None of the major LLM chat providers (ChatGPT, Claude and Gemini, and I just confirmed this) claim rights over your input.
They also don't claim rights over your output, but because of how copyright law might apply, they explicitly assign all the rights to the generated output.
Not just that but, even if they wanted to claim ownership of the output, courts in the US have deemed that copyright cannot be assigned to machine-generated output.
So yeah, happy to take a look at a counter-example if you have one (aside from GLM 5.3, obv.).
> To the extent the User Content includes a person’s image, likeness, voice, or other similar attributes, you grant SpaceXAI the same rights to use those attributes as part of the User Content as described above. You represent and warrant that you have obtained all rights, licenses, notices, permissions, and consents necessary for SpaceXAI to use that User Content.
https://x.ai/legal/terms-of-service
These are arguably even worse to be honest. Absolute nightmare.
However, if we check the market share of generative AI providers, ChatGPT+Claude+Gemini make up around 88%; while Grok is 2-4% depending on who you ask.