Venture capital firm Lightspeed Venture Partners is leading the funding round, according to the sources, who requested anonymity to discuss private matters.

The new funding, $6 billion in total, will mark a jump in valuation for Anthropic, a major competitor of OpenAI in the foundation model space. Anthropic was valued at around $18 billion in a fundraise led by Menlo Ventures last year.

Anthropic declined to comment. The Wall Street Journal first reported the funding on Tuesday.

Amazon late last year doubled its investment in the startup to $8 billion, as the e-commerce giant went up against Big Tech rivals in a race to capitalize on generative AI technology. The latest $4 billion issued to Amazon in convertible notes will be converted into equity through this round.

Anthropic, whose annualized revenue hit about $875 million, sells access to its models directly and through third-party cloud services including Amazon Web Services. The large language models development requires expensive computing, as well as top talents.

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Co-founded by former OpenAI executives and siblings Dario and Daniela Amodei, San Francisco-based Anthropic also received $2 billion investment from Alphabet in 2023. Microsoft-backed OpenAI triggered an AI arms race after it launched ChatGPT in November 2022. The growing popularity of the company and new product launches helped it close a $6.6 billion funding round in October, potentially taking its valuation to $157 billion.

With outsized funding rounds by companies such as Anthropic and xAI, AI startups have accounted for nearly half of the venture capital dollar raised in the U.S. last year, according to PitchBook data.

Venture capital firm Lightspeed Venture Partners is leading the funding round, according to the sources, who requested anonymity to discuss private matters.

The new funding, $6 billion in total, will mark a jump in valuation for Anthropic, a major competitor of OpenAI in the foundation model space. Anthropic was valued at around $18 billion in a fundraise led by Menlo Ventures last year.

Anthropic declined to comment. The Wall Street Journal first reported the funding on Tuesday.

Amazon late last year doubled its investment in the startup to $8 billion, as the e-commerce giant went up against Big Tech rivals in a race to capitalize on generative AI technology. The latest $4 billion issued to Amazon in convertible notes will be converted into equity through this round.

Anthropic, whose annualized revenue hit about $875 million, sells access to its models directly and through third-party cloud services including Amazon Web Services. The large language models development requires expensive computing, as well as top talents.

Discover the stories of your interest

Co-founded by former OpenAI executives and siblings Dario and Daniela Amodei, San Francisco-based Anthropic also received $2 billion investment from Alphabet in 2023. Microsoft-backed OpenAI triggered an AI arms race after it launched ChatGPT in November 2022. The growing popularity of the company and new product launches helped it close a $6.6 billion funding round in October, potentially taking its valuation to $157 billion.

With outsized funding rounds by companies such as Anthropic and xAI, AI startups have accounted for nearly half of the venture capital dollar raised in the U.S. last year, according to PitchBook data.