company raised $84.75 billion through equity offerings in early June, including a $10 billion investment from Berkshire Hathaway. At that scale, the question of who is directing the research that will determine whether those investments generate returns has become a first-order valuation question, not a personnel footnote.
D.A. Davidson analyst Gil Luria, who carries a Neutral rating on the stock, was direct: 'The race at the frontier right now appears to be between Anthropic and OpenAI,' he said, even as Alphabet reported 82% earnings growth in its most recent quarter and Google Cloud revenue surged 63% to $20 billion. IG chief market analyst Chris Beauchamp echoed the concern: 'In the war for dominance in AI, key figures like these are pearls of great price, and Alphabet's inability to hold on to this particular gem, combined with its eye-watering spending plans, is taking its toll.'
The majority of Wall Street analysts still rate the stock a Buy or equivalent, with Morgan Stanley, JP Morgan, Barclays, and Goldman Sachs all maintaining bullish ratings as recently as mid-June. The consensus is that a single quarter's talent exits do not fundamentally alter a company with Google Search, YouTube, Google Cloud, and the Waymo autonomous vehicle unit generating tens of billions in annual free cash flow. But the market's reaction on Monday suggests investors are applying a steeper discount than analysts to the risk that losing the architects of Gemini and AlphaFold weakens long-term positioning in the models race.
Alphabet shares were down an additional 2% in premarket trading Tuesday as the market digested the news alongside a broader tech selloff, leaving the stock down approximately 5% over the preceding three sessions.