| 401 | Hillside Oil Partners | | Oil & Gas Operator | Dec 1999 |
| 402 | Hiwa Petroleum Corp. | | Oil & Gas Operator | Mar 2025 |
| 403 | Hoag Memorial Hospital Presbyterian | | Gas Operator | Mar 2025 |
| 404 | Hoc Ca LLC | | Oil & Gas Operator | Apr 2025 |
| 405 | Holmes Western Oil Corporation | | Oil & Gas Operator | Mar 2025 |
| 406 | Horizon Operating Co. | | Oil & Gas Operator | Dec 1995 |
| 407 | Howard E. Caywood Inc. | | Oil & Gas Operator | Mar 2025 |
| 408 | Hoyt Energy L.L.C. | | Oil Operator | Feb 2025 |
| 409 | Hrubetz Oil Co. | Dallas, TX 75225 | Oil Operator | Sep 1986 |
| 410 | Hubl/Harbin | | Oil Operator | Dec 1994 |
| 411 | Hunt Enterprises | | Oil & Gas Operator | Feb 2025 |
| 412 | Hunter Edison Oil Development Limited Partnership | | Oil & Gas Operator | Mar 2025 |
| 413 | Huntington Beach Company | | Oil & Gas Operator | Dec 1998 |
| 414 | Huntington Beach Pacific Coast Enterprises LLC | | Oil & Gas Operator | Jan 2018 |
| 415 | Huntington Signal Oil Company | | Oil & Gas Operator | Dec 1997 |
| 416 | Husky Oil Company | Cody, WY 82414 | Oil & Gas Operator | Dec 1984 |
| 417 | Hvi Cat Canyon Inc. | | Oil & Gas Operator | Feb 2025 |
| 418 | Illini Development Company | | Oil & Gas Operator | Dec 2002 |
| 419 | Imperial Occidental | | Oil & Gas Operator | Feb 2025 |
| 420 | Incremental Oil & Gas USA Holdings Inc | Denver, CO 80202 | Oil & Gas Operator | Apr 2021 |
| 421 | Independent Exploration Company | | Oil & Gas Operator | Dec 2000 |
| 422 | Inland Petroleum Company | | Oil & Gas Operator | Dec 1997 |
| 423 | Innex California Inc. | | Oil & Gas Operator | Feb 2025 |
| 424 | Instrat Inc. | | Oil & Gas Operator | Dec 1992 |
| 425 | Inter-American Petroleum | | Oil & Gas Operator | Dec 2006 |
| 426 | Intercontinental Tech Group Inc. | | Oil & Gas Operator | Dec 2004 |
| 427 | Irani Engineering | | Gas Operator | Dec 1995 |
| 428 | Island Energy Partners LLC | | Gas Operator | Jan 2018 |
| 429 | J & K Operating Company Inc. | | Oil & Gas Operator | Mar 2025 |
| 430 | J & M Operators | | Oil & Gas Operator | Dec 1997 |
| 431 | J And J Operators LLC | | Oil & Gas Operator | Mar 2025 |
| 432 | J. E. Baker | | Oil Operator | Dec 1998 |
| 433 | J. I. Hathaway Opr. | | Oil & Gas Operator | Dec 1988 |
| 434 | J. L. Davis | | Oil & Gas Operator | Dec 1985 |
| 435 | J. M. Peters Co. Inc. | | Oil & Gas Operator | Dec 1990 |
| 436 | J. M. Van Horn Operator | | Oil Operator | Dec 1989 |
| 437 | J.P. Oil Company LLC | | Oil & Gas Operator | Feb 2025 |
| 438 | Jacat Oil Co. | | Oil Operator | Dec 1990 |
| 439 | Jaco Production Company | Bakersfield, CA 93380 | Oil Operator | Feb 2025 |
| 440 | James C. Thomas III | | Oil & Gas Operator | Dec 1989 |
| 441 | James S. Anderson | | Oil & Gas Operator | Feb 2025 |
| 442 | James Sherman & Dennis Weese | | Oil & Gas Operator | Feb 2025 |
| 443 | Jean Martinez | | Oil Operator | Feb 2025 |
| 444 | Jeanne E. Nevins | | Oil Operator | Dec 2000 |
| 445 | Jeans Well Service | | Gas Operator | Dec 1985 |
| 446 | Jim Graham | | Oil & Gas Operator | Jan 2018 |
| 447 | John A. Thomas | | Oil & Gas Operator | Feb 2025 |
| 448 | John A. Thomas & Linda Thomas | | Oil Operator | Feb 2025 |
| 449 | John Guzman Crane Service Inc. | | Oil & Gas Operator | Mar 2025 |
| 450 | John L. Sowers | | Oil & Gas Operator | Dec 2009 |
| 451 | John M. & W. F. Rohrig | | Oil Operator | Dec 1986 |
| 452 | John N. Dewitt & Paul Graham | | Gas Operator | Dec 1989 |
| 453 | John O. Richardson Operator | | Oil & Gas Operator | Mar 2025 |
| 454 | John Pestana Family Trust | | Oil & Gas Operator | Dec 1994 |
| 455 | John Tedesco | | Oil & Gas Operator | Mar 2025 |
| 456 | Jordan Oil & Gas Company | Healdsburg, CA 95448-1919 | Oil & Gas Operator | Mar 1995 |
| 457 | Joro Inc. | | Oil & Gas Operator | Feb 2025 |
| 458 | JXR Company | | Oil Operator | Dec 1991 |
| 459 | K & J Oil Co. Inc. | | Oil & Gas Operator | Feb 2025 |
| 460 | K. G. H. Enterprises | | Oil Operator | Dec 2003 |
| 461 | K. J. Enterprises LLC | | Oil Operator | Dec 2001 |
| 462 | Kaiser Energy Inc | Denver, CO 80202 | Oil & Gas Operator | Dec 1990 |
| 463 | Kaiser-Francis Oil Company | Tulsa, OK 74121 | Oil & Gas Operator | May 2025 |
| 464 | Kaye R. McCown | | Oil Operator | Jun 2012 |
| 465 | KB Oil & Gas | | Oil & Gas Operator | Feb 2025 |
| 466 | KC Resources Inc | Snowmass VLG., CO 81615 | Oil & Gas Operator | Feb 2025 |
| 467 | Kelpetro Operating Inc. | | Oil & Gas Operator | Dec 2021 |
| 468 | Kelt Oil & Gas, Inc. | Torrance, CA 90503 | Oil & Gas Operator | Dec 2003 |
| 469 | Kem Enterprise Inc. | | Oil & Gas Operator | Mar 2025 |
| 470 | Kenneth H. Hunter Jr. | | Oil & Gas Operator | Dec 1991 |
| 471 | Kenneth H. Hunter Jr. Trustee Of The Hunter Living Trust | | Oil & Gas Operator | Dec 2001 |
| 472 | Kenneth Lopez And Conway Lopez | | Oil & Gas Operator | Feb 2025 |
| 473 | Kenneth Sperry | | Oil & Gas Operator | Dec 1992 |
| 474 | Kern Front-Section 35-Partners | | Oil & Gas Operator | Feb 2025 |
| 475 | Kern River Holdings II LLC | | Oil & Gas Operator | Mar 2025 |
| 476 | Kernview Oil Co. | | Oil & Gas Operator | Dec 2003 |
| 477 | Key Production Company, Inc. | Longview, TX 75606 | Oil & Gas Operator | Mar 2025 |
| 478 | KLD Energy | | Oil & Gas Operator | Dec 2015 |
| 479 | KMD Operating Company LLC | | Oil & Gas Operator | Dec 2015 |
| 480 | KMP Operating Inc. | | Oil Operator | Mar 2025 |
| 481 | Koch Exploration Company | Houston, TX 77046 | Oil & Gas Operator | Jan 2025 |
| 482 | Kore Energy LLC | | Oil & Gas Operator | Feb 2025 |
| 483 | Kraemer II LLC | | Oil & Gas Operator | Dec 2000 |
| 484 | Krummrich Engineering Corporation | | Oil & Gas Operator | Feb 2025 |
| 485 | L & M Oil Co. | Yates Center, KS 66783 | Oil & Gas Operator | Dec 1998 |
| 486 | L P Oil Company Inc. | | Oil & Gas Operator | Mar 2025 |
| 487 | L. W. Babcock | | Oil Operator | Dec 1986 |
| 488 | La Honda Fields Limited Partnership | | Oil & Gas Operator | Dec 2021 |
| 489 | La Land Co. | | Oil Operator | Dec 1989 |
| 490 | La Paloma Generating Company LLC | | Oil & Gas Operator | Dec 2000 |
| 491 | Laguna County Sanitation District | | Oil & Gas Operator | Dec 2003 |
| 492 | Lario Oil & Gas Company | Odessa, TX 79762 | Oil & Gas Operator | May 2025 |
| 493 | Larry E. Bedrosian | | Oil Operator | Dec 1999 |
| 494 | Las Palmas Petroleum Corp. | | Oil Operator | Dec 2010 |
| 495 | Laymac Corporation | | Gas Operator | Dec 2020 |
| 496 | LBTH Inc. | | Oil & Gas Operator | Mar 2025 |
| 497 | LDD Energy LLC | | Oil & Gas Operator | Feb 2025 |
| 498 | Lee And Jane Laird | | Oil & Gas Operator | Dec 2002 |
| 499 | Lee Lamberson Inc. | | Oil & Gas Operator | Dec 2000 |
| 500 | Legacy Energy Inc | Carpinteria, CA 93013 | Oil & Gas Operator | Jun 2012 |