Suppose I want to abbreviate British SEO Market. Which is the right way? BSEOM or BSM?
I advise you to use BSEOM. My reason is:
UN is an acronym/abbreviation of United Nations as you know. If the latter one was the right way, they would abbreviate it as UESCO, not UNESCO*. Same for United States Coast Guard... It is USCG, not UCG.
*UNESCO - United Nations Educational, Scientific, and Cultural Organization