AI Inference Startup Baseten Reportedly Raising $1.5B Months After Last Mega Round

AI inference company Baseten is reportedly close to finalizing a stunning $1.5 billion funding round at a $13 billion valuation, according to the Wall Street Journal. This comes just five months after the startup announced a $300 million Series E at a $5 billion valuation—and only nine months after raising a $150 million Series D. If completed, this latest round would represent a 160% increase in valuation in less than half a year. However, the WSJ notes that this is a split-priced round, a tactic increasingly used by AI startups in 2026 to inflate headline valuations and make lead investors look stronger on paper. In this case, some investors are reportedly coming in at a $13 billion valuation, while others are entering at $11 billion. The deal is said to be co-led by Spark Capital, Sands Capital, Altimeter Capital, and Wellington Management. Founded in 2019, Baseten is riding what analysts have dubbed the “inference gold rush,” with venture capitalists pouring massive sums into companies building the inference layer—the process that happens when a model responds to a user prompt. Baseten promises fast, cost-controlled inference by routing requests to the best model for each task, particularly favoring competent, less expensive open-source alternatives.

via TechCrunch AI