River AI, the two-month-old startup from xAI co-founder Igor Babuschkin, raised $1.1B across seed and Series A, one of the largest rounds for any company founded this year.

The round was led by General Catalyst and AMP, with strategic checks from Nvidia and AMD plus Y Combinator and Temasek. River is building personalized AI that users and organizations own and control, and says its API runs reinforcement-learning training two to four times cheaper than closed rivals.

With no valuation disclosed, the raise is a bet that open, user-owned models can challenge the closed-source AI giants.