River AI, founded by xAI co-founder Igor Babuschkin, secured $1.1 billion in a combined seed/Series A led by General Catalyst and AMP PBC, with Nvidia, AMD Ventures, Y Combinator, and Temasek participating.
River came out of stealth in June 2026. Babuschkin (DeepMind, OpenAI, xAI) intends to reinvent AI training so agents become personally trainable assistants rather than worker replacements. Current product: API for LoRA fine-tuning and RL on open-weight models, claiming 15–20 minute complex RL runs and 2–4x cost savings vs closed-source alternatives — company-stated, unverified independently.