Key Takeaways
- • Situational Awareness, a hedge fund founded by former OpenAI researcher Leopold Aschenbrenner, disclosed a 5.6% stake in Nebius (NBIS) worth approximately $2.6 billion as of the Wednesday closing price, triggering a 12% premarket jump on Thursday.
- • The stake acquisition occurred after Nebius secured major cloud contracts with Microsoft and Meta, along with an equity investment from Nvidia and energy partnerships, positioning the company as a critical infrastructure play in AI infrastructure.
- • Nebius shares have surged 165% year-to-date and 475% over the past 12 months, with the stock approaching its highest level in over two weeks following the disclosure.
- • Situational Awareness's investment represents a significant endorsement from a specialized AI infrastructure-focused fund, elevating Nebius among the largest disclosed institutional shareholders alongside BlackRock (4.5% stake as of March 31).
- • The fund's total portfolio value has climbed to $13.7 billion as of Q1 2026, up 2.5x from $5.5 billion at the end of 2025, reflecting aggressive positioning around physical AI infrastructure including chips, data centers, power, and compute.
Summary
Nebius stock surged 12% in premarket trading on May 28 following disclosure that Situational Awareness, an AI infrastructure-focused hedge fund, has acquired a 5.6% stake in the cloud infrastructure company. The position, disclosed via 13G filing on Wednesday, comprises 12.4 million Class A shares valued at approximately $2.6 billion based on Wednesday's closing price. This marks a notable entry for the fund, as the stake did not appear in its most recent 13F filing covering March 31 holdings, indicating the acquisition occurred in the second quarter of 2026.
Situational Awareness was founded in 2024 by Leopold Aschenbrenner, formerly of OpenAI, and has built a specialized portfolio focused on the physical infrastructure underlying AI systems—including semiconductors, data centers, power infrastructure, and compute capacity. The fund's portfolio value has expanded dramatically to $13.7 billion as of Q1 2026, representing a 2.5x increase from $5.5 billion at year-end 2025. Aschenbrenner named the fund after his widely circulated essay on artificial superintelligence, establishing a clear investment thesis around critical infrastructure for advanced AI systems.
Nebius has gained substantial momentum recently through strategic partnerships and capital raises. The company has secured major cloud infrastructure contracts with both Microsoft and Meta, received an equity investment from Nvidia, and established energy partnerships with Bloom—positioning it as a central player in the race for AI compute capacity. These developments have driven the stock's exceptional performance: up 165% year-to-date and 475% over the trailing 12-month period as of May 28, 2026.
The Situational Awareness disclosure places the fund among Nebius's largest disclosed institutional shareholders, based on available filings. BlackRock remains the largest institutional holder at 4.5% of shares outstanding as of March 31, 2026. The stake signals conviction from a specialized investor focused specifically on AI infrastructure, validating Nebius's market positioning during a period of intense capital competition for AI-enabling assets. The stock opened at its highest level in over two weeks following the announcement.
Situational Awareness was founded in 2024 by Leopold Aschenbrenner, formerly of OpenAI, and has built a specialized portfolio focused on the physical infrastructure underlying AI systems—including semiconductors, data centers, power infrastructure, and compute capacity. The fund's portfolio value has expanded dramatically to $13.7 billion as of Q1 2026, representing a 2.5x increase from $5.5 billion at year-end 2025. Aschenbrenner named the fund after his widely circulated essay on artificial superintelligence, establishing a clear investment thesis around critical infrastructure for advanced AI systems.
Nebius has gained substantial momentum recently through strategic partnerships and capital raises. The company has secured major cloud infrastructure contracts with both Microsoft and Meta, received an equity investment from Nvidia, and established energy partnerships with Bloom—positioning it as a central player in the race for AI compute capacity. These developments have driven the stock's exceptional performance: up 165% year-to-date and 475% over the trailing 12-month period as of May 28, 2026.
The Situational Awareness disclosure places the fund among Nebius's largest disclosed institutional shareholders, based on available filings. BlackRock remains the largest institutional holder at 4.5% of shares outstanding as of March 31, 2026. The stake signals conviction from a specialized investor focused specifically on AI infrastructure, validating Nebius's market positioning during a period of intense capital competition for AI-enabling assets. The stock opened at its highest level in over two weeks following the announcement.
Go deeper than the headline
Research every firm in this story, track the ones that matter and get the daily briefing — free for 7 days.