Apple has kept a low profile in the artificial intelligence arms race. But now, a major talent loss is raising fresh questions about whether the iPhone maker is falling behind.

According to Bloomberg, Meta has hired Ruoming Pang, a high-level engineer who led Apple’s foundation models team. Pang, a former Google veteran and key architect behind the large language models (LLMs) powering Apple Intelligence, will now join Meta’s elite AI unit focused on building superintelligent systems.

His exit is a significant blow for Apple, especially at a time when the company is trying to convince the public and developers that it’s serious about generative AI. He was in charge of the team of roughly 100 engineers building the foundational technology behind Apple Intelligence, the suite of AI features recently announced at the company’s WWDC event.

On his LinkedIn page, Pang described his role as leading the team that develops the foundation models that power Apple Intelligence. Think of foundation models as the base engine for AI. These massive, complex models, also known as Large Language Models (LLMs), are trained on vast amounts of data and can be adapted to perform a wide range of tasks, from summarizing your emails to generating images. Pang’s team was responsible for every aspect of these models, from the training framework (AXLearn) and inference optimization (making the AI run efficiently on your device) to its multi-modal capabilities (the ability to understand both text and images).

Just last month, Pang celebrated his team’s work in a LinkedIn post following Apple’s developer conference. “At WWDC we introduce a new generation of LLMs developed to enhance the Apple Intelligence features,” he wrote. “I’m very excited about the progress we have made since last year and would like to take this opportunity to thank our team and collaborators. It has been a true privilege to work with you all!”

Pang joined Apple in 2021 after a 15 year career at Google. His departure now raises serious questions about Apple’s ability to retain top talent as it tries to play catch up in the AI arms race.

Meanwhile, Mark Zuckerberg and Meta are not just participating in the talent war; they are its most aggressive combatants. In a relentless push to build what he calls Artificial General Intelligence (AGI), or “superintelligence”—AI systems that can reason and think at or above human levels—Zuckerberg has been personally courting top researchers from across the industry. Meta is reportedly offering multi million dollar compensation packages to lure talent from rivals, particularly OpenAI.

This “hiring spree” has seen Meta assemble a dream team of AI pioneers, including former GitHub CEO Nat Friedman and Scale AI CEO Alexandr Wang. By convincing Pang to leave Apple, Zuckerberg has shown that no company is safe from his talent raid.

The move comes at a vulnerable moment for Apple. The company has faced internal debate over whether to rely on its in house models or strike deeper partnerships with third parties like OpenAI for future versions of Siri. This uncertainty has reportedly impacted morale within the AI division, and Pang’s exit could trigger a wider exodus of talent.

For Apple, losing the mind behind its core AI models is a critical setback. For Meta, it’s another high profile victory in its audacious, high stakes quest to dominate the next era of computing.

Apple did not immediately respond to a request for comment.