Who owns ChatGPT output? Can I copyright it or use it commercially?

I publish illustrative scenarios prepared by my practice. All participants and conversations are fictional. The fictional posts are not posts by real users, accounts of client experiences, or reports of actual results.
Illustrative scenario prepared by my practice.
For informational purposes only. AI copyright law is rapidly evolving.
Hypothetical question

I've been using ChatGPT to help write blog posts and marketing copy for my business. Now I'm wondering about the legal side of things.

If ChatGPT writes something for me, who actually owns it? Can I claim copyright? Can I sell it? What does the OpenAI terms of service actually say about this?

Getting conflicting info online and want to understand the real situation.