Nebius Acquires AI Model Optimization Startup Eigen AI for $643M

Quick Facts

• Nebius agreed to acquire Eigen AI for $643 million in cash and stock, adding AI model optimization technology to its platform
• Eigen AI’s software optimizes open-source models to achieve up to 10x cost reduction through improved speed and hardware efficiency
• The deal follows Nebius’s remarkable growth from $11.4 million revenue in Q1 2024 to $227.7 million in Q4 2025

Nebius announced Friday it will acquire AI model optimization startup Eigen AI for approximately $643 million, marking the second acquisition in recent months as the AI cloud company expands its capabilities.

The deal includes $98 million in cash plus about 3.8 million shares of Class A stock. The transaction value is based on Nebius’s 30-day weighted average stock price and is subject to customary conditions including antitrust clearance.

Eigen AI was founded in 2025 by MIT graduates Ryan Hanrui Wang, Wei-Chen Wang, and Di Jin. The company develops software that optimizes open-source AI models by replacing default kernels with custom modules that deliver better performance. Their technology can achieve up to 10x cost reduction through improved speed and hardware efficiency.

The founding team brings significant credentials from MIT’s HAN Lab. Wang’s Sparse Attention work is the most-cited HPCA paper since 2020, while Wei-Chen received the MLSys 2024 Best Paper Award for Activation-aware Weight Quantization, now the standard for 4-bit model serving in production.

Following the acquisition, Eigen AI’s optimization layers will integrate directly into Nebius Token Factory, which provides enterprise-grade autoscaling endpoints and fine-tuning pipelines across major open-source models.

“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 integration of Eigen AI’s optimization capabilities and founding team will establish Nebius Token Factory at the frontier of inference.”

The acquisition targets the rapidly growing AI inference market, which is forecast to account for about two-thirds of compute demand this year. Open-source model usage is rising alongside it, making system optimization critical infrastructure.

Nebius shares surged over 11% Friday on the news. The stock has gained 84% year-to-date and nearly sixfold over the past 12 months. The company reports Q1 2026 results on May 13.

The deal follows Nebius’s acquisition of Tavily for $275 million in February and comes as the company experiences explosive growth. Revenue jumped from $11.4 million in Q1 2024 to $227.7 million in Q4 2025. Full year 2026 guidance stands at $3 to $3.4 billion.

The 20-person Eigen AI team will help establish a Nebius engineering presence in the San Francisco Bay Area, accelerating the company’s US expansion. As of December 31, 2025, Nebius reported $3.68 billion in cash and cash equivalents.

Read more: Nebius acquires AI model optimization startup Eigen AI for $643M