Nebius Group NV (NASDAQ:NBIS) has become one of 2025’s most jaw-dropping AI success story, and perhaps its biggest puzzle. The mid-cap AI cloud infrastructure firm has soared around 513% over the past 12 months, and 330% this year, vaulting from relative obscurity into Wall Street’s favorite speculative obsession. Yet as the stock’s valuation rockets past 29 times projected 2026 sales, ETF managers are asking the billion-dollar question: how much AI is too much AI?
The Amsterdam-based firm has ridden the AI euphoria harder than almost any peer, fueled by a blockbuster $17.4 billion AI infrastructure deal with Microsoft Corp (NASDAQ:MSFT) and a 625% year-over-year revenue jump last quarter. Its new enterprise platform, AI Cloud 3.0 – Aether, promises supercomputer-grade performance for regulated industries.
