By Krystal Hu

(Reuters) - OpenAI has raised $6.6 billion from investors at a post-money valuation of $157 billion, cementing the ChatGPT maker's status as one of the most valuable private companies in the world,sources familiar with the matter said on Wednesday. The funding has attracted returning venture capital investors including Thrive Capital and Khosla Ventures, as well as OpenAI's biggest corporate backer Microsoft, and new participation from Nvidia.

(Reporting by Krystal Hu in New York; Editing by Lisa Shumaker)