Baseten, an AI inference startup, is raising $1.5 billion（約2400億円） at a $13 billion（約2.1兆円） valuation—a 160% jump in five months—though the round uses split pricing that may inflate the headline figure.

What happened: Baseten is close to finalizing a $1.5 billion（約2400億円） funding round at a $13 billion（約2.1兆円） valuation, according to the Wall Street Journal. The round is co-led by Spark Capital, Sands Capital, Altimeter Capital, and Wellington Management. This comes just five months after the startup raised a $300 million（約480億円） Series E at a $5 billion（約8000億円） valuation.

Why it matters: Baseten benefits from what has been called the 'inference gold rush,' in which venture investors are pouring money into companies building the inference layer—the processing step where an AI produces an answer after a user submits a prompt. Baseten's model is to route requests to the most cost-effective model for each task, including open source alternatives, to handle inference quickly while keeping costs down.

What to watch: The WSJ reports this is a split-priced round, a tactic where some investors come in at the $13 billion（約2.1兆円） valuation while others at $11 billion（約1.8兆円）. This structure is being used by startups to boost headline valuations. The deal's finalization is still pending.