Nebius Surges 12% After Ex-OpenAI Researcher’s Fund Buys 5.6% Stake, May 28

Shares of NBIS jumped 12% in premarket trading on May 28 after Situational Awareness LP disclosed a 5.6% stake worth $2.6 billion. The hedge fund, founded by former OpenAI researcher Leopold Aschenbrenner, now owns 12.4 million Class A shares. The stake makes Nebius the fund’s largest holding. Nebius has gained 165% year-to-date on strong AI infrastructure demand.

Who Is Leopold Aschenbrenner and Why Does His Fund Matter

Leopold Aschenbrenner was hired to OpenAI’s Superalignment team in 2023 to ensure superhuman AI systems are safe. He was dismissed in 2024 for allegedly leaking internal information. He founded Situational Awareness shortly after, focusing on physical infrastructure for AI. The fund manages billions in assets and invests in chips, data centers, power, and compute capacity. Its portfolio value reached $13.7 billion as of Q1 2026, up 2.5x from $5.5 billion at year-end 2025.

What Nebius Does and Why It Attracts Big Money

Nebius is a Dutch cloud provider specializing in GPU infrastructure for AI model training. The company secured a $27 billion deal with Meta in March, providing $12 billion of dedicated capacity and up to $15 billion of additional compute over five years. Nebius also received a $2 billion investment from Nvidia in March. The company reported Q1 2026 revenue of $399 million, up 684% year-over-year. Adjusted EBITDA margin expanded to 32.45%.

The Stock’s Momentum and Valuation Concerns

Nebius stock is up 165% year-to-date and 475% over the past 12 months. The stock trades at a price-to-earnings ratio of 80.14 and a price-to-sales ratio of 56.93. Meyka rates the stock a B with a HOLD suggestion. The stock price sits at $227.37 on May 28. Analysts rate the stock a consensus Buy with 7 Buy ratings and 2 Hold ratings. However, the stock jumped 12% overnight on the Aschenbrenner disclosure, raising questions about entry timing after such a sharp move.

Power and Infrastructure Challenges Drive the Investment

Nebius faces Europe’s higher electricity costs compared to the U.S. The company announced a $2.6 billion deal with Bloom Energy last week to deploy fuel cell technology at U.S. data centers. Situational Awareness focuses on overcoming infrastructure bottlenecks in AI development, including energy constraints and computing power. The fund also holds stakes in Oracle, Nvidia, ASML, and Micron Technology. Its Nebius investment signals confidence in the company’s ability to scale AI infrastructure globally.

Final Thoughts

Nebius stock rallied 12% on the Aschenbrenner stake disclosure, but the stock trades at 80x earnings and has already gained 475% in 12 months. With Meyka rating the stock B and analysts targeting Buy, the data suggests limited near-term upside after today’s gap higher.

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The content shared by Meyka AI PTY LTD is solely for research and informational purposes.  Meyka is not a financial advisory service, and the information provided should not be considered investment or trading advice.