Hebrew to English Bus/Financial Law: Taxation & Customs

טופס של רשות המסים בישראל.
שם העוסק, ס.ת., ח. מ.א., מס' תיק

תעודת עוסק מורשה

I've been searching everywhere, can't find what is that, there has been an question regarding this http://www.proz.com/kudoz/hebrew_to_english/law_taxation_cus...
but nothing regarding this abbreviation.
According to this link its חברה מושרית but there is also א there, and for some reason space between ח and מ.א., there must be a reason it was made that way