| 401 | Kerr-McGee Refining Corp | Oklahoma City, OK 73125 | Oil & Gas Operator | Jun 2007 |
| 402 | Key Production Company, Inc. | Longview, TX 75606 | Oil & Gas Operator | Mar 2025 |
| 403 | Kingery Drilling Co., Inc. | Ardmore, OK 73402 | Oil & Gas Operator | Mar 2025 |
| 404 | Kingfisher Resources Inc | Clinton, OK 73601 | Oil & Gas Operator | Mar 2025 |
| 405 | Kirkpatrick Oil Company | Nichols Hill, OK 73116 | Oil & Gas Operator | May 2025 |
| 406 | KLBW Partners LLC | Ratliff City, OK 73481 | Oil & Gas Operator | Feb 2025 |
| 407 | Klo LLC | Tulsa, OK 74120-2428 | Oil & Gas Operator | Mar 2025 |
| 408 | KNG Producers | Dumas, TX 79029 | Oil & Gas Operator | Oct 2009 |
| 409 | Koch Oil Company | | Oil & Gas Operator | May 2017 |
| 410 | Kolar Petroleum Inc | Oklahoma City, OK 73162-1509 | Oil & Gas Operator | Jun 2007 |
| 411 | KRS Oil Company | Frisco, TX 75034 | Oil & Gas Operator | Apr 2020 |
| 412 | KT Energy Inc | Enid, OK 73702-2365 | Oil & Gas Operator | Feb 2025 |
| 413 | Kybenco Disposals LLC | Maysville, OK 73052 | Oil Operator | Sep 2022 |
| 414 | L E Jones Operating Inc | Duncan, OK 73534 | Oil & Gas Operator | Mar 2025 |
| 415 | Ladd Petroleum Corp. | Denver, CO 80202 | Oil & Gas Operator | Oct 2004 |
| 416 | Lamamco Drilling Company | Skiatook, OK 74070 | Oil & Gas Operator | Feb 2025 |
| 417 | Lance Ruffel Oil & Gas LLC | Oklahoma City, OK 73102-5632 | Oil & Gas Operator | Mar 2025 |
| 418 | Laran Operating LLC | Dover, OK 73734-0057 | Oil & Gas Operator | Mar 2015 |
| 419 | Laredo Petroleum Inc | Tulsa, OK 74120 | Oil & Gas Operator | Mar 2023 |
| 420 | Lariat Energy & Supply Co Inc | Hulbert, OK 74441 | Oil & Gas Operator | Mar 2025 |
| 421 | Lariat Petroleum Inc | Tulsa, OK 74119 | Oil & Gas Operator | Sep 2024 |
| 422 | Larson Operating Company | Olmitz, KS 67564-8561 | Oil & Gas Operator | Dec 2019 |
| 423 | Latigo Drilling Corporation | Duncan, OK 73533 | Oil & Gas Operator | Mar 2025 |
| 424 | Latigo Oil And Gas Inc | Woodward, OK 73801 | Oil & Gas Operator | Mar 2025 |
| 425 | Laurco Energies,Inc | | Oil & Gas Operator | Oct 2024 |
| 426 | Laurel Operating Company, Inc. | Stillwater, OK 74074-3025 | Oil & Gas Operator | Mar 2025 |
| 427 | LCB Resources LLC | Kingfisher, OK 73750-2322 | Oil & Gas Operator | Mar 2025 |
| 428 | Le Bas Operating Company, Inc. | Giddings, TX 78942 | Oil & Gas Operator | Mar 2000 |
| 429 | Le Norman Energy Corporation | Duncan, OK 73534 | Oil & Gas Operator | Nov 2014 |
| 430 | Leavell Resources Corporation | Hays, KS 67601 | Oil & Gas Operator | Mar 2015 |
| 431 | Legacy Reserves Operating LP | Denver, CO 80201 | Oil & Gas Operator | May 2025 |
| 432 | Lewis J K | Duncan, OK 73534-1742 | Oil & Gas Operator | Apr 2015 |
| 433 | Lewis Oil Operations LLC | Ratliff City, OK 73481 | Oil & Gas Operator | Feb 2025 |
| 434 | Lillard Pipe & Supply Inc | Shawnee, OK 74802-0847 | Oil & Gas Operator | Nov 2014 |
| 435 | Lime Rock Resources A, L.P. | Houston, TX 77002 | Oil & Gas Operator | Feb 2025 |
| 436 | Lime Rock Resources II-A, L.P. | Houston, TX 77002 | Oil & Gas Operator | Feb 2025 |
| 437 | Lime Rock Resources III-A, L.P. | Houston, TX 77002 | Oil & Gas Operator | Mar 2025 |
| 438 | Linam Harry Dba Sooner State Production | Marlow, OK 73055-0583 | Oil & Gas Operator | Apr 2015 |
| 439 | Lindenmuth & Associates Inc | Austin, TX 78703 | Oil & Gas Operator | Aug 2024 |
| 440 | Locators Oil And Gas Inc | Guthrie, OK 73044 | Oil & Gas Operator | Oct 2022 |
| 441 | Loman Linda Gann | Norman, OK 73069-6548 | Oil Operator | Apr 2011 |
| 442 | Lone Tree Oil & Gas LLC | Greenwood VLG, CO 80111 | Oil & Gas Operator | May 2025 |
| 443 | Longacre Oil & Gas | Enid, OK 73702 | Oil & Gas Operator | Mar 2013 |
| 444 | Lorentz Oil & Gas LLC | Edmond, OK 73034-7266 | Oil & Gas Operator | Feb 2025 |
| 445 | Loto Energy LLC | Saint Louis, MO 63105 | Oil & Gas Operator | Feb 2025 |
| 446 | Louisiana Land & Exploration Co. | Houston, TX 77210 | Oil & Gas Operator | Sep 2013 |
| 447 | LX4, LLC | | Oil Operator | Mar 2025 |
| 448 | M E Klein & Associates LLC | Washington, OK 73093-4663 | Oil & Gas Operator | Mar 2025 |
| 449 | Mack Energy Co. | Duncan, OK 73534 | Oil & Gas Operator | Mar 2025 |
| 450 | Mack Oil Company | Duncan, OK 73534 | Oil & Gas Operator | Nov 2000 |
| 451 | Mackellar Inc | Oklahoma City, OK 73116-7101 | Oil & Gas Operator | Mar 2025 |
| 452 | Magnum Energy Inc | Norman, OK 73072-2403 | Oil & Gas Operator | Mar 2025 |
| 453 | Mallorn Energy LLC | Edmond, OK 73034 | Oil & Gas Operator | Feb 2025 |
| 454 | Maly & Maly Oil | Beggs, OK 74421-2844 | Oil & Gas Operator | Jan 2025 |
| 455 | Manuel Corporation | Wichita, KS 67206 | Oil & Gas Operator | Mar 2025 |
| 456 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Mar 2025 |
| 457 | Markley L C Corporation | Fletcher, OK 73541 | Oil & Gas Operator | Aug 2002 |
| 458 | Marlin Oil Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Feb 2025 |
| 459 | Marshall Oil Corporation | Oklahoma City, OK 73154 | Oil & Gas Operator | Apr 2017 |
| 460 | Maverick Brothers Resources LLC | Enid, OK 73701 | Oil & Gas Operator | Feb 2025 |
| 461 | Maxine Oil Company | Muskogee, OK 74401-0512 | Oil & Gas Operator | Sep 2014 |
| 462 | MBR Resources, Inc. | Tulsa, OK 74119 | Oil & Gas Operator | May 2025 |
| 463 | McClintock V C | Casper, WY 82601 | Oil & Gas Operator | May 2024 |
| 464 | McCord J K | Duncan, OK 73534-0032 | Oil Operator | Mar 2009 |
| 465 | McQueen Ed & Company Inc | Lindsey, OK 73052 | Oil & Gas Operator | Apr 2014 |
| 466 | Meade Energy Corporation | Oklahoma City, OK 73118-4015 | Oil & Gas Operator | Mar 2025 |
| 467 | Meadowbrook Oil Corporation Of Ok Inc | Del City, OK 73115-3608 | Oil & Gas Operator | Mar 2025 |
| 468 | Medallion Petroleum, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2015 |
| 469 | Mep Operating LLC | Houston, TX 77056-2733 | Oil & Gas Operator | Mar 2025 |
| 470 | Meridian Exploration Inc | Oklahoma City, OK 73128 | Oil & Gas Operator | Aug 2013 |
| 471 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | May 2025 |
| 472 | Mesa Operating LP | Irving, TX 75039-3746 | Oil & Gas Operator | Oct 2010 |
| 473 | Mewbourne Oil Company | Tyler, TX 75711 | Oil & Gas Operator | May 2025 |
| 474 | Mge Resources, Inc. | Perryton, TX 79070 | Oil & Gas Operator | Feb 2025 |
| 475 | MGF Oil Corporation | Tulsa, OK 74121 | Oil & Gas Operator | Jun 1998 |
| 476 | Mid-Con Central Expl Co | Tulsa, OK 74136 | Oil & Gas Operator | Aug 2014 |
| 477 | Mid-Con Energy Operating, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | May 2020 |
| 478 | Mid-Con Energy Operating, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Apr 2025 |
| 479 | Mid-Continent Petroleum Management Inc | Cement, OK 73017 | Oil & Gas Operator | Mar 2025 |
| 480 | Midwest Enterprises, Inc. | Cashion, OK 73016-9626 | Oil & Gas Operator | Jan 2025 |
| 481 | Mija LLC | Oklahoma City, OK 73151 | Oil & Gas Operator | Mar 2025 |
| 482 | Mild Oil Company | Duncan, OK 73533-9532 | Oil Operator | Mar 2000 |
| 483 | Minerva Oil Company | Tulsa, OK 74152-0858 | Oil & Gas Operator | Mar 2015 |
| 484 | Mink Oil Company | | Oil Operator | Nov 2003 |
| 485 | Mink Richard | Cement, OK 73017 | Oil & Gas Operator | Feb 2025 |
| 486 | Mobil Exp & Prod Us Inc | Houston, TX 77060-1991 | Oil & Gas Operator | May 2001 |
| 487 | Monexco Operating Company | Dallas, TX 75204-2634 | Oil & Gas Operator | Feb 2025 |
| 488 | Monroe Natural Gas Inc | Norman, OK 73071 | Oil & Gas Operator | Feb 2025 |
| 489 | Montgomery Exploration Co LTD | Dallas, TX 75204-2634 | Oil & Gas Operator | Mar 2025 |
| 490 | Monty L Hott Production Corporation | Oklahoma City, OK 73142 | Oil & Gas Operator | Feb 2025 |
| 491 | Moore & Moore Energy Inc | Purcell, OK 73080-0674 | Oil & Gas Operator | Dec 2012 |
| 492 | Moore David K | Duncan, OK 73575 | Oil & Gas Operator | Oct 2009 |
| 493 | Mott Oil & Gas | Sugarland, TX 77478 | Oil & Gas Operator | May 2001 |
| 494 | Mott Petroleum Corporation | Sugar Land, TX 77487 | Oil & Gas Operator | Aug 2024 |
| 495 | Muirfield Resources Company | Tulsa, OK 74101-3166 | Oil & Gas Operator | Jun 2024 |
| 496 | Mustang Fuel Corp. Of Oklahoma | Oklahoma City, OK 73106 | Oil & Gas Operator | Nov 2016 |
| 497 | Mustang Fuel Corporation | Oklahoma City, OK 73114 | Oil & Gas Operator | Mar 2025 |
| 498 | Mustang Gas Products LLC | Oklahoma City, OK 73114-7406 | Oil & Gas Operator | Sep 2022 |
| 499 | MW Petroleum Corporation | Houston, TX 77056 | Oil & Gas Operator | Mar 2015 |
| 500 | National Cooperative RFG Assoc | McPherson, KS 67460-1404 | Oil & Gas Operator | Jun 2006 |