Anthropic, a San Francisco-based AI startup and rival to OpenAI, has raised $450 million in Series C funding led by Spark Capital, a venture capital firm that has backed companies like Twitter, Slack and Coinbase. The round also included investments from Google, Salesforce Ventures, Sound Ventures, Zoom Ventures and others.

Founded by siblings Dario and Daniela Amodei, former employees of OpenAI, in 2021, the new $450 million raise comes three months after Anthropic received $300 million from Google and gives the startup about $1.45 billion in total funding, second only to OpenAI, which has raised a total of over $11.3 billion to date. It takes the company’s valuation to $4 billion, according to PitchBook.

“We are thrilled that these leading investors and technology companies are supporting Anthropic’s mission: AI research and products that put safety at the frontier,” CEO Dario Amodei said.

Claude, the company’s flagship product, is based on Anthropic’s research into training helpful, honest and harmless AI systems. The company says Claude is designed to provide reliable AI services that can positively impact businesses and consumers now and in the future.

Yasmin Razavi, a general partner at Spark Capital who focuses on growth-stage software investments, has joined Anthropic’s board of directors

As investors actively look for new methods to capitalize on the generative AI trend, rival Inflection AI, a firm developing an AI-powered personal assistant, has garnered $225 million, while another Anthropic rival, Adept, has raised about $415 million.