| 1 | SIG | Signature Aircraft Charter | Callsign: Signature, | GB | AVCODES |
| 2 | SIGB | SOLAI CARTAGE INC | | | SCAC4 |
| 3 | SIGD | SISTEMAS INTEGRALES DE LOGISTICA | | | SCAC4 |
| 4 | SIGE | SIORDIA, GUILLERMO EDUARDO | | | SCAC4 |
| 5 | SIGF | SIGMA FREIGHT INC | | | SCAC4 |
| 6 | SIGG | SIGGINS OIL COMPANY | | | SCAC4 |
| 7 | SIGH | SIG LOGISTICS | | | SCAC4 |
| 8 | SIGI | SPRINGS GLOBAL US INC | | | SCAC4 |
| 9 | SIGM | SIGMA LOGISTICS INC | | | SCAC4 |
| 10 | SIGMA | SIGMA Sp. z o.o. | | PL | TRAFFIC |
| 11 | SIGO | SIGURDSON FARMS GIMLI LTD | | | SCAC4 |
| 12 | SIGP | SIGNATURE PLASTICS LLC | | | SCAC4 |
| 13 | SIGQ | SPIRIT STORAGE INC | | | SCAC4 |
| 14 | SIGR | SIGNATURE TRUCK LINES INC | | | SCAC4 |
| 15 | SIGT | SIGNOR TRUCKING INC | | | SCAC4 |
| 16 | SIGU | SINOAGE INTERNATIONAL LIMITED | | HK | BIC |
| 17 | SIGU | STERLING INTERNATIONAL MOVERS | | | SCAC4 |
| 18 | SIGX | Signal Gasoline Co. | 7/1932 | | NAKINA |
| 19 | SIGX | Southern Indiana Gas and Electric Co. | added 4/1979; 1/1980-7/2000; eliminated 7/2002; 7/2005 (not listed) | | NAKINA |
| 20 | SIGX | Southern Indiana Gas and Electric Co. | added 4/79; 1/80-7/2000 | | NRHS |
| 21 | SIGX | *SIGNAL GASOLINE CO. | | | PWRC |
| 22 | SIGX | +SOUTHERN INDIANA GAS & ELECTRIC CO. | | | PWRC |
| 23 | SIGX | Southern Indiana Gas and Electric | | | RSRV |
| 24 | SIGX | SOUTHERN INDIANA GAS & ELECTRIC CO. | | | SCAC4 |
