Leopold Aschenbrenner Discloses $2.6B Stake in Nebius via 13G Filing

Leopold Aschenbrenner's Situational Awareness Fund filed a Schedule 13G on May 27 disclosing a 12.4 million share position in Nebius (NASDAQ: NBIS), representing a 5.6% stake valued at approximately $2.6 billion at the stock's last closing price of $208.37. The disclosure makes the fund one of the largest institutional investors in the AI infrastructure company. Aschenbrenner, a former OpenAI research team member, structured the fund around AI compute, energy, and semiconductor investments. The filing triggered a 12% pre-market rally in NBIS stock on May 28.

Filing Details

The May 27 Schedule 13G filing lists 12.4 million Nebius shares held by Situational Awareness Fund. At $208.37 per share, the position totals $2.6 billion, making it the fund's largest disclosed holding. The 5.6% ownership stake crosses the SEC's 5% threshold requiring public disclosure within 10 days of acquisition.

Portfolio Context

Nebius represents the fund's largest position among disclosed holdings. The portfolio's second-largest position is Bloom Energy (NYSE: BE) at $878.7 million, followed by Sandisk (NASDAQ: SNDK) at $724.4 million and CoreWeave (NASDAQ: CRWV) at $556.1 million. Previous 13F filings showed positions in Bitcoin mining companies including Iren Limited (NASDAQ: IREN), Core Scientific (NASDAQ: CORZ), and CleanSpark (NASDAQ: CLSK). The fund also holds semiconductor and AI supply chain stocks including AMD (NASDAQ: AMD), Intel (NASDAQ: INTC), and Micron (NASDAQ: MU).

Market Reaction and Company Fundamentals

Nebius stock rose 12% in pre-market trading on May 28 following the disclosure. The company reported Q1 2026 revenue of $399 million, up 684% year-over-year. Nebius raised its 2026 contracted power capacity guidance from 3 GW to over 4 GW. Citizens and DA Davidson increased their Nebius price targets following the Q1 results, citing the company's growth profile.