Leopold Aschenbrenner, known as one of the youngest billionaires and a former member of the OpenAI research team, has just disclosed one of his largest stock positions yet.
According to the latest Schedule 13G filings submitted on May 27 by Aschenbrenner’s Situational Awareness Fund, the young investor holds 12.4 million shares in Nebius (NASDAQ: NBIS).
The position represents a 5.6% stake, which makes the fund one of the largest institutional investors in the artificial intelligence (AI) company.
At the stock’s last closing price of $208.37, the position is worth around $2.6 billion, a fact that sent NBIS stock up 12% in pre-market trading.
Nebius becomes Leopold Aschenbrenner’s largest holding
Currently, Nebius stands as the fund’s largest holding. The other notable positions include various AI infrastructure, energy, and compute bets.
For example, the portfolio’s second-largest disclosed position is Bloom Energy (NYSE: BE), worth $878.7 million. Other comparable investments include Sandisk (NASDAQ: SNDK), at $724.4 million, and CoreWeave (NASDAQ: CRWV), at $556.1 million.
Also worth mentioning is Aschenbrenner’s exposure to Bitcoin (BTC) via mining companies and the energy sector. For instance, his previous 13F filings disclosed positions in Iren Limited (NASDAQ: IREN), Core Scientific (NASDAQ: CORZ), and CleanSpark (NASDAQ: CLSK).
His other noteworthy bets include various semiconductor and AI supply chain names, most notably AMD (NASDAQ: AMD), Intel (NASDAQ: INTC), and Micron (NASDAQ: MU).
Nebius stock surges
As mentioned, Nebius’s stock surged 12% in pre-market trading on May 28, following the disclosure. The reason for the explosive rally likely lies in the fact that Nebius had already enjoyed strong momentum.
Indeed, the company reported Q1 2026 revenue of $399 million, up 684% year-over-year, while raising its 2026 contracted power capacity guidance from 3 GW to over 4 GW.
Accordingly, firms such as Citizens and DA Davidson have increased their Nebius price targets, arguing the company’s ‘hyper-growth’ profile offers a key competitive advantage.
In other words, Aschenbrenner’s endorsement was only anothe thumbs-up in a series of bullish forecasts and ‘Buy’ recommendations that have come in this year.
Featured image via Shutterstock
