| 1 | PGCX | Poly Grinders Corp. | added 7/1977; 1/1980; eliminated 7/1981 | | NAKINA |
| 2 | PGCX | Peoples Gas Systems, Inc. | added 10/1985; 1/1994-7/2000; eliminated 4/2001; 7/2005 (not listed) | | NAKINA |
| 3 | PGCX | General American Transportation Corp. | 7/1937 (not listed) | | NAKINA |
| 4 | PGCX | Poly Grinders Corp. | added 7/77; 1/80; eliminated 7/81 | | NRHS |
| 5 | PGCX | Peoples Gas Systems, Inc. | 1/94-7/2000; eliminated 4/2001 | | NRHS |
| 6 | PGCX | *GENERAL AMERICAN TRANSPORTATION CORP. | | | PWRC |
| 7 | PGCX | *POLY GRINDERS CORP. | | | PWRC |
| 8 | PGCX | *PROCTOR & GAMBLE CELLULOSE | | | PWRC |
| 9 | PGCX | +PEOPLES GAS SYSTEM, INC. | | | PWRC |
| 10 | PGCX | Peoples Gas System | | | RSRV |
| 11 | PGCX | HERITAGE OPERATING L P | | | SCAC4 |
