| 401 | Horizon Natural Resources, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Jan 2019 |
| 402 | HPC Incorporated | Denver, CO 80202 | Oil & Gas Operator | Nov 1998 |
| 403 | Hsumy Oil & Gas Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2007 |
| 404 | Hughes Gas Systems LLC | Dallas, TX 75214 | Oil & Gas Operator | Jan 2025 |
| 405 | Hugoton Energy Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Dec 2019 |
| 406 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Apr 2025 |
| 407 | Hunt, H L | Dallas, TX 75202-2785 | Oil & Gas Operator | Feb 2020 |
| 408 | Huntington Energy LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | Apr 2025 |
| 409 | Hux Oil Company LLC | Kingfisher, OK 73750 | Oil & Gas Operator | Jan 2025 |
| 410 | Impact Energy Operating LLC | Oklahoma City, OK 73172 | Oil & Gas Operator | Feb 2025 |
| 411 | Indian Oil Company | Gainesville, TX 76241 | Oil & Gas Operator | Apr 2025 |
| 412 | Infinity Hydrocarbons LLC | Houston, TX 77079 | Oil & Gas Operator | Aug 2022 |
| 413 | Investors Resources Corp | Edmond, OK 73034 | Oil & Gas Operator | Feb 2025 |
| 414 | Iron Sights Operating Inc | Stillwater, OK 74076 | Oil & Gas Operator | Jul 2022 |
| 415 | Jackson Petroleum Consult Inc | Dallas, TX 75287 | Oil & Gas Operator | Aug 1994 |
| 416 | January Investments LLC | Norman, OK 73069-8224 | Oil & Gas Operator | Feb 2025 |
| 417 | Jay Management Company LLC | Houston, TX 77057 | Oil & Gas Operator | Apr 2025 |
| 418 | Jay Petroleum Inc | Oklahoma City, OK 73154-0526 | Oil & Gas Operator | Mar 2019 |
| 419 | JB Petroleum Corporation | Purcell, OK 73080-6954 | Oil & Gas Operator | Sep 2018 |
| 420 | Jec Operating LLC | Oklahoma City, OK 73114-2717 | Oil & Gas Operator | Jan 2025 |
| 421 | JKB Resources LLC | Stigler, OK 74462 | Oil & Gas Operator | Jan 2025 |
| 422 | Jma Energy Company LLC | Oklahoma City, OK 73118 | Oil & Gas Operator | Feb 2025 |
| 423 | JN Production LLP | Guthrie, OK 73028 | Oil & Gas Operator | Jan 2025 |
| 424 | Johnson Exploration Company | Oklahoma City, OK 73102-7008 | Oil & Gas Operator | Jun 2015 |
| 425 | Jones & Pellow Oil Co | Oklahoma City, OK 73118-1115 | Oil & Gas Operator | Feb 2015 |
| 426 | Jones Energy LLC | Oklahoma City, OK 73134 | Oil & Gas Operator | Jan 2025 |
| 427 | Justiss Oil Company, Inc. | Jena, LA 71342 | Oil & Gas Operator | Jan 2025 |
| 428 | K & M Oil Company LLC | Hennessey, OK 73742 | Oil & Gas Operator | Jan 2025 |
| 429 | K M Gas Company | Oklahoma City, OK 73125 | Oil & Gas Operator | Dec 2014 |
| 430 | K S Oil Company Inc | Norman, OK 73072-7480 | Oil & Gas Operator | Feb 2025 |
| 431 | Kaiser-Francis Oil Company | Tulsa, OK 74121 | Oil & Gas Operator | Apr 2025 |
| 432 | Kaneb Operating Company | Dallas, TX 75265-0283 | Oil & Gas Operator | Dec 1995 |
| 433 | KC Resources Inc | Snowmass VLG., CO 81615 | Oil & Gas Operator | Jan 2025 |
| 434 | KCS Medallion Resources, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Nov 2018 |
| 435 | Keener Energy Company | Tulsa, OK 74103-4043 | Oil & Gas Operator | Jan 2014 |
| 436 | Kelley Oil & Gas | McAlester, OK 74570 | Oil & Gas Operator | May 2013 |
| 437 | Kepco Operating, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Dec 2024 |
| 438 | Kepco. Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2015 |
| 439 | Kerr McGee Rocky MTN Corp | Denver, CO 80202-5736 | Oil & Gas Operator | Mar 2015 |
| 440 | Kerr-McGee Corporation | Dallas, TX 75380 | Oil & Gas Operator | Jan 2025 |
| 441 | Kerr-McGee Oil & Gas Onshore LLC | The Woodlands, TX 77380 | Oil & Gas Operator | Feb 2017 |
| 442 | Kerr-McGee Oil & Gas Onshore LP | Houston, TX 77046 | Oil & Gas Operator | Apr 2025 |
| 443 | Ketal Oil Producing Company | Fort Worth, TX 76102 | Gas Operator | Sep 1995 |
| 444 | Key Production Company, Inc. | Longview, TX 75606 | Oil & Gas Operator | Jan 2025 |
| 445 | Kibtec Oil & Gas Inc | Cashion, OK 73016 | Oil & Gas Operator | Aug 2024 |
| 446 | King Energy LLC | Oklahoma City, OK 73116-9044 | Oil & Gas Operator | Feb 2025 |
| 447 | Kingfisher CSG Pullr & Const Inc | Hennessey, OK 73742-0024 | Oil & Gas Operator | Apr 2014 |
| 448 | Kingfisher Resources Inc | Clinton, OK 73601 | Oil & Gas Operator | Feb 2025 |
| 449 | Kirby Exploration Co | Houston, TX 77251 | Oil & Gas Operator | Jan 2014 |
| 450 | Kirk David | Midland, TX 79705 | Oil & Gas Operator | Jan 2025 |
| 451 | Kirkpatrick Oil Company | Nichols Hill, OK 73116 | Oil & Gas Operator | Apr 2025 |
| 452 | Klingensmith Fred T Etal | Sapulpa, OK 74066 | Oil & Gas Operator | Nov 2007 |
| 453 | KNG Producers | Dumas, TX 79029 | Oil & Gas Operator | Oct 2009 |
| 454 | Koch Midstream Services Company | Wichita, KS 67201 | Oil & Gas Operator | Oct 2000 |
| 455 | Koch Oil Company | | Oil & Gas Operator | May 2017 |
| 456 | Kopco, Inc. | Caney, KS 67333 | Oil & Gas Operator | Feb 2025 |
| 457 | KPL Production Company LLC | Oklahoma City, OK 73112-4709 | Oil & Gas Operator | Feb 2017 |
| 458 | L And L Production Company | Skellytown, TX 79080 | Oil & Gas Operator | Sep 1996 |
| 459 | Ladd LLC | El Reno, OK 73036 | Oil & Gas Operator | Nov 2018 |
| 460 | Ladd Petroleum Corp. | Denver, CO 80202 | Oil & Gas Operator | Oct 2004 |
| 461 | Lagoon Water Logistics LLC | Oklahoma City, OK 73103 | Oil Operator | Jul 2024 |
| 462 | Laguna Petroleum Corporation | Houston, TX 77046 | Oil & Gas Operator | Apr 2025 |
| 463 | Lamamco Drilling Company | Skiatook, OK 74070 | Oil & Gas Operator | Jan 2025 |
| 464 | Lammerts Robert P | Oklahoma City, OK 73102 | Oil & Gas Operator | Jan 2002 |
| 465 | Lance Ruffel Oil & Gas LLC | Oklahoma City, OK 73102-5632 | Oil & Gas Operator | Feb 2025 |
| 466 | Lariat Petroleum Inc | Tulsa, OK 74119 | Oil & Gas Operator | Sep 2024 |
| 467 | Larkspur Operating LLC | Oklahoma City, OK 73034 | Oil & Gas Operator | Jan 2025 |
| 468 | Latigo Oil And Gas Inc | Woodward, OK 73801 | Oil & Gas Operator | Feb 2025 |
| 469 | LCB Resources LLC | Kingfisher, OK 73750-2322 | Oil & Gas Operator | Feb 2025 |
| 470 | Le Norman Energy Corporation | Duncan, OK 73534 | Oil & Gas Operator | Nov 2014 |
| 471 | Levinson Partners Corporation | Denver, CO 80202 | Oil & Gas Operator | Jul 1995 |
| 472 | Lime Rock Resources II-A, L.P. | Houston, TX 77002 | Oil & Gas Operator | Jan 2025 |
| 473 | Lindenmuth & Associates Inc | Austin, TX 78703 | Oil & Gas Operator | Aug 2024 |
| 474 | Linn Mid-Continent Operating Inc | Houston, TX 77002-3018 | Oil & Gas Operator | Jun 2016 |
| 475 | Lion Petroleum Company | Oklahoma City, OK 73120-4503 | Oil & Gas Operator | Aug 2015 |
| 476 | LMR Oil Company | Wichita, KS 67202 | Oil & Gas Operator | Sep 1998 |
| 477 | Locators Oil And Gas Inc | Guthrie, OK 73044 | Oil & Gas Operator | Oct 2022 |
| 478 | Lone Tree Oil & Gas LLC | Greenwood VLG, CO 80111 | Oil & Gas Operator | Apr 2025 |
| 479 | Lorentz Oil & Gas LLC | Edmond, OK 73034-7266 | Oil & Gas Operator | Jan 2025 |
| 480 | Louis Dreyfus Gas Marketing | Oklahoma City, OK 73134 | Oil & Gas Operator | Mar 2018 |
| 481 | Louisiana Land & Exploration Co. | Houston, TX 77210 | Oil & Gas Operator | Sep 2013 |
| 482 | Lu-Ray Petroleum LLC | Oklahoma City, OK 73121-1607 | Oil & Gas Operator | Feb 2025 |
| 483 | Lynx Energy Company, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Mar 2008 |
| 484 | Lynx Operating Co., Inc. | Dallas, TX 75206 | Oil & Gas Operator | Apr 2025 |
| 485 | M & S Oil Co | Lawrenceburg, IN 47025-8675-8675 | Oil & Gas Operator | Aug 2000 |
| 486 | M And V Resources Inc | Crescent, OK 73028 | Oil & Gas Operator | Jan 2025 |
| 487 | M E Klein & Associates LLC | Washington, OK 73093-4663 | Oil & Gas Operator | Feb 2025 |
| 488 | M H Oil & Gas LLC | Okeene, OK 73763-0684 | Oil & Gas Operator | Feb 2013 |
| 489 | M M Energy, Inc. | Oklahoma City, OK 73156 | Oil & Gas Operator | Jan 2025 |
| 490 | M M Resources, Inc. | Oklahoma City, OK 73156 | Oil & Gas Operator | Sep 2018 |
| 491 | M V Purchasing LLC | Wichita, KS 67202 | Oil & Gas Operator | Jan 2025 |
| 492 | M. S. Productions, Inc. | Pittsburg, KS 66762 | Oil & Gas Operator | Nov 2019 |
| 493 | Mac Laskey Kelly Oilfield | El Dorado, KS 67042 | Oil & Gas Operator | Feb 2025 |
| 494 | Mack Energy Co. | Duncan, OK 73534 | Oil & Gas Operator | Feb 2025 |
| 495 | Mackellar Inc | Oklahoma City, OK 73116-7101 | Oil & Gas Operator | Feb 2025 |
| 496 | Magnum Energy Inc | Norman, OK 73072-2403 | Oil & Gas Operator | Feb 2025 |
| 497 | Mallard Oil & Gas | Cody, WY 82414-9640 | Oil & Gas Operator | Oct 2019 |
| 498 | Malson Oil Company | Crawford, OK 73638 | Oil & Gas Operator | Dec 2016 |
| 499 | Maple Properties Corp | Dallas, TX 75204 | Oil & Gas Operator | Jan 1999 |
| 500 | Marathon Oil Company | Houston, TX 77024 | Oil & Gas Operator | Feb 2025 |