The artificial intelligence start-up Anthropic said on Monday that it had completed a new fund-raising deal that valued the company at $61.5 billion, up from about $16 billion a little more than a year ago.
Led by the venture capital firm Lightspeed Venture Partners, the new round will pump an additional $3.5 billion into the company. Since its founding in 2021, Anthropic has raised more than $14.8 billion from venture firms like Menlo Ventures and tech giants like Amazon, Google and Salesforce.
The deal comes amid a surge in funding activity for the industry’s most prominent A.I. start-ups. OpenAI is set to complete a $40 billion fund-raising deal that would value the company at $300 billion, nearly double its valuation from just five months ago. Elon Musk’s xAI is in talks for a new financing round that could value it at as much as $75 billion, up from about $40 billion just two months ago, two people with knowledge of the discussions said.
OpenAI started the A.I. boom in late 2022 with the release of ChatGPT, setting off a funding surge that moved billions into a wide range of start-ups. Enthusiasm among investors for A.I. companies cooled in 2024, as several high-profile start-ups were essentially folded into tech giants like Google and Amazon. But as companies like OpenAI and Anthropic, with its chatbot called Claude, have continued to improve their A.I. technologies, investor interest has returned.
(The New York Times has sued OpenAI and its partner, Microsoft, accusing them of copyright infringement of news content related to A.I. systems. OpenAI and Microsoft have denied those claims.)
Dario Amodei, Anthropic’s chief executive, and his sister, Daniela Amodei, its president, founded the company as a start-up that would build A.I. with guardrails. Like several others on the company’s founding team, they had left OpenAI after disagreements with the start-up’s leadership over how its technologies were being funded and released through Microsoft.
In a podcast interview in 2023, Mr. Amodei said there was a 10 to 25 percent chance that A.I. technology could destroy humanity. But in October, he struck a more optimistic tone, publishing a 14,000-word essay on the potential benefits of A.I. technologies.
“I think that most people are underestimating just how radical the upside of A.I. could be, just as I think most people are underestimating how bad the risks could be,” he wrote.
The next month, Anthropic raised $4 billion from Amazon, its largest investor, which has put a total of $8 billion into the start-up. Anthropic builds and operates its A.I. systems using computer data centers owned by Amazon and Google.
