Oct 2 (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 ( MSFT ), and new

participation from Nvidia ( NVDA ).