If I were to have a forex account while residing in Thailand and it was making some money, would I be required to also have a work permit?

Note: I am on a non-o visa extension based on thai spouse. And if the answer is yes to the permit how do I proceed with the application process based on some of the rules for a work permit are concerning an employer, which I don't have.

Please any help with this will be deeply appreciated.

I am sure there are many here with such accounts. How would Thai immigration know?

No you don't need one.

It would serve no purpose anyway as you're not working.