Billionaire Stephen Mandel Just Loaded Up on This Incredible Artificial Intelligence (AI) Stock Up Nearly 200% in 2026

Billionaire Stephen Mandel, known for his successful track record, has made a significant investment move in Q2 by adding a new stock to his portfolio, making it his largest holding. This move is significant as it signals his confidence in the company's growth potential. The stock in question is Nebius (NASDAQ: NBIS), a relatively small player in the AI industry compared to giants like Nvidia.

Nebius' stock has surged nearly 200% in 2026, a performance that has caught the attention of Mandel and other investors alike. Despite a minor setback at the end of July, Nebius' growth continued throughout the summer, emerging as one of the top-performing stocks of the year. The company operates in the neocloud space, providing AI-focused cloud computing services.

Nebius' growth is fueled by the global shortage of AI computing power, and the company's status as a preferred partner of Nvidia gives it a competitive edge. Nebius has signed agreements with major AI hyperscalers to rent computing power, leading to impressive revenue growth. Analysts project a 523% growth for the second half of 2026 and a 258% growth for 2027.

Despite Nebius' stock tripling in 2026, it is still considered a phenomenal investment opportunity by Mandel and other experts.