| 1 | MRM | Aerocharter, Inc. | Callsign: Maritime, | CDN | AVCODES |
| 2 | MRM | Murmansk Aviation Enterprise, LLC | Callsign: Murman, | RUS | AVCODES |
| 3 | MRM | Aerocharter | | | ICAO1 |
| 4 | MRM | MIDLAND RAILWAY OF MANITOBA | | | PWRC |
| 5 | MRMB | MEDINA REYNA, MARIA GABRIELA | | | SCAC4 |
| 6 | MRMC | MRM SPECIALIZED TRUCKING | | | SCAC4 |
| 7 | MRMD | MARIMED SHIPPING INC | | | SCAC4 |
| 8 | MRMF | MENTOR MEDIA LTD | | | SCAC4 |
| 9 | MRMG | MONROE TOOL AND MANUFACTURING | | | SCAC4 |
| 10 | MRMH | MOTORES MENDEZ | | | SCAC4 |
| 11 | MRMI | MARTINEZ REYNA, MIGUEL | | | SCAC4 |
| 12 | MRMJ | MARTINEZ MARDUENO, JUAN | | | SCAC4 |
| 13 | MRMN | MARME | | | SCAC4 |
| 14 | MRMO | MORALES, MANUEL AND MORALES, ARTURO | | | SCAC4 |
| 15 | MRMQ | MITRANO REMOVAL SERVICE LLC | | | SCAC4 |
| 16 | MRMR | MORGAN RAMIREZ, MIGUEL GUILLERMO | | | SCAC4 |
| 17 | MRMS | MURPHY MOVING & STORAGE INC | | | SCAC4 |
| 18 | MRMT | MRM TRUCKING | | | SCAC4 |
| 19 | MRMU | GCATAINER BV | | | SCAC4 |
| 20 | MRMV | MIDDLE RIVER MARINE SERVICE | | | SCAC4 |
| 21 | MRMX | Midwest Railcar Corp. | added 4/2007 | | NAKINA |
| 22 | MRMX | MRMX Leasing & Management, LLC | 7/2005 (not listed) | | NAKINA |
| 23 | MRMX | MIDWEST RAILCAR CORP. [MRMX LEASING & MANAGEMENT, LLC] | | | PWRC |
| 24 | MRMX | MRMX Leasing and Management | | | RSRV |
| 25 | MRMX | MIDWEST RAILCAR CORPORATION | | | SCAC4 |
| 26 | MRMY | MR M LLC | | | SCAC4 |
| 27 | MRMZ | MONTICELLO RAILWAY MUSEUM | | | PWRC |
| 28 | MRMZ | Monticello Railway Museum | | | RSRV |
