ChatGPT is owned by OpenAI, the company that developed and maintains the AI....

https://bizzmarkblog.com/why-microsoft-investment-value-is-not-the-same-as-governance-control/

ChatGPT is owned by OpenAI, the company that developed and maintains the AI. The OpenAI Foundation oversees the governance to ensure responsible use. While Microsoft is a significant investor and partner, it does not own ChatGPT or control OpenAI