| 401 | Hugoton Energy Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Dec 2019 |
| 402 | Hull Oil Co. | Wichita Falls, TX 76308 | Oil & Gas Operator | Sep 2021 |
| 403 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Apr 2025 |
| 404 | Hunt Petroleum Corporation | Dallas, TX 75201 | Oil & Gas Operator | Nov 2008 |
| 405 | Huntington Energy LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | Apr 2025 |
| 406 | Impact Energy Operating LLC | Oklahoma City, OK 73172 | Oil & Gas Operator | Feb 2025 |
| 407 | Indian Oil Company | Gainesville, TX 76241 | Oil & Gas Operator | Apr 2025 |
| 408 | Indian Wells Oil Co | Oklahoma City, OK 73116 | Oil & Gas Operator | Jan 2000 |
| 409 | Internorth Inc | Tulsa, OK 74136 | Oil & Gas Operator | Apr 2014 |
| 410 | Iron Sights Operating Inc | Stillwater, OK 74076 | Oil & Gas Operator | Jul 2022 |
| 411 | J-Brex Company | Amarillo, TX 79101 | Oil & Gas Operator | Apr 2025 |
| 412 | J-W Operating Company | Christoval, TX 76935 | Oil & Gas Operator | Apr 2025 |
| 413 | Jackson Petroleum Consult Inc | Dallas, TX 75287 | Oil & Gas Operator | Aug 1994 |
| 414 | Jaquess W D "Bud" | Ada, OK 74820 | Oil & Gas Operator | Jan 2018 |
| 415 | JCR, Jr - Operating, Inc. | Amarillo, TX 79114 | Oil & Gas Operator | Apr 2022 |
| 416 | JCS Operating LLC | Guymon, OK 73942 | Oil & Gas Operator | Jan 2025 |
| 417 | Jebito Farm LLC | Oklahoma City, OK 73162-6249 | Oil & Gas Operator | Jan 2025 |
| 418 | Jec Operating LLC | Oklahoma City, OK 73114-2717 | Oil & Gas Operator | Jan 2025 |
| 419 | Jeron Oil And Gas Inc | Denison, TX 75020 | Oil & Gas Operator | Jun 2000 |
| 420 | Jet Oil Co12/Ofb See 18649 | | Oil & Gas Operator | Jul 2007 |
| 421 | Jetta Operating Company Inc | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2025 |
| 422 | Jim Clower Inc | Beaver, OK 73932 | Oil & Gas Operator | Jan 2025 |
| 423 | JKB Resources LLC | Stigler, OK 74462 | Oil & Gas Operator | Jan 2025 |
| 424 | JLR Investments Inc | Oklahoma City, OK 73151-9101 | Oil & Gas Operator | Sep 2014 |
| 425 | Jma Energy Company LLC | Oklahoma City, OK 73118 | Oil & Gas Operator | Feb 2025 |
| 426 | Jma Resources, Inc. | Oklahoma City, OK 73112 | Oil & Gas Operator | Jan 2025 |
| 427 | JN Exploration & Production LP | Billings, MT 59103 | Oil & Gas Operator | Jan 2001 |
| 428 | JN Production LLP | Guthrie, OK 73028 | Oil & Gas Operator | Jan 2025 |
| 429 | Jo-Allyn Oil Co Inc | Laverne, OK 73848 | Oil & Gas Operator | Feb 2025 |
| 430 | Johnson E Lyle | Oklahoma City, OK 73142 | Oil & Gas Operator | Jan 2025 |
| 431 | Johnson Exploration Company | Oklahoma City, OK 73102-7008 | Oil & Gas Operator | Jun 2015 |
| 432 | Jolen Operating Company | Oklahoma City, OK 73102 | Oil & Gas Operator | Jan 2025 |
| 433 | Jones Oil Company LLC (The) | Duncan, OK 73533-4995 | Oil & Gas Operator | Jan 2025 |
| 434 | JW Exploration LLC Of Texas | Dallas, TX 75287-3329 | Oil & Gas Operator | Jun 2017 |
| 435 | K & F Oil Co. | Olney, TX 76374 | Oil & Gas Operator | Dec 2021 |
| 436 | K M Gas Company | Oklahoma City, OK 73125 | Oil & Gas Operator | Dec 2014 |
| 437 | K S Oil Company Inc | Norman, OK 73072-7480 | Oil & Gas Operator | Feb 2025 |
| 438 | Kaiser-Francis Oil Company | Tulsa, OK 74121 | Oil & Gas Operator | Apr 2025 |
| 439 | Kanokla Oil & Gas Corporation | Wellington, KS 67152-0444 | Oil & Gas Operator | Jan 2025 |
| 440 | Kato Operating Company | Bristow, OK 74010 | Oil & Gas Operator | Mar 2015 |
| 441 | KC Resources Inc | Snowmass VLG., CO 81615 | Oil & Gas Operator | Jan 2025 |
| 442 | KCS Medallion Resources, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Nov 2018 |
| 443 | Keener Energy Company | Tulsa, OK 74103-4043 | Oil & Gas Operator | Jan 2014 |
| 444 | Keith F. Walker Oil & Gas Co., LLC | Oklahoma City, OK 73114 | Oil & Gas Operator | Feb 2025 |
| 445 | Kelloil Inc | Fort Worth, TX 76116-5600 | Oil & Gas Operator | Mar 2015 |
| 446 | Ken Snyder Inc | Newalla, OK 74857-7107 | Oil & Gas Operator | Jan 2025 |
| 447 | Kennedy & Mitchell, Inc. | Houston, TX 77084 | Oil & Gas Operator | Aug 2013 |
| 448 | Kenneth W. Cory, LTD. | Bellaire, TX 77401 | Oil & Gas Operator | Jan 2025 |
| 449 | Kerr McGee Rocky MTN Corp | Denver, CO 80202-5736 | Oil & Gas Operator | Mar 2015 |
| 450 | Kerr-McGee Corporation | Dallas, TX 75380 | Oil & Gas Operator | Jan 2025 |
| 451 | Kerr-McGee Oil & Gas Onshore LLC | The Woodlands, TX 77380 | Oil & Gas Operator | Feb 2017 |
| 452 | Kerr-McGee Oil & Gas Onshore LP | Houston, TX 77046 | Oil & Gas Operator | Apr 2025 |
| 453 | Key Production Company, Inc. | Longview, TX 75606 | Oil & Gas Operator | Jan 2025 |
| 454 | Kile Production | Cypress, TX 77410 | Oil & Gas Operator | Aug 2014 |
| 455 | Kimball Production Co. | Houston, TX 77042 | Oil & Gas Operator | Jul 2002 |
| 456 | Kimbark Oil & Gas Company | Denver, CO 80203 | Oil & Gas Operator | May 2007 |
| 457 | King Operating Corporation | Fort Worth, TX 76147 | Oil & Gas Operator | Apr 2025 |
| 458 | Kingery Drilling Co., Inc. | Ardmore, OK 73402 | Oil & Gas Operator | Jan 2025 |
| 459 | Kiowa Gas Company | Dallas, TX 75206 | Oil & Gas Operator | Dec 2024 |
| 460 | Kirk David | Midland, TX 79705 | Oil & Gas Operator | Jan 2025 |
| 461 | Kirkpatrick Oil Company | Nichols Hill, OK 73116 | Oil & Gas Operator | Apr 2025 |
| 462 | Klingensmith Fred T Etal | Sapulpa, OK 74066 | Oil & Gas Operator | Nov 2007 |
| 463 | Klo LLC | Tulsa, OK 74120-2428 | Oil & Gas Operator | Feb 2025 |
| 464 | KN Production Co. | Lakewood, CO 80228 | Oil & Gas Operator | Jun 2003 |
| 465 | Knutson Production Company | Loco, OK 73442-9706 | Oil & Gas Operator | Feb 2025 |
| 466 | Koch Oil Company | | Oil & Gas Operator | May 2017 |
| 467 | KRS Oil Company | Frisco, TX 75034 | Oil & Gas Operator | Apr 2020 |
| 468 | KT Energy Inc | Enid, OK 73702-2365 | Oil & Gas Operator | Jan 2025 |
| 469 | L & L Smith Energy Corporation | Muskogee, OK 74403-8479 | Oil & Gas Operator | Jan 2023 |
| 470 | L & R Energy Corporation | Spearman, TX 79081 | Oil & Gas Operator | Nov 2014 |
| 471 | Ladd Petroleum Corp. | Denver, CO 80202 | Oil & Gas Operator | Oct 2004 |
| 472 | Lamamco Drilling Company | Skiatook, OK 74070 | Oil & Gas Operator | Jan 2025 |
| 473 | Lamb Alan L | Oklahoma City, OK 73120-7824 | Oil & Gas Operator | Feb 2020 |
| 474 | Lamberton W J | Tulsa, OK 74119 | Oil & Gas Operator | Apr 2015 |
| 475 | Lammerts Robert P | Oklahoma City, OK 73102 | Oil & Gas Operator | Jan 2002 |
| 476 | Lariat Petroleum Inc | Tulsa, OK 74119 | Oil & Gas Operator | Sep 2024 |
| 477 | Larkin Energy Company Inc | Sasakwa, OK 74867 | Oil & Gas Operator | May 2022 |
| 478 | Larkspur Operating LLC | Oklahoma City, OK 73034 | Oil & Gas Operator | Jan 2025 |
| 479 | Latigo Oil And Gas Inc | Woodward, OK 73801 | Oil & Gas Operator | Feb 2025 |
| 480 | LCB Resources LLC | Kingfisher, OK 73750-2322 | Oil & Gas Operator | Feb 2025 |
| 481 | Le Norman Energy Corporation | Duncan, OK 73534 | Oil & Gas Operator | Nov 2014 |
| 482 | Leaman Oil Company | Roland, OK 74954 | Oil & Gas Operator | Apr 2014 |
| 483 | Lear Petroleum Corp | Houston, TX 77210 | Oil & Gas Operator | Mar 2015 |
| 484 | Lee Energy LLC | Edmond, OK 73034-7668 | Oil Operator | Jan 2005 |
| 485 | Legacy Reserves Operating LP | Denver, CO 80201 | Oil & Gas Operator | Apr 2025 |
| 486 | Legado Midcon, LLC | The Woodlands, TX 77380 | Oil & Gas Operator | May 2010 |
| 487 | Lime Rock Resources II-A, L.P. | Houston, TX 77002 | Oil & Gas Operator | Jan 2025 |
| 488 | Lincoln Rock Corporation | Northfield, IL 60093 | Oil & Gas Operator | Jul 2003 |
| 489 | Lindenmuth & Associates Inc | Austin, TX 78703 | Oil & Gas Operator | Aug 2024 |
| 490 | Link Oil Company (The) | Tulsa, OK 74103-4113 | Oil & Gas Operator | Jan 2014 |
| 491 | Littrell Chemical Inc | Cleo Springs, OK 73729 | Oil & Gas Operator | Jan 2005 |
| 492 | Lobo Exploration Company | Yukon, OK 73099 | Oil & Gas Operator | Jan 2025 |
| 493 | Locin Oil Corporation | Houston, TX 77002 | Oil & Gas Operator | Apr 2025 |
| 494 | Lorentz Oil & Gas LLC | Edmond, OK 73034-7266 | Oil & Gas Operator | Jan 2025 |
| 495 | Lowry Exploration Inc | Tulsa, OK 74119 | Oil & Gas Operator | Jan 2025 |
| 496 | LX4 LLC | Gage, OK 73843 | Oil Operator | Dec 2024 |
| 497 | M C L Company LTD | Edmond, OK 73083-6243 | Oil & Gas Operator | Jul 2001 |
| 498 | M E Klein & Associates LLC | Washington, OK 73093-4663 | Oil & Gas Operator | Feb 2025 |
| 499 | M M & M Resources Inc | Wetumka, OK 74883 | Oil & Gas Operator | Apr 2020 |
| 500 | M M Energy, Inc. | Oklahoma City, OK 73156 | Oil & Gas Operator | Jan 2025 |