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

Leopold Aschenbrenner, a former OpenAI researcher, acquired a 5.6% stake in Nebius (NBIS), the cloud-based AI infrastructure company, through his Situational Awareness fund. Despite the stock's 170% rally this year, Aschenbrenner's investment aligns with his thesis that physical AI infrastructure—data centers, chips, and power grids—will be the ultimate bottleneck for AI growth. Nebius, formerly Russia's Yandex, has surged with major deals from Meta and Microsoft, with analysts projecting 242% revenue CAGR through 2028.