Baseten Secures $1.5B Funding, Valuation Hits $13B

Baseten, the AI inference infrastructure startup, is closing a $1.5 billion funding round that would value the company at up to $13 billion. That is a staggering jump from its $5 billion valuation just six months ago.

The round is co-led by Altimeter Capital, Conviction, Spark Capital, Sands Capital, and Wellington Management. It is structured in two tiers, with proposed valuations at $11 billion and $13 billion, giving later participants a higher entry price for the privilege of getting in at all.

Baseten’s annualized revenue run-rate has surged from roughly $200 million to $600 million. Baseten builds software and multi-cloud compute infrastructure that helps companies optimize and customize open-source AI models, handling the inference workloads — the computationally expensive process of actually getting a trained model to produce useful outputs.

The company counts Cursor, Mercor, and OpenEvidence among its key customers. At least one Baseten customer has reported achieving up to 30% reduction in costs compared to closed-source alternatives.

Baseten’s 2026 fundraising cadence has been relentless. The company closed a $300 million Series E in January at a $5 billion valuation. By May, discussions were already underway to raise nearly $1 billion at an $11 billion pre-money valuation. Now, the round has ballooned to $1.5 billion at up to $13 billion.

Before this latest round, cumulative funding for Baseten approached or exceeded $585 million. That figure includes a $150 million Series D completed in September 2025 at approximately $2.15 billion, meaning the company has roughly sextupled its valuation in under a year.

Baseten’s pitch is straightforward: open-source models are getting good enough that many enterprises don’t need to pay the premium for proprietary ones. But deploying open-source models efficiently requires specialized infrastructure for model serving and latency optimization. That’s the gap Baseten fills.

Baseten operates squarely in traditional AI infrastructure with no ties to cryptocurrency or blockchain. At $600 million in annualized revenue, the company is trading at roughly 22 times revenue at the high end of the valuation range.