Google
Alphabet shares plunged after two top AI researchers left Google for OpenAI and Anthropic within days.

Alphabet suffered its worst day on the stock market in more than a year on Monday as concerns mounted over its artificial intelligence strategy following the departure of two prominent researchers to rival companies.

Shares in the Google parent company closed down around 5%, erasing approximately $264 billion from its market value. The decline marked Alphabet's steepest one-day fall since May 2025 and left the company trailing other major technology stocks.

The sell-off came as investors reacted to a series of developments that have raised questions about Google's position in the increasingly competitive AI race.

Gemini Architect Leaves for OpenAI

The first blow arrived last week when Noam Shazeer, Google's Vice President of Engineering and co-lead of the Gemini AI models, announced that he was leaving the company to join OpenAI.

Shazeer is regarded as one of the key figures behind Google's latest AI efforts. His departure attracted attention because he had only returned to Google in 2024 after spending several years building Character.AI, a start-up he co-founded after leaving the company in 2021.

Google brought Shazeer and fellow researcher Daniel De Freitas back into its DeepMind division through a partnership with Character.AI. At the time, the move strengthened Google's efforts to compete with OpenAI and other AI developers. His latest exit comes only weeks after Google unveiled several major AI products at its annual I/O developer conference, including the Gemini 3.5 Flash model and the Gemini Spark AI agent. For investors, the timing could hardly have been worse.

DeepMind Veteran Departs for Anthropic

Concerns deepened on Friday when John Jumper, DeepMind Vice President and Engineering Fellow, announced that he would leave the company after nine years to join rival AI firm Anthropic. Jumper is one of the most respected researchers in artificial intelligence. In 2024, he shared the Nobel Prize with DeepMind chief Demis Hassabis for their work on AlphaFold.

The breakthrough system transformed biological research by predicting protein structures with remarkable accuracy. According to Google, AlphaFold has predicted more than 200 million protein structures, accelerating scientific research around the world. Jumper's departure means Google has now lost two highly visible AI leaders within a matter of days.

AI Spending Faces Fresh Scrutiny

The market reaction also reflected broader concerns surrounding the economics of artificial intelligence. Google has invested heavily in AI infrastructure, research, and product development as competition intensifies across the technology sector. According to CNBC, Alphabet has raised approximately $141 billion through debt and equity financing since October to support its AI ambitions.

Investors continue to assess whether such spending will translate into sustainable long-term returns. Those concerns gained additional momentum following comments made by Microsoft Chief Executive Satya Nadella in an interview with The Wall Street Journal published on Sunday. Nadella argued that the AI market was becoming increasingly commoditised and called for less dependence on what he described as AI giants.

His remarks highlighted a growing debate within the industry. If AI models become cheaper and easier to replace, companies may find it more difficult to maintain lasting competitive advantages despite significant investment.

Pressure Builds in the AI Race

Google remains one of the world's leading AI companies. Its DeepMind division continues to produce influential research, while Gemini remains central to Google's future product strategy. However, Monday's sharp market reaction demonstrated how closely investors are monitoring developments in artificial intelligence.

The departure of senior researchers does not automatically weaken Google's technological capabilities. Yet it arrives at a time when technology companies are competing aggressively for the engineers and scientists shaping the future of AI.

For Alphabet, the challenge now extends beyond launching new products. The company must also convince investors that its vast investment in artificial intelligence can deliver meaningful returns in a market that is becoming more crowded and increasingly competitive. As competition intensifies across Silicon Valley, the battle for talent may prove just as important as the battle for technology.

Writer's pick