Nebius Group N.V. launched Nebius AI Cloud 3.1 on December 17, 2025, integrating next-generation NVIDIA Blackwell Ultra compute. This positions Nebius as the first global provider operating specific Blackwell Ultra systems on 800 Gbps NVIDIA Quantum-X800 InfiniBand, enhancing its full-stack AI cloud platform. Following an initial dip on December 17, 2025, Nebius shares rebounded significantly, closing up 14.56% on December 19, 2025, and another 4.21% on December 22, 2025, to $93.23. This reflects investor re-evaluation amid sustained demand for AI infrastructure, recent mega-deals with Microsoft and Meta, and analyst optimism despite capital intensity.