Baseten does not make AI models. It runs them. The company's software optimizes inference for open-source models, handling the latency, GPU scheduling, and cost-per-token arithmetic that determines whether an AI application is profitable or a money pit. On June 18, it closed a $1.5 billion funding round at a $13 billion valuation. Five months ago, Baseten was worth $5 billion. Its annualized revenue grew from $200 million to $600 million between December 2025 and March 2026, a reported 1,900% year-over-year increase. Altimeter Capital, Conviction, Spark Capital, Sands Capital, and Wellington Management co-led.
That trajectory makes a specific argument about where value is concentrating in the AI stack. The model builders are large and visible. The inference layer is quieter, apparently faster-growing, and now worth more per dollar of revenue than almost any model company not named OpenAI or Anthropic. Baseten's customers (Cursor, Mercor, OpenEvidence) report 30% cost savings versus closed-source APIs. When you cut 30% from the input that determines your unit economics, that vendor becomes load-bearing infrastructure.
