Nebius Group shares climbed more than 10% in premarket trading on Thursday after a regulatory filing showed Situational Awareness, an investment vehicle run by Leopold Aschenbrenner, had become the company's largest shareholder.
The filing disclosed a 5.6% stake in Nebius held by Situational Awareness, a position the filing valued at almost $2.6 billion as of Wednesday. That ownership level positions the fund as the single largest holder of Nebius stock and sent the shares toward their strongest opening in over two weeks.
Situational Awareness reported assets under management of $13.67 billion as of March 31. The filing noted that figure represented 148% growth from the end of 2025. Aschenbrenner, who manages the fund, previously served on the "Superalignment" team at OpenAI - a group the article states has since been disbanded.
The timing of the stake disclosure coincides with a recent operating update from Nebius. Earlier this month the company reported a nearly eightfold increase in quarterly revenue. The combination of a revenue surge and a large institutional stake appears to have contributed to the premarket rally.
Market participants monitoring the stock observed the premarket move put Nebius on track to open at its highest levels in more than two weeks. The filing and the revenue report together form the factual basis for the notable intraday price action.
Contextual details
- Situational Awareness is run by Leopold Aschenbrenner, a former member of OpenAI’s Superalignment team.
- The fund disclosed ownership of 5.6% of Nebius, valued at nearly $2.6 billion as of Wednesday.
- Situational Awareness managed $13.67 billion as of March 31, a 148% increase from the end of 2025.
- Nebius reported a nearly eightfold rise in quarterly revenue earlier this month.
The facts presented here are based on the recent filing and the company’s revenue disclosure. There are no additional reported details in the filings about the fund’s strategy for the stake or any operational changes at Nebius tied directly to the investment.