This article first appeared on GuruFocus .

Nebius Group N.V. ( NASDAQ:NBIS ) rose 6.80% intraday after the company announced an agreement to acquire Eigen AI, an inference and model optimization startup, in a deal valued at approximately $643 million in cash and Class A shares, priced on Nebius's 30-day weighted average stock price as of signing. Eigen AI's technology is built to extract more throughput from each GPU in production, which translates directly into better performance and lower cost per inference for customers. After close, its optimization layers will be integrated into Nebius Token Factory, the company's managed inference product spanning all major open-source models.

Eigen AI's co-founders, Ryan Hanrui Wang and Wei-Chen Wang, are alumni of MIT's HAN Lab, and their work is embedded across the industry. Wei-Chen's Activation-aware Weight Quantization research won the MLSys 2024 Best Paper Award. A third co-founder, Di Jin, contributed to post-training for Meta's Llama 3 and Llama 4. The team will anchor a new Bay Area engineering presence for Nebius. We are operating in a capacity-scarcity world where AI builders need optimized inference and infrastructure scale, said Roman Chernin, co-founder and Chief Business Officer of Nebius.

The two companies had already jointly optimized open-source model deployments that ranked among the fastest on Artificial Analysis, giving the integration a running start. Nebius reports Q1 2026 results on May 13, with the stock up over 70% year to date and over 490% in the past twelve months.