May 28 (Reuters) - Nebius Group's shares climbed 6.4% on Thursday after a fund run by former OpenAI employee Leopold Aschenbrenner disclosed a stake in the AI infrastructure firm.
The stock hit its highest in two weeks after the fund, named Situational Awareness, disclosed that it owned 12.41 million shares in the company, representing a roughly 5% stake worth $2.6 billion as of Wednesday, according to Reuters calculations.
The stake makes Situational Awareness the biggest shareholder of Amsterdam-based
Nebius, according to data compiled by LSEG, and marks a vote of confidence in the company as a key player in the AI infrastructure race.
Nebius, which was on investors' radar during the early stages of the AI boom, has quickly captured the market's attention. Its shares have risen more than 162% so far in 2026.
Earlier this month, Nebius reported a nearly eightfold rise in quarterly revenue.
Nebius has also been expanding through acquisitions. It announced a $643 million purchase of Eigen AI in May and an AI infrastructure supply agreement with Meta in March.
But with the stock trading at a rich valuation, the bar for further gains may be higher, and a rally of a similar magnitude may be difficult without some major catalysts.
D.A. Davidson analyst Gil Luria rated the stock "neutral" and said shares may see limited gains in the near term, in a note published earlier this month.
However, insatiable demand for AI computing power could boost Nebius, while investors searching for the next wave of AI winners could also flock to the company.
Situational Awareness managed $13.67 billion as of March 31, representing 148% growth from the end of 2025. Aschenbrenner was previously part of the "Superalignment" team at OpenAI.
The team, which worked to ensure AI stays aligned with human values, has been disbanded.
(Reporting by Niket Nishant in Bengaluru; Editing by Shinjini Ganguli)
