| 1 | NPKX | NPK-Tex, Inc. | added 7/1980; eliminated 7/1981 | | NAKINA |
| 2 | NPKX | General American Transportation Corp. | 7/1937-4/1961; eliminated 10/1962 | | NAKINA |
| 3 | NPKX | The Nuckolls Packing Co. (North American Car Corp.) | 7/1935 | | NAKINA |
| 4 | NPKX | The Nuckolls Packing Co. | 7/1930-7/1932 | | NAKINA |
| 5 | NPKX | The Nuckolls Packing Co. (General American Transportation Corp.) | Apr-38 | | NRHS |
| 6 | NPKX | General American Transportation Corp. | 1/52-4/61 | | NRHS |
| 7 | NPKX | NPK-Tex, Inc. | added 7/80; eliminated 7/81 | | NRHS |
| 8 | NPKX | *NUCKOLLS PACKING CO. (GENERAL AMERICAN TRANSPORTATION CORP.) | | | PWRC |
| 9 | NPKX | *NPK-TEX, INC. | | | PWRC |
