Chip giant Nvidia and Microsoft announced on Tuesday investments totalling US$15 billion in AI startup Anthropic, creator of the Claude chatbot, as the AI investment frenzy continues amid emerging fears of a bubble on Wall Street.

Nvidia committed up to US$10 billion while Microsoft – which owns 27 percent of Anthropic rival OpenAI – pledged up to US$5 billion to the maker of Claude AI models.

The deal was part of a sweeping agreement that saw Anthropic commit to purchasing US$30 billion in Microsoft's cloud computing capacity and adopt the latest versions of Nvidia's chip technology.

"We're increasingly going to be customers of each other," said Microsoft CEO Satya Nadella in an online video announcing the deal.

"We will use Anthropic models. They will use our infrastructure, and we'll go to market together to help our customers realise the value of AI."

The investments mark a significant realignment in the generative AI sector, where competition has intensified between ChatGPT-maker OpenAI and rivals including Anthropic, but also Google, which released its latest Gemini model on Tuesday.

California-based Anthropic was launched in 2021 by former OpenAI staff and positions itself as prioritising safety in AI development. Its flagship product is the Claude chatbot and family of models.

With increasing talk among Wall Street analysts of an AI bubble, shares in Nvidia, the world's biggest company by market capitalisation, were down as much as three percent amid a broad sell-off in the tech sectors.

Microsoft's shares were down nearly 3.5 percent.

Sources told CNBC that the fresh investment valued Anthropic at US$350 billion, making it one of the world's most valuable companies. OpenAI was most recently valued at US$500 billion. (AFP)