AI inference company Baseten is close to finalizing a stunning $1.5 billion funding round at a $13 billion valuation, the Wall Street Journal reports. Just five months ago, the startup announced that it had raised a $300 million Series E at a $5 billion valuation. And that round was just nine months after raising a $150 million Series D. If finalized, this latest round would represent a 160% increase in valuation in less than half a year.

However, the WSJ reports that this is a split-priced round, a tactic startups are using to boost their headline valuation and make lead investors look good on paper. Some investors in this latest funding round are reportedly coming in at a $13 billion valuation, while others at $11 billion, sources told the Journal. This deal is said to be co-led by Spark Capital, Sands Capital, Altimeter Capital, and Wellington Management. Launched in 2019, Baseten is a startup benefiting from what The Next Wave hailed the โ€œinference gold rush,โ€ in which VCs are pouring enormous amounts of money into companies building the inference layer.

Inference is what the model does after a user submits a prompt. Baseten promises to handle inference quickly while controlling costs by routing requests to the best-for-task model, especially to competent, less-expensive open source alternatives.