OpenEvidence, the ‘ChatGPT for Doctors’ AI startup, hits $12B valuation in $250M Thrive-led round

OpenEvidence just pulled off one of the fastest valuation climbs in healthcare AI. The Miami-based startup, often described as “ChatGPT for doctors,” closed a $250 million funding round led by Thrive Capital and DST, valuing it at $12 billion, the company said Wednesday. That jump lands less than a year after the company first raised outside capital, when Sequoia wrote a $75 million check in February at a $1 billion valuation. By October, that figure had already surged to $6 billion.

In under twelve months, OpenEvidence has now raised roughly $700 million from a heavyweight roster of backers that includes Google’s venture arm, Nvidia, Kleiner Perkins, David Sacks’ Craft Ventures, and the Mayo Clinic. The pace has turned heads even in a market where mega-rounds have become more common.

“OpenEvidence, based in Miami, Florida, closed a $250 million financing, led by Thrive Capital and DST, the company told CNBC. The startup first raised outside capital in February, when it reeled in $75 million from Sequoia at a $1 billion valuation, before its value jumped to $6 billion in October,” CNBC reported.

Inside OpenEvidence’s Bet on Doctors Over Consumers

The company was founded in 2022 by Daniel Nadler, who previously built Kensho Technologies before selling it to Standard & Poor’s for about $700 million in 2018, and Zachary Ziegler, a Harvard PhD student focused on artificial intelligence. Nadler’s latest venture offers a chatbot built specifically for physicians, trained on peer-reviewed research and medical journals.

“‘ChatGPT for doctors’ is a useful shorthand, but what we really do is help physicians make high-stakes clinical decisions at the point of care,” Nadler said. “It’s not trained on the open internet or social media, which can introduce low-quality medical information.”

Nadler claims OpenEvidence has become the most widely used AI platform among U.S. physicians, with more than 40% of doctors now relying on it. He points to healthcare’s massive footprint, nearly 20% of U.S. GDP and about $5 trillion in annual spending, as proof of how large the opportunity is.

“Health care is the largest segment of the real economy,” Nadler said. “People realize there could be a lot of winners in the space.”

Those potential winners already include OpenAI and Anthropic. OpenAI rolled out “ChatGPT Health” earlier this month, while Anthropic introduced “Claude Healthcare.” Both products offer HIPAA-compliant versions of their consumer chatbots, aimed squarely at hospitals and clinics.

Competition is heating up, yet Nadler believes OpenEvidence holds an edge.

“We’ve already gathered hundreds of millions of real-world clinical consultations from verified physicians — that feedback loop is incredibly hard to replicate,” he said. “Even if someone copied the playbook today, they’d still be far behind because it’s not just the partnerships, it’s the real-world usage data.”

OpenEvidence crossed $100 million in annualized revenue last year, driven largely by word-of-mouth growth. Nadler says 95% of new users hear about the product from another physician.

“Most health care in America isn’t happening at billion-dollar hospitals in New York or San Francisco,” he said. “It’s happening in small practices that don’t have IT departments or budgets for expensive software.”

The startup took an unconventional route to monetization, relying on advertising rather than subscriptions. Companies can promote products through video ads inside the OpenEvidence app, a model Nadler says speeds adoption and keeps the tool accessible to doctors.

That approach is starting to gain traction across AI more broadly. Last week, OpenAI said it was testing an ad-supported version of ChatGPT. Nadler says he’s trying to avoid the cash-burn mindset sweeping parts of the industry.

“That’s a big bet, and a very risky bet,” he said, referring to rivals openly planning to burn tens of billions. “We’re not running this like a private equity portfolio company, but we’re also not planning on burning billions of dollars over the next year.”

AI fundraising shows no sign of slowing. CB Insights reports six AI rounds above $1 billion in the third quarter of last year alone. Anthropic is now in talks to raise another $10 billion, and Elon Musk’s xAI just announced a $20 billion round.

Nadler admits he feels pressure as Big Tech circles the sector for acquisitions, yet he’s staying focused on building OpenEvidence as a standalone business.

“I’ve done the acquisition route before,” he said. “It can be great. But this time, I want to build something that compounds over many years.”

An IPO is on the radar, just not yet. Nadler expects foundation model companies like OpenAI and Anthropic to test public markets first.

“There’s an order to nature,” he said. “Foundation model companies go public first. Then the application layer follows. That’s how the internet played out, and that’s how this cycle will play out, too.”

TechStartups first covered OpenEvidence in February 2025 when the company raised $75 million in a Sequoia-led round that pushed it into unicorn territory. Back then, the startup was already gaining traction among doctors nationwide.

Since its inception five years ago, OpenEvidence has focused on organizing medical knowledge and making it usable at the point of care. The platform now serves hundreds of thousands of verified physicians across more than 10,000 healthcare centers in the U.S. Unlike consumer AI tools, its models are trained on specialized medical content, including exclusive partnerships with publishers like the New England Journal of Medicine. The service remains free for verified U.S. doctors.

Nadler initially self-funded the company after selling Kensho, followed by a small friends-and-family round in 2023. This latest financing marks its first major institutional backing, pushing total funding well past $100 million.

From a scrappy bootstrapped project to a $12 billion company in under four years, OpenEvidence’s rise signals just how fast healthcare AI is moving. And as competition intensifies, Nadler seems determined to keep building rather than sell out early.