| 1 | MPRX | Motive Power Equipment and Solutins, Inc. | 7/2005 (not listed) | | NAKINA |
| 2 | MPRX | Montana Power Co. | 1/1952-10/1957; eliminated 10/1960 | | NAKINA |
| 3 | MPRX | Miller Petroleum Co. | 7/1923 | | NAKINA |
| 4 | MPRX | The Miller Petroleum Refining Co. | 8/1920 | | NAKINA |
| 5 | MPRX | Montana Power Co. | 1/52-10/57; eliminated 10/60 | | NRHS |
| 6 | MPRX | *MILLER PETROLEUM CO. | | | PWRC |
| 7 | MPRX | *MONTANA POWER CO. | | | PWRC |
| 8 | MPRX | +MOTIVE POWER EQUIPMENT & SOLUTIONS, INC. | | | PWRC |
| 9 | MPRX | Motive Power & Equipment Solutions | | | RSRV |
| 10 | MPRX | MOTIVE POWER EQUIPMENT AND SOLUTION | | | SCAC4 |
