River AI raises $1.1 billion to build personally owned AI agents

River AI, the startup founded by xAI co-founder Igor Babuschkin, announced $1.1 billion in combined Series Seed and Series A funding on August 11, 2026, roughly two months after emerging from stealth in June.

General Catalyst and AMP PBC led the round, River AI said, with participation from chipmakers Nvidia and AMD Ventures, plus Y Combinator and Singapore’s Temasek. The raise is unusually large for a company this young, a mark of how aggressively investors are funding credentialed founders leaving frontier labs.

Babuschkin, who previously worked at DeepMind and OpenAI before co-founding xAI, said River aims to rebuild the AI stack end to end — training, models, product layer and hardware — around personally owned AI agents rather than centralized, rented intelligence.

The first product is an application programming interface that River says lets enterprises run reinforcement-learning fine-tuning jobs on open-weight models in 15 to 20 minutes without dedicated infrastructure, at two to four times the cost savings of closed-source alternatives, and with support for low-rank adaptation, or LoRA, fine-tuning. General Catalyst Chief Executive Hemant Taneja framed the investment as a bet on open-weight AI leadership.

The performance and cost claims come from River and have not been independently verified, and the company is two months old with no public track record at scale. Whether “personally owned” agents become a real market or stay a positioning line against the API incumbents is the open question the funding does not answer.