AI startup Anthropic on Monday announced it raised $3.5 billion at a $61.5 billion post-money valuation, led by Lightspeed Venture Partners.

The Series E, which also had participation from Bessemer Venture Partners, Cisco Investments, D1 Capital Partners, Fidelity Management & Research Company, General Catalyst, Jane Street, Menlo Ventures, and Salesforce Ventures, brings the company’s total raised to $18.2 billion, according to Crunchbase.

“With this investment, Anthropic will advance its development of next-generation AI systems, expand its compute capacity, deepen its research in mechanistic interpretability and alignment, and accelerate its international expansion,” the company wrote in a blog post. “Anthropic is focused on developing AI systems that can serve as true collaborators, working alongside teams to tackle complex projects, synthesize information across fields, and help organizations achieve outsized impact.”

Anthropic’s mammoth round of fundraising comes shortly after the launch of the company’s latest flagship AI model, Claude 3.7 Sonnet, a “hybrid reasoning” model that can more carefully consider queries before answering. The model is a part of Anthropic’s broader effort to simplify the user experience around its AI products. Most AI chatbots today have a daunting model picker that forces users to choose from several different options that vary in cost and capability. Labs like Anthropic would rather you not have to think about it — ideally, one model does all the work.

Anthropic’s business is growing. The company’s annual revenue run rate was reportedly around $1 billion last year. That number has increased by 30% so far in 2025 as the company rakes in cash from the API that serves its models and sells more subscriptions to its AI chatbot, Claude. But Anthropic is spending an enormous amount developing its AI systems. The company told investors that it expects to burn $3 billion this year, per The Information.

In a bid to bolster profitability, Anthropic has shifted some of its focus to releasing new tools and subscription tiers, such as computer-using “agents,” a desktop client, and mobile applications. The company also opened offices in Europe and made several high-profile hires, including Instagram co-founder Mike Krieger, OpenAI co-founder Durk Kingma, and ex-OpenAI safety researcher Jan Leike.

Anthropic has strengthened its relationship with Amazon, as well, which has become a major investor in — and collaborator with — the AI startup. Amazon poured an additional $4 billion into Anthropic in November, and said it would work with Anthropic to optimize its custom AI chips, Trainium, for model training workloads. Amazon also teamed up with Anthropic to build its upgraded Alexa virtual assistant experience, Alexa+. Anthropic’s models power portions of Alexa+.

Anthropic was co-launched in 2021 by CEO Dario Amodei, who was once VP of research at OpenAI and reportedly split with the firm after disagreements over OpenAI’s roadmap. Amodei brought along a number of ex-OpenAI employees to start Anthropic, including OpenAI’s former policy lead, Jack Clark.

Anthropic often attempts to position itself as more safety-focused than OpenAI.