Calculated Data from Company Custom Form to Issue Custom Form

I have been able to successfully use calculated data from a Company Custom Form to a Task and/or Project Custom Form, but I'm struggling to get it to work on an Issue Custom Form. Any ideas? I have the following fields in a Company custom form, I would like it to populate into the Issue form based on the company chosen: Business group & Business type. Open to suggestions. The field in the Issue custom form where the Company name is captured is {Client}; I tried {Company}. {Business Group} and {Client}.{Business Group}