| 6901 | MPPX | MONTANA PHOSPHATE PRODUCTS CO. | | | PWRC |
| 6902 | MPPY | METRO PARTS COMPANY | | | SCAC4 |
| 6903 | MPPZ | MOBA POWER PLANT | | | PWRC |
| 6904 | MPQC | MAP LOGISTICS INC | | | SCAC4 |
| 6905 | MPQG | MP LOGISTICS LLC | | | SCAC4 |
| 6906 | MPQI | MULTI PURPOSE LOGISTICS INC | | | SCAC4 |
| 6907 | MPQL | MAP LOGISTICS LLC | | | SCAC4 |
| 6908 | MPR | Empire Aviation Services Limited | IATA Prefix: 869, | WAN | AVCODES |
| 6909 | MPR | Empire Aviation Services | | | ICAO1 |
| 6910 | MPRA | MOPARTS INC | | | SCAC4 |
| 6911 | MPRC | MARYLAND & PENNSYLVANIA RAILROAD | | | PWRC |
| 6912 | MPRD | MADRID PRODUCE | | | SCAC4 |
| 6913 | MPRE | MEMPHI | | | SCAC4 |
| 6914 | MPRF | MAPLE RIDGE FARM | | | SCAC4 |
| 6915 | MPRH | MPR TRANSPORT | | | SCAC4 |
| 6916 | MPRI | METROPOLITAN PAPER RECYCLING INC | | | SCAC4 |
| 6917 | MPRL | MAPLE PRO | | | SCAC4 |
| 6918 | MPRN | MARQUARD | | | SCAC4 |
| 6919 | MPRO | MET-PRO SHIPPING CORP | | | SCAC4 |
| 6920 | MPRQ | MPR SUPPLY CHAIN SOLUTIONS | | | SCAC4 |
| 6921 | MPRU | MEDITERRANEA | | | SCAC4 |
| 6922 | MPRW | MCASPHA | | | SCAC4 |
| 6923 | MPRX | Motive Power Equipment and Solutins, Inc. | 7/2005 (not listed) | | NAKINA |
| 6924 | MPRX | Montana Power Co. | 1/1952-10/1957; eliminated 10/1960 | | NAKINA |
| 6925 | MPRX | Miller Petroleum Co. | 7/1923 | | NAKINA |
| 6926 | MPRX | The Miller Petroleum Refining Co. | 8/1920 | | NAKINA |
| 6927 | MPRX | Montana Power Co. | 1/52-10/57; eliminated 10/60 | | NRHS |
| 6928 | MPRX | *MILLER PETROLEUM CO. | | | PWRC |
| 6929 | MPRX | *MONTANA POWER CO. | | | PWRC |
| 6930 | MPRX | +MOTIVE POWER EQUIPMENT & SOLUTIONS, INC. | | | PWRC |
| 6931 | MPRX | Motive Power & Equipment Solutions | | | RSRV |
| 6932 | MPRX | MOTIVE POWER EQUIPMENT AND SOLUTION | | | SCAC4 |
| 6933 | MPS | Metropolis Noord I.B.V. | IATA: DN, Callsign: Metro Regional, | NL | AVCODES |
| 6934 | MPS | Aviajet | | GB | AVCODES |
| 6935 | MPS | Metropoliatn Police Air Support Unit | Callsign: Special, | GB | AVCODES |
| 6936 | MPS | Metroplis | | | ICAO1 |
| 6937 | MPSA | MARSTON, P S ASSOCIATES LLC | | | SCAC4 |
| 6938 | MPSB | Mecklenburg-Pommersche Schmalspurbahn-Freunde e.V. | Schwichtenberg | D | privat-bahn.de |
| 6939 | MPSB | MAX POWER SHIPPING LIMITED | | | SCAC4 |
| 6940 | MPSB | | | DDR | TRAFFIC |
| 6941 | MPSC | MISSOURI PUBLIC SERVICE CO. | | | PWRC |
| 6942 | MPSD | MULTIPAK POSTAL SERVICE INC | | | SCAC4 |
| 6943 | MPSE | MPS ENTERPRISES INC | | | SCAC4 |
| 6944 | MPSF | MAPLE STONE FARM | | | SCAC4 |
| 6945 | MPSG | MCCORMACK | | | SCAC4 |
| 6946 | MPSJ | MOBILE PRODUCTION SERVICE INC | | | SCAC4 |
| 6947 | MPSK | MPS TRUCK LINES | | | SCAC4 |
| 6948 | MPSN | METRO EXPEDITE | | | SCAC4 |
| 6949 | MPSO | MASURIA PEARL SHIPPING GMBH & CO KG | | | SCAC4 |
| 6950 | MPSP | MAPLE STAR TRANSPORT LTD | | | SCAC4 |
| 6951 | MPSS | MALPASS | | | SCAC4 |
| 6952 | MPSU | MODULAR PONTOON SYSTEMS BV | | NL | BIC |
| 6953 | MPSV | MATERIAUX PAYSAGERS SAVARIA LTEE | | | SCAC4 |
| 6954 | MPSX | Missouri Public Service | 7/2005; eliminated 1/2006 | | NAKINA |
| 6955 | MPSX | Missouri Public Service Co. | 1/1994-7/2000 | | NAKINA |
| 6956 | MPSX | Missouri Public Service | added 4/1989 | | NAKINA |
| 6957 | MPSX | Missouri Public Service Co. | added 10/1968; 4/1970-1/1980; eliminated 4/1989 | | NAKINA |
| 6958 | MPSX | Missouri Public Service Co. | added 10/68; 4/70-1/80; eliminated 4/89 | | NRHS |
| 6959 | MPSX | Missouri Public Service | added 4/89 | | NRHS |
| 6960 | MPSX | Missouri Public Service Co. | 1/94-7/2000 | | NRHS |
| 6961 | MPSX | *MISSOURI PUBLIC SERVICE CO. | | | PWRC |
| 6962 | MPSX | +AQUILA, INC. | | | PWRC |
| 6963 | MPSX | Missouri Public Service | | | RSRV |
| 6964 | MPSX | AQUILA INC | | | SCAC4 |
| 6965 | MPSZ | MISSOURI PUBLIC SERVICE CO. | | | PWRC |
| 6966 | MPT | Miapet-Avia | | | ICAO1 |
| 6967 | MPTA | M & P TRANSFER INC | | | SCAC4 |
| 6968 | MPTB | M P TRANSPORT | | | SCAC4 |
| 6969 | MPTC | MT. PLEASANT TRANSFER, INC | | | SCAC1 |
| 6970 | MPTD | MUTCH, P M LTD | | | SCAC4 |
| 6971 | MPTE | MARPOLE TRANSPORT LIMITED | | | SCAC4 |
| 6972 | MPTF | MAPLETREE TRANSPORTATION INC (BROKE | | | SCAC4 |
| 6973 | MPTG | METROPOLITAN TRUCKING INC | | | SCAC4 |
| 6974 | MPTH | MAGPIE TECHNOLOGY | | | SCAC4 |
| 6975 | MPTL | MISSOURI PACIFIC TRUCK LINES | | | PWRC |
| 6976 | MPTN | MARES POINT MARINE SERVICES INC | | | SCAC4 |
| 6977 | MPTO | MAP TRANSPORTATION INC | | | SCAC4 |
| 6978 | MPTP | MP TRANSPORT | | | SCAC4 |
| 6979 | MPTQ | MAPLETREE TRANSPORTATION INC | | | SCAC4 |
| 6980 | MPTR | MURPHY HAULING SERVICE, INC | | | SCAC1 |
| 6981 | MPTS | MILOS PRODUCT TANKER CORPORATION | | | SCAC4 |
| 6982 | MPTV | MARPORT C-TECH LTD | | | SCAC4 |
| 6983 | MPTX | Procor Ltd. | added 1/1974; 1/1975-7/2005 | | NAKINA |
| 6984 | MPTX | Union Tank Car Co. | added 7/1973; eliminated 1/1974 | | NAKINA |
| 6985 | MPTX | Magnolia Provision Co. | 8/1920-7/1923 | | NAKINA |
| 6986 | MPTX | Union Tank Car Co. | added 7/73; eliminated 1/74 | | NRHS |
| 6987 | MPTX | Procor Ltd. | added 1/74; 1/75-7/2000 | | NRHS |
| 6988 | MPTX | *MAGNOLIA PROVISION CO. | | | PWRC |
| 6989 | MPTX | +(PROX) PROCOR LIMITED [UNION TANK CAR CO.] | | | PWRC |
| 6990 | MPTX | Magnolia Provision Co. (Procor) | | | RSRV |
| 6991 | MPTX | PROCOR LIMITED | | | SCAC4 |
| 6992 | MPU | UP [MISSOURI PACIFIC RAILROAD] | | | PWRC |
| 6993 | MPU | Missouri Pacific Railroad (Union Pacific Railroad) | | | RSRV |
| 6994 | MPUS | MOVE-PRO U S A INC | | | SCAC4 |
| 6995 | MPVE | MPV EXPRESS INC | | | SCAC4 |
| 6996 | MPVI | MARTIN PAVING INC | | | SCAC4 |
| 6997 | MPWC | MURPHY PLYWOOD CO | | | SCAC4 |
| 6998 | MPWE | MPW EXPRESS LLC | | | SCAC4 |
| 6999 | MPWI | MPW INDUSTRIAL SERVICES INC | | | SCAC4 |
| 7000 | MPWL | M POWER LOGISTICS INC | | | SCAC4 |
