| 6401 | MONL | MONTGOMERY, N L INC | | | SCAC4 |
| 6402 | MONM | MONTGOMERY TRANSPORTATION BROKERS I | | | SCAC4 |
| 6403 | MONM | Monmouth Bus Lines | | US-NJ | TRAFFIC |
| 6404 | MONO | MONTUORI OIL DELIVERY INC | | | SCAC4 |
| 6405 | MONP | MONLLOR TRANSPORT CORP | | | SCAC4 |
| 6406 | MONQ | MONARCH SHIPPING CO LTD | | | SCAC4 |
| 6407 | MONR | MONTANA CENTRAL RAILROAD | | | PWRC |
| 6408 | MONS | MONTEGA TRANSFER | | | SCAC4 |
| 6409 | MONSA | MONDI ŚWIECIE S.A. | | PL | VKM |
| 6410 | MONSEY | Monsey Tours | | USA | TRAFFIC |
| 6411 | MONT | MOTION TRANSPORT | | | SCAC4 |
| 6412 | MONT | Montour Railroad Company | Real: MTR | USA | TRAFFIC |
| 6413 | MONTI | Monti GmbH | | DE | VKM |
| 6414 | MONU | BAYER CROPSCIENCE LP | | USA | BIC |
| 6415 | MONU | Monsanto | | | RSRV |
| 6416 | MONU | MONSANTO CO | | | SCAC4 |
| 6417 | MONW | MITSUI O.S.K. LINES, LTD. | | | PWRC |
| 6418 | MONW | MONSTER ENTERTAINMENT INC | | | SCAC4 |
| 6419 | MONX | Solutia Inc. | added 1/1998; 7/2000-7/2005; eliminated 7/2009 | | NAKINA |
| 6420 | MONX | Monsanto Co. | added 7/1964; 7/1965-1/1994; eliminated 1/1998 | | NAKINA |
| 6421 | MONX | Monsanto Chemical Co. | 7/1935-4/1961; eliminated 7/1964 | | NAKINA |
| 6422 | MONX | Monsanto Chemical Works | 8/1920-7/1932 | | NAKINA |
| 6423 | MONX | Monsanto Co. | 4/38-1/52 | | NRHS |
| 6424 | MONX | Monsanto Chemical Co. | 10/57-4/61; eliminated 7/64 | | NRHS |
| 6425 | MONX | Monsanto Co. | added 7/64; 7/65-1/94; eliminated 1/98 | | NRHS |
| 6426 | MONX | Solutia Inc. | added 1/98; 7/2000 | | NRHS |
| 6427 | MONX | SOLUTIA INCORPORATED [MONSANTO COMPANY] | | | PWRC |
| 6428 | MONX | Monsanto | | | RSRV |
| 6429 | MONX | SOLUTIA INC | | | SCAC4 |
| 6430 | MONY | MONTGOMERY COUNTY | | | PWRC |
| 6431 | MOO | Moonair | | IL | AVCODES |
| 6432 | MOO | MOORE'S BUS SERVICE INC. | | | PWRC |
| 6433 | MOOA | MOORE, A L & W | | | SCAC4 |
| 6434 | MOOC | MOORE DEPENDABLE TRUCKING | | | SCAC4 |
| 6435 | MOOD | MOOD TRANSPORT LIMITED | | | SCAC4 |
| 6436 | MOOG | MOORE, RON TRUCKING | | | SCAC4 |
| 6437 | MOOH | MORRCO | | | SCAC4 |
| 6438 | MOOK | MOORE, DEREK | | | SCAC4 |
| 6439 | MOOM | MOORMAN FARMS INC | | | SCAC4 |
| 6440 | MOON | MOON, KIM | | | SCAC4 |
| 6441 | MOOO | MOORE BROTHERS INC | | | SCAC4 |
| 6442 | MOOQ | MOORE TRUCK LINES, Truck Investment Co | | | SCAC1 |
| 6443 | MOOU | OEG OFFSHORE GROUP LIMITED | | SGP | BIC |
| 6444 | MOOV | MOORE TRUCKING INC | | | SCAC4 |
| 6445 | MOOZ | MINNESOTA OIL OPERATION | | | PWRC |
| 6446 | MOP | Aeropublicitaria De Angola | | | ICAO1 |
| 6447 | MOP | MITSUI O.S.K. LINES, LTD. | | | PWRC |
| 6448 | MOP | | | USA | TRAFFIC |
| 6449 | MOPB | MORGAN BUILDING TRANSPORT CORP | | | SCAC4 |
| 6450 | MOPI | MISCO ENTERPRISES INC | | | SCAC4 |
| 6451 | MOPL | MOORES PRODUCE LTD | | | SCAC4 |
| 6452 | MOPT | MATA ORTIZ POTS | | | SCAC4 |
| 6453 | MOPY | MOORE OIL COMPANY INC | | | SCAC4 |
| 6454 | MOPZ | FLEXI-VAN LEASING | | | PWRC |
| 6455 | MOPZ | Flexi-Van Leasing | | | RSRV |
| 6456 | MOPZ | FLEXI-VAN LEASING INC | | | SCAC4 |
| 6457 | MOQA | MORENO CARO, ALBERTO | | | SCAC4 |
| 6458 | MOQE | MOORE TRANSPORTATION | | | SCAC4 |
| 6459 | MOQI | MARROQUIN INVESTMENTS LLC | | | SCAC4 |
| 6460 | MOQM | MOORE, TOM TRANSPORTATION | | | SCAC4 |
| 6461 | MOR | Morelfy A.S. | Callsign: Morefly, | FIN | AVCODES |
| 6462 | MOR | Aerolineas De Morelia | | | ICAO1 |
| 6463 | MOR | MITSUI O.S.K. LINES, LTD. | | | PWRC |
| 6464 | MORC | MONROE CONTRACTORS EQUIPMENT, INC | | | SCAC1 |
| 6465 | MORC | MONROE CONTRACTORS EQUIPMENT (DIV O | | | SCAC4 |
| 6466 | MORD | MOREAU TRANSPORT | | | SCAC4 |
| 6467 | MORE | MORRELLE TRANSFER INC | | | SCAC4 |
| 6468 | MORG | MORGAN OIL COMPANY | | | SCAC4 |
| 6469 | MORH | MORRIS TRANSPORT LLC | | | SCAC4 |
| 6470 | MORIS | MORIS s.r.o. | | SK | VKM |
| 6471 | MORL | MORALES, LOURDES AND OSCAR HERNANDE | | | SCAC4 |
| 6472 | MORN | MORRELL ENTERPRISES LP | | | SCAC4 |
| 6473 | MORQ | MARTINEZ VEGA, JOSE A | | | SCAC4 |
| 6474 | MORR | MORRELL TRANSFER, INC | | | SCAC1 |
| 6475 | MORT | MORRIS TRUCKING | | | SCAC4 |
| 6476 | MORU | MITSUI O.S.K. LINES LTD | | J | BIC |
| 6477 | MORU | ORMA SERVICES, B.V. | | | SCAC3 |
| 6478 | MORU | MITSUI O S K LINES LTD | | | SCAC4 |
| 6479 | MORW | MOORE TRANSPORTATION SERVICES INC | | | SCAC4 |
| 6480 | MORX | North American Car Corp. | added 7/1955; 10/1957-1/1975; eliminated 4/1976 | | NAKINA |
| 6481 | MORX | Mather Stock Car Co. | 1/1941-7/1954; eliminated 7/1955 | | NAKINA |
| 6482 | MORX | Mather Stock Car Co. | 1/52; eliminated 7/55 | | NRHS |
| 6483 | MORX | North American Car Corp. | added 7/55; 10/57-1/75; eliminated 4/76 | | NRHS |
| 6484 | MORX | JOHN MORRELL & CO. (NACCO [MATHER STOCK CAR CO.]) | | | PWRC |
| 6485 | MORZ | (MOLU) MITSUI O.S.K. LINES, LTD. | | | PWRC |
| 6486 | MORZ | Mitsui O.S.K. Lines | | | RSRV |
| 6487 | MORZ | MITSUI O.S.K. LINES, LTD. | | | SCAC4 |
| 6488 | MOS | Misr Overseas Airways | | ET | AVCODES |
| 6489 | MOS | Misr Overseas Airways | | | ICAO1 |
| 6490 | MOS | MITSUI O.S.K. LINES, LTD. | | | PWRC |
| 6491 | MOS | Horst Mosolf GmbH&Co. KG | | DE | VKM |
| 6492 | MOSC | MOSES ENTERPRISE CORP | | | SCAC4 |
| 6493 | MOSD | MOSLEY, D TRUCKING INC | | | SCAC4 |
| 6494 | MOSE | MORLEY SERVICE, INC. | | | PWRC |
| 6495 | MOSE | MOSER, ELMER & SONS LLC | | | SCAC4 |
| 6496 | MOSG | MISSOURI SUGARS LLC | | | SCAC4 |
| 6497 | MOSI | MOS INC OF MEXICO S DE RL DE CV | | | SCAC4 |
| 6498 | MOSK | MITSUI O.S.K. LINES, LTD. | | | PWRC |
| 6499 | MOSK | MOSKOWITZ MOTOR TRANSPORTATION, INC | | | SCAC1 |
| 6500 | MOSK | MOSKOWITZ MOTOR TRANSPORTATION, INC | | | SCAC4 |
