By Adam Clark

Lumentum Holdings and Coherent were falling on Monday. A bad day for artificial-intelligence infrastructure stocks was compounded by news that prominent AI investor Leopold Aschenbrenner had dumped his holdings in the optical-networking companies.

Lumentum was down 11% and Coherent was dropping 6.6% in morning trading. Although those are only small dents in the huge gains the two companies have racked up in recent months, they are signs of some nervousness around AI hardware plays.

Sentiment was being hit both by high bond yields and news that Aschenbrenner's Situational Awareness firm exited its holdings in Lumentum and Coherent in the first quarter, according to regulatory filings released Monday. It also sold its stake in Tower Semiconductor, which was down 8% in morning trading.

Aschenbrenner briefly worked as a researcher at ChatGPT-developer OpenAI, before leaving and turning to stock-picking, with a focus on companies that stand to benefit from the development of AI technology. He named his firm Situational Awareness after the title of a lengthy essay he published in June 2024 arguing that effectively superhuman artificial intelligence could arrive as soon as 2027.

Lumentum and Coherent have benefited from a surge in Big Tech spending on AI infrastructure that has boosted their share prices. The companies make technology that allows AI processing chips to communicate with each other. Both companies have backing from Nvidia, which announced in March that it was investing $2 billion in both Lumentum and Coherent, along with multibillion-dollar purchase commitments with the two companies.

Lumentum stock has more than doubled since Barron's wrote positively about the company early in January, noting that Nvidia is adopting co-packaged optics -- integrating optical engines directly alongside its chips -- for its next-generation SpectrumX and QuantumX AI switches. Lumentum is the sole supplier of lasers for those switches.

Write to Adam Clark at adam.clark@barrons.com

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May 18, 2026 11:21 ET (15:21 GMT)

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