| 1 | ISPC | ISLAND PRECISION MANUFACTURING LTD | | | SCAC4 |
| 2 | ISPN | ISP | | | SCAC4 |
| 3 | ISPO | ISPOR | | | SCAC4 |
| 4 | ISPR | INTERNATIONAL SPECIALTY PRODUCE INC | | | SCAC4 |
| 5 | ISPT | INDY SPECIALIZED TRANSPORT INC | | | SCAC4 |
| 6 | ISPV | ITALSEMPIONE SPA | | | SCAC4 |
| 7 | ISPX | International Specialty Products | 7/2005 (not listed); added 10/2007 | | NAKINA |
| 8 | ISPX | The Western Company of North America | added 4/1980; eliminated 7/1992; 1/1994 (not listed) | | NAKINA |
| 9 | ISPX | United States Silica Corp. | added 10/1978; 1/1980; eliminated 1/1980 | | NAKINA |
| 10 | ISPX | Iron & Steel Products Inc. | 7/1937-1/1946 (not listed); 1/1950; 1/1952-7/1954 (not listed); added 10/1955; eliminated 10/1956 | | NAKINA |
| 11 | ISPX | Iron & Steel Products Inc. | Jan-52 | | NRHS |
| 12 | ISPX | United States Silica Corp. | added 10/78; 1/80; eliminated 1/80 | | NRHS |
| 13 | ISPX | The Western Company of North America | added 4/80; eliminated 7/92; 1/94 | | NRHS |
| 14 | ISPX | *IRON & STEEL PRODUCTS INC. | | | PWRC |
| 15 | ISPX | *WESTERN COMPANY OF NORTH AMERICA [UNITED STATES SILICA CORP.] | | | PWRC |
| 16 | ISPX | +INTERNATIONAL SPECIALTY PRODUCTS | | | PWRC |
| 17 | ISPX | Western of North America | | | RSRV |
| 18 | ISPX | INTERNATIONAL SPECIALITY PRODUCTS | | | SCAC4 |
| 19 | ISPZ | ISU POWER PLANT | | | PWRC |
