| 1 | ISC | Island Air Charters, Inc. | Callsign: Barracuda, | USA | AVCODES |
| 2 | ISC | Interporto Servizio Cargo | | I | TRAFFIC |
| 3 | ISC | ISC-INTERPORTO Servizi Cargo S.P.A. | | IT | VKM |
| 4 | ISCB | ISABELLA SHIPPING COMPANY | | | SCAC1 |
| 5 | ISCB | ISABELLA SHIPPING COMPANY LTD BERMU | | | SCAC4 |
| 6 | ISCC | INTERNATIONAL SHIPPING COMPANY INC. | | | SCAC4 |
| 7 | ISCF | INTERNATIONAL STONE CONCEPTS | | | SCAC4 |
| 8 | ISCG | INDUSTRIAL SERVICES CONTRACTORS INC | | | SCAC4 |
| 9 | ISCI | INTERNATIONAL TRANSPORT EXPRESS COR | | | SCAC4 |
| 10 | ISCL | INDIA STEAMSHIP (A DIV OF | | | SCAC4 |
| 11 | ISCO | INTERMODAL SALES CORPORATION | | | SCAC4 |
| 12 | ISCP | INSTRON CORP | | | SCAC4 |
| 13 | ISCQ | INTEGRITY SHIPPING CORP | | | SCAC4 |
| 14 | ISCR | INLAND SEAFOOD CORP | | | SCAC4 |
| 15 | ISCT | INTRINSIC TRANSPORT INC | | | SCAC4 |
| 16 | ISCU | STAR CONTAINER SPAIN S.A. | | E | BIC |
| 17 | ISCU | I.S.C. CHEMICALS LTD. | | | PWRC |
| 18 | ISCU | I.S.C. Chemicals | | | RSRV |
| 19 | ISCX | ISC, Inc. | 1/1994-7/2005 | | NAKINA |
| 20 | ISCX | Interlake, Inc. | added 4/1971; 1/1975; eliminated 7/1976 | | NAKINA |
| 21 | ISCX | Interlake Steel Corp. | added 7/1965 (reporting marks changed from IICX); 7/1965-10/1966; eliminated 10/1967 | | NAKINA |
| 22 | ISCX | International Sugar Co. | eliminated 10/1960 | | NAKINA |
| 23 | ISCX | Imperial Sugar Co. | added 7/1960 | | NAKINA |
| 24 | ISCX | Carnegie-Illinois Steel Corp. | 7/1937-4/1938 | | NAKINA |
| 25 | ISCX | Illinois Steel Co. | 7/1935 | | NAKINA |
| 26 | ISCX | Illinois Steel Co. Tank Line | 8/1920-7/1932 | | NAKINA |
| 27 | ISCX | Illinois Steel Co. (Carnegie-Illinois Steel Corp.) | Apr-38 | | NRHS |
| 28 | ISCX | Imperial Sugar Co. | added 7/60 | | NRHS |
| 29 | ISCX | International Sugar Co. | eliminated 10/60 | | NRHS |
| 30 | ISCX | Interlake Steel Corp. | added 7/65 (reporting marks changed from IICX); 7/65-10/66; eliminated 10/67 | | NRHS |
| 31 | ISCX | Interlake, Inc. | added 4/71; 1/75; eliminated 7/76 | | NRHS |
| 32 | ISCX | ISC, Inc. | 1/94-7/2000 | | NRHS |
| 33 | ISCX | *CARNEGIE-ILLINOIS STEEL CORP. [ILLINOIS STEEL CO. TANK LINE] | | | PWRC |
| 34 | ISCX | *INTERNATIONAL SUGAR CO. [IMPERIAL SUGAR CO.] | | | PWRC |
| 35 | ISCX | *INTERLAKE, INC. [INTERLAKE STEEL CORP.] | | | PWRC |
| 36 | ISCX | +ISC, INC. | | | PWRC |
| 37 | ISCX | Illinois Steel Company (ISC Inc.) | | | RSRV |
| 38 | ISCX | ISC INC | | | SCAC4 |
