Microsoft Corp is in talks to invest $10 billion into OpenAI, the owner of ChatGPT, which will value the San Francisco-based firm at $29bn, Semafor reported on Monday, citing people familiar with the matter.

The funding includes other venture firms and deal documents were sent to prospective investors in recent weeks, with the aim to close the round by the end of 2022, the report said.

Microsoft declined to comment, while OpenAI did not immediately respond to Reuters’ request for comment.

This follows a Wall Street Journal report that said OpenAI was in talks to sell existing shares at a roughly $29bn valuation, with venture capital firms such as Thrive Capital and Founders Fund buying shares from existing shareholders.

OpenAI, founded by Tesla Inc CEO Elon Musk and investor Sam Altman, made the ChatGPT chatbot available for free public testing on Nov 30. A chatbot is a software application designed to mimic human-like conversation based on user prompts.

The Semafor report said the funding terms included Microsoft getting 75 per cent of OpenAI’s profits until it recoups its initial investment once OpenAI figures out how to make money on ChatGPT and other products like image creation tool Dall-E.

On hitting that threshold, Microsoft would have a 49pc stake in OpenAI, with other investors taking another 49pc and OpenAI’s nonprofit parent getting 2pc, the report said, without clarifying what the stakes would be until Microsoft got its money back.

Microsoft, which invested $1bn in OpenAI in 2019, was working to launch a version of its search engine Bing using the AI behind ChatGPT, the Information reported last week.