Nebius jumps 11% after ex-OpenAI researcher's fund reveals 5.6% stake

Nebius Group NV shares surged in extended trading Wednesday after Leopold Aschenbrenner's Situational Awareness hedge fund disclosed a 5.6% stake in the AI infrastructure company, adding a high-profile backer to one of the year's best-performing neocloud stocks.

"AI infrastructure is the most important bottleneck in the scaling race, and Nebius has built one of the most capital-efficient platforms to address it," Aschenbrenner, a former OpenAI researcher and founder of Situational Awareness, said in the filing.

The fund reported beneficial ownership of approximately 12.41 million shares of Nebius, a Netherlands-based company that provides cloud computing infrastructure for AI workloads. Situational Awareness has grown to $13.7 billion in assets under management from $225 million in under two years, according to its most recent 13F filing, with several of its top holdings returning between 100% and 800%.

Aschenbrenner rose to prominence after publishing a 165-page AI manifesto that identified multiple bottlenecks in AI scaling years in advance. His fund's stake in Nebius signals conviction in the neocloud model, which offers specialized GPU clusters for AI training and inference — a market that has attracted increasing institutional capital as hyperscalers race to secure compute capacity.

NBIS shares traded at $232.48 in after-hours trading, up 11.47% from Wednesday's close of $227.19. The stock has more than tripled over the past 12 months as demand for AI compute infrastructure has outpaced supply. The disclosure positions Situational Awareness as one of Nebius's largest institutional holders. Investors will watch for any additional 13D filings or activist engagement from the fund in coming weeks.

This article is for informational purposes only and does not constitute investment advice.