River AI Raises $1.1B for Open-Weight AI Full Stack

River AI, founded by Igor Babuschkin, has raised about $1.1 billion in a seed/Series A round led by General Catalyst and AMP PBC, with strategic investments from NVIDIA, AMD Ventures, Y Combinator, and Temasek. The company aims to reinvent AI by enabling companies to train and own open-weight models and to build a full stack—from training to hardware—that brings personal AI agents close to users. River offers an API for LoRA fine-tuning and reinforcement learning on open-weight models, promising faster on-demand training runs and cost savings versus closed, private models. The founders and investors frame the move toward open, affordable AI as essential for American resilience and leadership in open weights, while some reports note terms and final participation details are still evolving. River’s mission emphasizes user ownership of intelligence and personalized AI that learns from individual data, with plans that extend beyond software to accompanying hardware. Some outlets report a potential company valuation around $5 billion, underscoring brisk appetite for open-weight, user-centric AI tooling in the current funding environment.