| 501 | Leon J. Sabean | | Oil & Gas Operator | Dec 2018 |
| 502 | Leonard 1&2 LLC | | Oil Operator | Mar 2025 |
| 503 | Les Miller | | Oil & Gas Operator | Dec 1991 |
| 504 | Lesco Corp. | | Oil Operator | Dec 2000 |
| 505 | Linn Western Operating Inc. | | Oil & Gas Operator | Jan 2018 |
| 506 | Lion Oil & Gas Company LLC | | Oil & Gas Operator | Dec 1993 |
| 507 | Little Creek Properties Inc. | | Oil Operator | Feb 2025 |
| 508 | Little Jewel LLC | | Oil & Gas Operator | Feb 2025 |
| 509 | Lobo Operations LLC | | Oil Operator | Mar 2025 |
| 510 | Lobodo Inc. | | Oil & Gas Operator | Apr 2003 |
| 511 | Lodi Gas Storage L.L.C. | | Gas Operator | Mar 2025 |
| 512 | Lomax Exploration Company | Roosevelt, UT 84066 | Oil & Gas Operator | Jun 1995 |
| 513 | Lone Eagle LLC | | Oil & Gas Operator | Dec 2003 |
| 514 | Lonestar Foundation Inc. | | Oil Operator | Dec 2008 |
| 515 | Long Beach Oil Development Co | Glendale, CA 91203 | Oil & Gas Operator | Jun 2004 |
| 516 | Longbow LLC | | Oil & Gas Operator | Mar 2025 |
| 517 | Longview Production Company | Dallas, TX 75243-3795 | Oil & Gas Operator | Feb 2025 |
| 518 | Los Angeles Unified School District | | Oil Operator | Dec 2014 |
| 519 | Lyon Canyon Oil Corp. | | Oil & Gas Operator | Dec 1986 |
| 520 | M & B Oil Company | Holliday, TX 76366 | Oil & Gas Operator | Feb 2025 |
| 521 | M & J Operator | | Oil & Gas Operator | Mar 2025 |
| 522 | M. D. & G. Partnership | | Oil & Gas Operator | Dec 1996 |
| 523 | M. H. Whittier Energy LLC | | Oil & Gas Operator | Sep 1996 |
| 524 | M.T. Oil Co. | Copan, OK 74022 | Oil Operator | Feb 2025 |
| 525 | Macpherson Oil Company | | Oil & Gas Operator | Feb 2025 |
| 526 | Macpherson Operating Company L.P. | | Oil & Gas Operator | Feb 2025 |
| 527 | Magness Petroleum Company | | Oil & Gas Operator | Dec 1994 |
| 528 | Manley Energy Resources LLC | | Oil Operator | Jan 2018 |
| 529 | Maranatha Petroleum Inc. | | Oil & Gas Operator | Feb 2025 |
| 530 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Mar 2025 |
| 531 | Marathon Oil Company Operator | | Oil & Gas Operator | Dec 1993 |
| 532 | Maria L. Andrade | | Oil Operator | Dec 2006 |
| 533 | Marina Pacifica Oil Company | | Oil & Gas Operator | Dec 1981 |
| 534 | Mariposa Petroleum Co. | | Gas Operator | Dec 1980 |
| 535 | Marlin Pacific Oil & Gas | | Oil & Gas Operator | Dec 2003 |
| 536 | Marlyn Company | | Oil & Gas Operator | Dec 2009 |
| 537 | Marmac Resources Co. | | Oil & Gas Operator | Mar 2015 |
| 538 | Mary E. Wertalla | | Oil Operator | Dec 1984 |
| 539 | Matrix Oil Corporation | | Oil & Gas Operator | Mar 2025 |
| 540 | Mattco Petroleum | | Oil & Gas Operator | Dec 1988 |
| 541 | Mauro J. Dentino | | Oil Operator | Feb 2025 |
| 542 | Maxim Resources LTD U.S.A. | | Oil & Gas Operator | Dec 1997 |
| 543 | Maxoil Inc. | | Oil & Gas Operator | Dec 2004 |
| 544 | Maxus Exploration Company | Dallas, TX 75201 | Oil & Gas Operator | Jan 1995 |
| 545 | Maya Oil LLC | | Oil Operator | Feb 2025 |
| 546 | McBo Oil Co. | | Oil & Gas Operator | Dec 1996 |
| 547 | McDonald Ranch Partnership | | Oil Operator | Mar 2025 |
| 548 | McFarland Energy, Inc. | New Orleans, LA 70160 | Oil & Gas Operator | Dec 2009 |
| 549 | McKean Bros. | | Oil & Gas Operator | Dec 1997 |
| 550 | McKenzie & Assoc. | | Gas Operator | Dec 1990 |
| 551 | McLennan Family Properties LLP | | Oil & Gas Operator | Dec 2021 |
| 552 | McOr Oil & Gas Corp | Houston, TX 77002 | Oil & Gas Operator | Oct 2013 |
| 553 | Medallion Calif Properties Co. | | Oil & Gas Operator | Dec 2003 |
| 554 | Mendell Davis Gas Partners LLC | | Oil & Gas Operator | Dec 2013 |
| 555 | Mentren Corporation | | Gas Operator | Mar 2025 |
| 556 | Meritage Homes Of California Inc. | | Oil Operator | Dec 2020 |
| 557 | Midway-Sunset Investors LLC | | Oil & Gas Operator | Mar 2025 |
| 558 | Mills Oil Co. | | Oil Operator | Dec 1986 |
| 559 | Mission Oil Company | | Oil & Gas Operator | Feb 2025 |
| 560 | Mission Resources | | Oil & Gas Operator | Dec 1991 |
| 561 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 562 | Mitchell Oil | | Oil Operator | Feb 2025 |
| 563 | Mitchell-Grossu Oil Co. | | Oil & Gas Operator | Sep 2023 |
| 564 | Mitchwil Investments LLC | | Oil & Gas Operator | Dec 2019 |
| 565 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2016 |
| 566 | Mobil Oil Exploration & Production North America Inc. | | Oil & Gas Operator | Dec 1996 |
| 567 | Modus Inc. | | Oil & Gas Operator | Mar 2025 |
| 568 | Monterey Resources Inc. | | Oil & Gas Operator | Dec 1997 |
| 569 | Monument Production Inc. | | Oil & Gas Operator | Dec 2011 |
| 570 | Morrison Oil Co. LLC | | Oil & Gas Operator | Feb 2025 |
| 571 | Morton And Dolley | | Oil Operator | Dec 1991 |
| 572 | Mountain VIew Resources LLC | | Oil & Gas Operator | Mar 2025 |
| 573 | Murray-Teague Assoc. | | Oil Operator | Dec 2005 |
| 574 | Mutz Oil Operator | | Oil Operator | Dec 1988 |
| 575 | Naftex Operating Company | | Oil & Gas Operator | Mar 2025 |
| 576 | Nahama & Weagant Energy Company | | Oil & Gas Operator | Dec 1997 |
| 577 | Nana Oil & Gas Inc. | | Oil & Gas Operator | Jan 2018 |
| 578 | Nasco Petroleum L.L.C. | | Oil & Gas Operator | Mar 2025 |
| 579 | National Oil Company | Garden City, KS 67846 | Oil & Gas Operator | Jun 2024 |
| 580 | Natural Gas Corp. Of Calif. | | Oil & Gas Operator | Dec 1987 |
| 581 | Navitas Oil & Gas LLC | | Gas Operator | Dec 2012 |
| 582 | Neon Energy Corporation | | Oil Operator | Apr 2014 |
| 583 | New Chaparral Petroleum Inc. | | Oil & Gas Operator | Dec 2005 |
| 584 | New-Lonamen | | Oil & Gas Operator | Dec 2008 |
| 585 | Newbridge Resources, LLC | Houston, TX 77056 | Oil & Gas Operator | Mar 2025 |
| 586 | Newmo Company | | Oil & Gas Operator | Dec 2001 |
| 587 | NGC Energy Co. | | Oil & Gas Operator | May 1989 |
| 588 | NMT Oil Company Inc. | | Oil & Gas Operator | Mar 2025 |
| 589 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | May 2025 |
| 590 | Nordic Oil Company | | Oil & Gas Operator | Dec 1999 |
| 591 | North Of River Sanitary District | | Oil & Gas Operator | Dec 2002 |
| 592 | North Valley Gaswell Services | | Gas Operator | Feb 2025 |
| 593 | North Valley Oil & Gas Co. | | Oil & Gas Operator | Dec 1996 |
| 594 | Northern Energy Devel. Co. | | Gas Operator | Dec 1995 |
| 595 | Northern Michigan Expl Co | | Oil & Gas Operator | Jul 1990 |
| 596 | Northstar Resources Inc. | | Gas Operator | Feb 2025 |
| 597 | Northwest Petroleum Inc. | | Oil & Gas Operator | Feb 2025 |
| 598 | Nuwi-Bayshore LLC | | Oil & Gas Operator | Dec 1999 |
| 599 | Ny Oil Inc. | | Oil Operator | Dec 2025 |
| 600 | O'Brien-Sill | | Oil & Gas Operator | Mar 2025 |