| 401 | JN Exploration & Production LP | Billings, MT 59103 | Oil & Gas Operator | Jan 2001 |
| 402 | JN Production LLP | Guthrie, OK 73028 | Oil & Gas Operator | Apr 2025 |
| 403 | Jo-Allyn Oil Co Inc | Laverne, OK 73848 | Oil & Gas Operator | May 2025 |
| 404 | Johnson E Lyle | Oklahoma City, OK 73142 | Oil & Gas Operator | Apr 2025 |
| 405 | Johnson Exploration Company | Oklahoma City, OK 73102-7008 | Oil & Gas Operator | Jun 2015 |
| 406 | Jolen Operating Company | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2025 |
| 407 | Jones Oil Company LLC (The) | Duncan, OK 73533-4995 | Oil & Gas Operator | Mar 2025 |
| 408 | JW Exploration LLC Of Texas | Dallas, TX 75287-3329 | Oil & Gas Operator | Jun 2017 |
| 409 | K & F Oil Co. | Olney, TX 76374 | Oil & Gas Operator | Dec 2021 |
| 410 | K S Oil Company Inc | Norman, OK 73072-7480 | Oil & Gas Operator | May 2025 |
| 411 | Kaiser-Francis Oil Company | Tulsa, OK 74121 | Oil & Gas Operator | Jul 2025 |
| 412 | Kanokla Oil & Gas Corporation | Wellington, KS 67152-0444 | Oil & Gas Operator | Apr 2025 |
| 413 | Kato Operating Company | Bristow, OK 74010 | Oil & Gas Operator | Mar 2015 |
| 414 | KC Resources Inc | Snowmass VLG., CO 81615 | Oil & Gas Operator | Apr 2025 |
| 415 | KCS Medallion Resources, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Nov 2018 |
| 416 | Keith F. Walker Oil & Gas Co., LLC | Oklahoma City, OK 73114 | Oil & Gas Operator | May 2025 |
| 417 | Kelloil Inc | Fort Worth, TX 76116-5600 | Oil & Gas Operator | Mar 2015 |
| 418 | Ken Snyder Inc | Newalla, OK 74857-7107 | Oil & Gas Operator | Apr 2025 |
| 419 | Kennedy & Mitchell, Inc. | Houston, TX 77084 | Oil & Gas Operator | Aug 2013 |
| 420 | Kenneth W. Cory, LTD. | Bellaire, TX 77401 | Oil & Gas Operator | Apr 2025 |
| 421 | Kerr McGee Rocky MTN Corp | Denver, CO 80202-5736 | Oil & Gas Operator | Mar 2015 |
| 422 | Kerr-McGee Corporation | Dallas, TX 75380 | Oil & Gas Operator | Apr 2025 |
| 423 | Kerr-McGee Oil & Gas Onshore LLC | The Woodlands, TX 77380 | Oil & Gas Operator | Feb 2017 |
| 424 | Kerr-McGee Oil & Gas Onshore LP | Houston, TX 77046 | Oil & Gas Operator | Jul 2025 |
| 425 | Key Production Company, Inc. | Longview, TX 75606 | Oil & Gas Operator | Apr 2025 |
| 426 | Kile Production | Cypress, TX 77410 | Oil & Gas Operator | Aug 2014 |
| 427 | Kimball Production Co. | Houston, TX 77042 | Oil & Gas Operator | Jul 2002 |
| 428 | Kimbark Oil & Gas Company | Denver, CO 80203 | Oil & Gas Operator | May 2007 |
| 429 | King Operating Corporation | Fort Worth, TX 76147 | Oil & Gas Operator | Jul 2025 |
| 430 | Kingery Drilling Co., Inc. | Ardmore, OK 73402 | Oil & Gas Operator | May 2025 |
| 431 | Kirk David | Midland, TX 79705 | Oil & Gas Operator | Apr 2025 |
| 432 | Kirkpatrick Oil Company | Nichols Hill, OK 73116 | Oil & Gas Operator | Jul 2025 |
| 433 | Klo LLC | Tulsa, OK 74120-2428 | Oil & Gas Operator | May 2025 |
| 434 | KN Production Co. | Lakewood, CO 80228 | Oil & Gas Operator | Jun 2003 |
| 435 | Knutson Production Company | Loco, OK 73442-9706 | Oil & Gas Operator | Apr 2025 |
| 436 | Koch Oil Company | | Oil & Gas Operator | May 2017 |
| 437 | KRS Oil Company | Frisco, TX 75034 | Oil & Gas Operator | Apr 2020 |
| 438 | KT Energy Inc | Enid, OK 73702-2365 | Oil & Gas Operator | Apr 2025 |
| 439 | L & L Smith Energy Corporation | Muskogee, OK 74403-8479 | Oil & Gas Operator | Jan 2023 |
| 440 | L & R Energy Corporation | Spearman, TX 79081 | Oil & Gas Operator | Nov 2014 |
| 441 | Ladd Petroleum Corp. | Denver, CO 80202 | Oil & Gas Operator | Oct 2004 |
| 442 | Lamamco Drilling Company | Skiatook, OK 74070 | Oil & Gas Operator | Apr 2025 |
| 443 | Lamb Alan L | Oklahoma City, OK 73120-7824 | Oil & Gas Operator | Feb 2020 |
| 444 | Lamberton W J | Tulsa, OK 74119 | Oil & Gas Operator | Apr 2015 |
| 445 | Lammerts Robert P | Oklahoma City, OK 73102 | Oil & Gas Operator | Jan 2002 |
| 446 | Lariat Petroleum Inc | Tulsa, OK 74119 | Oil & Gas Operator | Sep 2024 |
| 447 | Larkin Energy Company Inc | Sasakwa, OK 74867 | Oil & Gas Operator | May 2022 |
| 448 | Larkspur Operating LLC | Oklahoma City, OK 73034 | Oil & Gas Operator | Apr 2025 |
| 449 | Latigo Oil And Gas Inc | Woodward, OK 73801 | Oil & Gas Operator | May 2025 |
| 450 | LCB Resources LLC | Kingfisher, OK 73750-2322 | Oil & Gas Operator | May 2025 |
| 451 | Le Norman Energy Corporation | Duncan, OK 73534 | Oil & Gas Operator | Nov 2014 |
| 452 | Leaman Oil Company | Roland, OK 74954 | Oil & Gas Operator | Apr 2014 |
| 453 | Lear Petroleum Corp | Houston, TX 77210 | Oil & Gas Operator | Mar 2015 |
| 454 | Lee Energy LLC | Edmond, OK 73034-7668 | Oil Operator | Jan 2005 |
| 455 | Legacy Reserves Operating LP | Denver, CO 80201 | Oil & Gas Operator | Jul 2025 |
| 456 | Legado Midcon, LLC | The Woodlands, TX 77380 | Oil & Gas Operator | May 2010 |
| 457 | Lime Rock Resources II-A, L.P. | Houston, TX 77002 | Oil & Gas Operator | Apr 2025 |
| 458 | Lincoln Rock Corporation | Northfield, IL 60093 | Oil & Gas Operator | Jul 2003 |
| 459 | Lindenmuth & Associates Inc | Austin, TX 78703 | Oil & Gas Operator | Aug 2024 |
| 460 | Link Oil Company (The) | Tulsa, OK 74103-4113 | Oil & Gas Operator | Jan 2014 |
| 461 | Littrell Chemical Inc | Cleo Springs, OK 73729 | Oil & Gas Operator | Jan 2005 |
| 462 | Lobo Exploration Company | Yukon, OK 73099 | Oil & Gas Operator | Apr 2025 |
| 463 | Locin Oil Corporation | Katy, TX 77494 | Oil & Gas Operator | Jul 2025 |
| 464 | Lorentz Oil & Gas LLC | Edmond, OK 73034-7266 | Oil & Gas Operator | Apr 2025 |
| 465 | Lowry Exploration Inc | Tulsa, OK 74119 | Oil & Gas Operator | Apr 2025 |
| 466 | LX4, LLC | Laverne, OK 73848 | Oil Operator | May 2025 |
| 467 | M E Klein & Associates LLC | Washington, OK 73093-4663 | Oil & Gas Operator | May 2025 |
| 468 | M M Energy, Inc. | Oklahoma City, OK 73156 | Oil & Gas Operator | Apr 2025 |
| 469 | M M Resources, Inc. | Oklahoma City, OK 73156 | Oil & Gas Operator | Sep 2018 |
| 470 | M. M. & M. Resources, Inc. | Wetumka, OK 74883 | Oil & Gas Operator | Apr 2020 |
| 471 | Maguire Oil Company | Dallas, TX 75270 | Oil & Gas Operator | Mar 2015 |
| 472 | Mahan, Janet L | | Oil & Gas Operator | Apr 2025 |
| 473 | Malson Oil Company | Crawford, OK 73638 | Oil & Gas Operator | Dec 2016 |
| 474 | Manuel Corporation | Wichita, KS 67206 | Oil & Gas Operator | May 2025 |
| 475 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | May 2025 |
| 476 | Marjo Operating Mid-Continent LLC | Tulsa, OK 74103 | Oil & Gas Operator | May 2025 |
| 477 | Marlin Oil Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Apr 2025 |
| 478 | Marmik Oil Company | El Dorado, AR 71730 | Oil & Gas Operator | Jan 2015 |
| 479 | Martin'S Resources LLC | Woodward, OK 73801-5641 | Oil & Gas Operator | Apr 2025 |
| 480 | Mathews & Casselman Oil Inc | Morris, OK 74445 | Oil & Gas Operator | Dec 2021 |
| 481 | Maverick Brothers Resources LLC | Enid, OK 73701 | Oil & Gas Operator | Apr 2025 |
| 482 | MBR Resources, Inc. | Tulsa, OK 74119 | Oil & Gas Operator | Jul 2025 |
| 483 | McCoy Petroleum Corporation | Wichita, KS 67207 | Oil & Gas Operator | Jun 2025 |
| 484 | McGee, Tom Corporation | Booker, TX 79005 | Oil & Gas Operator | Apr 2025 |
| 485 | McIntyre M L | Oklahoma City, OK 73154-0523 | Oil & Gas Operator | Jul 1996 |
| 486 | McNic Oil & Gas Midcontinent | Oklahoma City, OK 73154-0526 | Oil & Gas Operator | May 2024 |
| 487 | McO Resources Integrated Corp | Houston, TX 77057 | Oil Operator | Jan 1997 |
| 488 | Medallion Petroleum, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2015 |
| 489 | Medicine Bow Operating Company | Houston, TX 77002 | Oil & Gas Operator | Apr 2014 |
| 490 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Jul 2025 |
| 491 | Mesa Operating LP | Irving, TX 75039-3746 | Oil & Gas Operator | Oct 2010 |
| 492 | Metzner, Norma J. Estate | Wichita Falls, TX 76307 | Oil & Gas Operator | Oct 1998 |
| 493 | Mewbourne Marketing, Inc. | | Oil & Gas Operator | Mar 2013 |
| 494 | Mewbourne Oil Company | Tyler, TX 75711 | Oil & Gas Operator | Jul 2025 |
| 495 | Mge Resources, Inc. | Perryton, TX 79070 | Oil & Gas Operator | Apr 2025 |
| 496 | Mid Center Oil Company | | Oil & Gas Operator | Mar 2014 |
| 497 | Mid-Con Central Expl Co | Tulsa, OK 74136 | Oil & Gas Operator | Aug 2014 |
| 498 | Mid-Continent Energy Operating Company | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2025 |
| 499 | Middle Bay Production Co. Inc. | Houston, TX 77010 | Oil & Gas Operator | Sep 2014 |
| 500 | Midgard Energy Company | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2014 |