Which company owns OpenAI?

Could you please clarify for me who exactly is the owner of OpenAI? I understand that it's a renowned artificial intelligence research and development company, but I'm not entirely sure about its ownership structure. Is it a publicly traded company, or is it privately held? Are there any major investors or stakeholders that I should be aware of? I'm particularly interested in understanding the financial backing behind OpenAI and how it affects their operations and research goals. Thank you for your assistance in clarifying this matter.