| 1 | ISCX | ISC, Inc. | 1/1994-7/2005 | | NAKINA |
| 2 | ISCX | Interlake, Inc. | added 4/1971; 1/1975; eliminated 7/1976 | | NAKINA |
| 3 | ISCX | Interlake Steel Corp. | added 7/1965 (reporting marks changed from IICX); 7/1965-10/1966; eliminated 10/1967 | | NAKINA |
| 4 | ISCX | International Sugar Co. | eliminated 10/1960 | | NAKINA |
| 5 | ISCX | Imperial Sugar Co. | added 7/1960 | | NAKINA |
| 6 | ISCX | Carnegie-Illinois Steel Corp. | 7/1937-4/1938 | | NAKINA |
| 7 | ISCX | Illinois Steel Co. | 7/1935 | | NAKINA |
| 8 | ISCX | Illinois Steel Co. Tank Line | 8/1920-7/1932 | | NAKINA |
| 9 | ISCX | Illinois Steel Co. (Carnegie-Illinois Steel Corp.) | Apr-38 | | NRHS |
| 10 | ISCX | Imperial Sugar Co. | added 7/60 | | NRHS |
| 11 | ISCX | International Sugar Co. | eliminated 10/60 | | NRHS |
| 12 | ISCX | Interlake Steel Corp. | added 7/65 (reporting marks changed from IICX); 7/65-10/66; eliminated 10/67 | | NRHS |
| 13 | ISCX | Interlake, Inc. | added 4/71; 1/75; eliminated 7/76 | | NRHS |
| 14 | ISCX | ISC, Inc. | 1/94-7/2000 | | NRHS |
| 15 | ISCX | *CARNEGIE-ILLINOIS STEEL CORP. [ILLINOIS STEEL CO. TANK LINE] | | | PWRC |
| 16 | ISCX | *INTERNATIONAL SUGAR CO. [IMPERIAL SUGAR CO.] | | | PWRC |
| 17 | ISCX | *INTERLAKE, INC. [INTERLAKE STEEL CORP.] | | | PWRC |
| 18 | ISCX | +ISC, INC. | | | PWRC |
| 19 | ISCX | Illinois Steel Company (ISC Inc.) | | | RSRV |
| 20 | ISCX | ISC INC | | | SCAC4 |
