ChatGPT is owned by OpenAI, the company behind its development and deployment....

https://wiki-zine.win/index.php/Can_a_Nonprofit_Control_a_Company_with_Less_Than_50%25_Equity%3F_Exploring_the_OpenAI_Foundation_Example

ChatGPT is owned by OpenAI, the company behind its development and deployment. The OpenAI Foundation oversees ChatGPT’s governance to ensure responsible use. While Microsoft is a significant investor and partner, it does not own or control ChatGPT