Do you have a title? If nothing else, you must make up something to put on your tax forms each year. (Uhm. "firstname.lastname@example.org" doesn't quite work does it.)
President? Proprietor? Manager? Director? Chief?
You said multinationals. So make sure you use something that conveys "the head honcho" in all dialects of English.*
* In real life, I have an ineradicable mental block on the name of our supreme high librarian. So I refer to him that way, and the librarians know who I mean.