| 1 | HSM | Helicopter Service MTTE | Callsign: Lifestar, | D | AVCODES |
| 2 | HSM | Helicopter Services Malta Limited | Callsign: Helimalt, | M | AVCODES |
| 3 | HSM | Horizon Air for Transport and Training | | | ICAO1 |
| 4 | HSM | Dutch Iron Railway Company | | NL | TRAFFIC |
| 5 | HSMA | HARMONIA SHIPPING MANAGEMENT INC | | | SCAC4 |
| 6 | HSMC | HOLLANDER INTERNATIONAL STORAGE AND | | | SCAC4 |
| 7 | HSMG | HANDLING SPECIALTY MANUFACTURING LI | | | SCAC4 |
| 8 | HSMI | HEWITT, S M (SARNIA) LTD | | | SCAC4 |
| 9 | HSMN | HOLLYWOOD & SPORTS MEMORABILIA INC | | | SCAC4 |
| 10 | HSMX | Housmex, Inc. | added 1/1986; eliminated 7/1992; 1/1994 (not listed) | | NAKINA |
| 11 | HSMX | Housmex, Inc. | added 1/86; eliminated 7/92; 1/94 | | NRHS |
| 12 | HSMX | *HESSEN STEAM MUSEUM | | | PWRC |
| 13 | HSMX | *HOUSMEX, INC. | | | PWRC |
