Nebius Stock Is Up 170% in 2026, and Leopold Aschenbrenner Just Bought a 5.6% Stake. Here's Why

Leopold Aschenbrenner, a prominent German AI researcher and investor who previously worked at OpenAI, recently acquired a 5.6% stake in the cloud-based AI infrastructure company Nebius (NASDAQ: NBIS) through his Situational Awareness fund.

That purchase might seem surprising, since Nebius' stock has already rallied nearly 170% this year and doesn't look like a bargain at 19 times this year's sales. Let's see why Aschenbrenner invested in Nebius -- and if it could soar even higher through the end of the year.

Image source: Getty Images.

A high-growth AI infrastructure play

Nebius was formerly Yandex, which owned Russia's largest search engine. But in 2022, the sanctions against Russia forced Yandex to divest its Russian assets, relocate to the Netherlands, and rebrand itself as Nebius, a cloud-based AI infrastructure company.

As Nebius, it provides customized AI services for the data training, edtech, and robotics markets. It also integrates popular managed services, such as Kubernetes, into its data centers. That makes it more of a full-stack AI infrastructure services provider than CoreWeave (NASDAQ: CRWV), which mainly helps companies process GPU-intensive tasks.

Neocloud companies, like Nebius and CoreWeave, are growing rapidly as streamlined, AI-focused alternatives to traditional cloud infrastructure platforms like Amazon Web Services (AWS) and Microsoft Azure. They can generally process AI tasks faster and more cheaply than those larger cloud platforms.

After restructuring itself as an AI infrastructure company, Nebius' revenue surged 351% to $530 million in 2025. From 2025 to 2028, analysts expect its revenue to grow at a 242% CAGR to $21.2 billion and achieve profitability in the final year. That explosive growth should be fueled by its two massive deals with Meta and Microsoft, as well as its future multi-billion-dollar deals with other hyperscalers as the AI market expands.

Why is Nebius still a promising investment?

Aschenbrenner's Situation Awareness fund mainly invests in companies building the physical infrastructure layer of AI rather than makers of chatbots or generative AI apps. Its investment thesis originates from Aschenbrenner's self-published essay -- Situational Awareness: The Decade Ahead -- which argues that the ultimate bottleneck for the AI market's growth won't be algorithms, but rather the physical constraints of data centers, chips, and power grids.

Aschenbrenner's investment in Nebius clearly fits into that strategy. That's probably why Nvidia -- the world's leading data center GPU maker -- also took stakes in Nebius and CoreWeave over the past few years. Nebius' stock will likely remain volatile in this choppy market, but it could be a great long-term play on the growing neocloud market.

Leo Sun has positions in Amazon and Meta Platforms. The Motley Fool has positions in and recommends Amazon, Meta Platforms, Microsoft, and Nvidia. The Motley Fool has a disclosure policy.