The startup widely known as “ChatGPT for doctors” has raised a new round of funding that values the company at $12 billion.
Miami, Florida-based OpenEvidence has closed on $250 million in funding led by Thrive Capital and DST, the company told CNBC. The startup raised its first external capital in February, raising $75 million from Sequoia at a $1 billion valuation, but the valuation jumped to $6 billion in October.
In less than a year, OpenEvidence has raised $700 million from investors including: Google venture arm, NvidiaKleiner Perkins, David Sachs’ Craft Ventures, and Mayo Clinic.
The company was founded in 2022 by Daniel Nadler, who previously founded Kensho Technologies, an artificial intelligence company that was acquired by Standard & Poor’s in 2018 for about $700 million, and Zachary Ziegler, who holds a PhD in artificial intelligence from Harvard University. Nadler’s latest venture provides a chatbot for doctors, and its AI models are trained on data and information from top scientific journals, Nadler said in an interview.
“‘ChatGPT for Physicians’ is a useful abbreviation, but what we’re really doing is helping physicians make high-stakes clinical decisions at the point of care,” Nadler said. “They are not trained on the open internet and social media, where poor quality medical information can flow.”
Nadler claimed that OpenEvidence is the most widely used AI platform by physicians in the United States, with more than 40% of physicians utilizing the tool. He pointed to the big opportunity in health care, which accounts for $5 trillion in annual spending and nearly 20% of the U.S. gross domestic product.
“Health care is the largest sector of the real economy,” Nadler said. “People are realizing there can be a lot of winners in this space.”
These names may include OpenAI and Anthropic.
OpenAI launched ChatGPT Health earlier this month, and Anthropic launched Claude Healthcare. Both are Health Insurance Portability and Accountability Act (HIPAA) compliant extensions of popular consumer chatbots.
While competition is increasing, Nadler said his company’s moat is focused on physicians, quality of data and first-mover advantage.
“We already collect hundreds of millions of actual clinical consultations from board-certified physicians, and that feedback loop is incredibly difficult to replicate,” Nadler said. “Even if someone copied this playbook today, they would still be far behind because it’s not just partnerships, it’s actual usage data.”
rely on advertising
The company’s annual revenue last year exceeded $100 million, driven primarily by organic growth, according to OpenEvidence. Nadler said 95% of new users heard about OpenEvidence from another doctor.
“Most of America’s health care is not done in multibillion-dollar hospitals in New York or San Francisco,” Nadler said. “It’s happening in small businesses that don’t have an IT department or a budget for expensive software.”
OpenEvidence was one of the first AI startups to rely on advertising for revenue, which Nadler said allows for faster deployment and broader adoption compared to paid subscription models. Businesses can pay promotional fees through video ads on the OpenEvidence app.
The artificial intelligence industry is starting to move toward advertising-based revenue. OpenAI announced last week that it is testing an ad-supported version of ChatGPT. Nadler said he is trying to be more disciplined than some companies that are “openly planning to burn billions or even tens of billions of dollars over the next few years.”
“This is a big bet, a very risky bet,” Nadler said, adding that Open Evidence is trying to balance growth with ultimate profitability. “We’re not running this like a private equity portfolio company, but we’re also not planning on spending billions of dollars over the next year.”
AI startups are picking up steam this year after a slump in 2025.
According to CB Insights, there were six AI funding rounds of more than $1 billion in the third quarter of last year. Anthropic was in talks to raise an additional $10 billion in January, and Elon Musk’s xAI announced $20 billion in funding this month.
Nadler said he feels pressure as major technology companies are aggressively pursuing acquisitions in the space, but remains committed to building OpenEvidence as an independent company.
“I’ve done the acquisition route before,” he said. “That could be great, but this time we want to create something that will grow over the years.”
As for initial public offerings (IPOs), he said SpaceX, OpenAI and Anthropic, which are rumored to be potential candidates in 2026, need to go public first.
“There is order in nature,” Nadler said. “The underlying model companies go public first. Then the application layer follows. This is how the Internet is unfolding, and this cycle will unfold as well.”
Correction: A previous version of this article incorrectly identified the company’s location.
View: OpenAI Investor Letter
