Alphabet shares fell sharply on Monday after Google DeepMind researcher and Nobel Prize winner John Jumper announced he was leaving the company to join Anthropic.

The stock dropped as much as 7.2% during the session, marking its steepest intraday decline since February. The move came amid broader weakness across major technology stocks, with Amazon, Meta and Microsoft also falling.

Jumper spent nearly nine years at Google DeepMind and played a central role in developing AlphaFold, an artificial intelligence system that predicts protein structures. The work earned Jumper and DeepMind CEO Demis Hassabis the 2024 Nobel Prize in Chemistry.

His departure marks the second major loss from Google’s AI organization in less than a week. Noam Shazeer, a vice president of engineering and one of the leaders behind Gemini, recently announced he was leaving Google to join OpenAI.

Google brought Shazeer back to the company in 2024 through a deal reportedly valued at about $2.7 billion after he previously left to cofound Character AI.

The departures come as Anthropic and OpenAI compete aggressively with Google for AI talent and corporate customers. Both companies have gained momentum through coding tools, an area where Google has struggled to build stronger adoption among businesses, according to former employees.

Jumper was also involved in Google’s AI coding development efforts before announcing his move to Anthropic. His role at the company has not yet been disclosed.

The selloff extended beyond Alphabet, with most Magnificent Seven stocks trading in the red on Monday. Amazon fell nearly 5%, while Meta and Microsoft declined more than 2%.