The Royal Manticoran Merchant Marine, or RMMM, comprised most Manticoran merchant ships that transported cargo and people during times of both peace and war. It was the 4th largest merchant marine in the galaxy.
Freighters travelling under Manticoran flag, like those of Hauptman Lines, were generally part of the RMMM, carrying the prefix RMMS (Royal Merchant Marine Ship). The RMMM's officer were trained at the Merchant Fleet Academy. (HH6, HHA4.2: WOS)