| 1 | HPLX | Exxon Mobil Corp. | added 7/2000; 7/2005 | | NAKINA |
| 2 | HPLX | Exxon Co., U.S.A. | added 1/1977; 1/1980; 1/1994; eliminated 7/2000 | | NAKINA |
| 3 | HPLX | Exxon Pipeline Co. | added 1/1973; 1/1975; eliminated 1/1977 | | NAKINA |
| 4 | HPLX | Humble Pipe Line Co. | added 1/1967; 4/1970; eliminated 1/1973 | | NAKINA |
| 5 | HPLX | Hyman Pickle Co. | 7/1923 | | NAKINA |
| 6 | HPLX | Humble Pipe Line Co. | added 1/67; 4/70 | | NRHS |
| 7 | HPLX | Exxon Pipeline Co. | 1/75; eliminated 1/77 | | NRHS |
| 8 | HPLX | Exxon Co., U.S.A. | added 1/77; 1/80; 1/94; eliminated 7/2000 | | NRHS |
| 9 | HPLX | Exxon Mobil Corp. | added 7/2000 | | NRHS |
| 10 | HPLX | *HYMAN PICKLE CO. | | | PWRC |
| 11 | HPLX | +EXXON-MOBIL CORP. [EXXON USA CORP.; EXXON PIPELINE CO.; HUMBLE PIPE LINE CO.] | | | PWRC |
| 12 | HPLX | Humble Pipe Line (Exxon-Mobil Corporation) | | | RSRV |
| 13 | HPLX | EXXON MOBIL CORPORATION | | | SCAC4 |