OpenAI is in talks to raise a funding round that would value the artificial intelligence startup at more than $100 billion, CNBC has learned.

Thrive Capital is leading the round and will invest $1 billion, according to a source with knowledge of the matter who asked not to be named because the details are confidential.

Earlier this year, OpenAI was reportedly valued at more than $80 billion, up from $29 billion the prior year. Annualized revenue reportedly surpassed $2 billion earlier this year. Growth took off in late 2022 after the company launched its ChatGPT chatbot and has continued as it rolled out products for businesses and expanded into AI-generated photos and videos.

The Wall Street Journal was first to report on the talks and said that Microsoft, which is OpenAI's biggest backer, is also participating in the round. Microsoft declined to comment.

The news follows OpenAI's announcement last week that it would debut a prototype of its search engine, called SearchGPT, which aims to give users "fast and timely answers with clear and relevant sources."

The company said it eventually plans to integrate the tool, which is currently being tested with a small group of users, into its ChatGPT chatbot.

The rollout could have implications for Google and its dominant search engine. Since the launch of ChatGPT, Alphabet investors have been concerned that OpenAI could take market share from Google in search by giving consumers new ways to seek information online. 

With this prototype, OpenAI is testing the waters for doing just that, promising users the chance to "search in a more natural, intuitive way" and ask follow-up questions "just like you would in a conversation."

"We think there is room to make search much better than it is today," OpenAI CEO Sam Altman wrote Thursday in a post on X.

An OpenAI spokesperson declined to comment.

— CNBC's Jordan Novet contributed to this report.