| 301 | K & F Oil Co. | Olney, TX 76374 | Oil & Gas Operator | Dec 2021 |
| 302 | K Energy Inc | Mannford, OK 74044-3023 | Oil & Gas Operator | May 2013 |
| 303 | K O G Production LLC | Freedom, OK 73842 | Oil & Gas Operator | May 2025 |
| 304 | K S Oil Company Inc | Norman, OK 73072-7480 | Oil & Gas Operator | May 2025 |
| 305 | Kaiser-Francis Oil Company | Tulsa, OK 74121 | Oil & Gas Operator | Jul 2025 |
| 306 | Kanokla Oil & Gas Corporation | Wellington, KS 67152-0444 | Oil & Gas Operator | Apr 2025 |
| 307 | Katsco Energy, Inc. | Round Rock, TX 78664 | Oil & Gas Operator | Jul 2025 |
| 308 | KC Resources Inc | Snowmass VLG., CO 81615 | Oil & Gas Operator | Apr 2025 |
| 309 | KCS Medallion Resources, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Nov 2018 |
| 310 | Kelt Oil & Gas | Houston, TX 77060 | Oil & Gas Operator | Dec 1998 |
| 311 | Kennedy & Mitchell, Inc. | Houston, TX 77084 | Oil & Gas Operator | Aug 2013 |
| 312 | Kerr McGee Rocky MTN Corp | Denver, CO 80202-5736 | Oil & Gas Operator | Mar 2015 |
| 313 | Kerr-McGee Corporation | Dallas, TX 75380 | Oil & Gas Operator | Apr 2025 |
| 314 | Kerr-McGee Oil & Gas Onshore LP | Houston, TX 77046 | Oil & Gas Operator | Jul 2025 |
| 315 | Key Production Company, Inc. | Longview, TX 75606 | Oil & Gas Operator | Apr 2025 |
| 316 | Kingery Drilling Co., Inc. | Ardmore, OK 73402 | Oil & Gas Operator | May 2025 |
| 317 | Kingfisher CSG Pullr & Const Inc | Hennessey, OK 73742-0024 | Oil & Gas Operator | Apr 2014 |
| 318 | Kirkpatrick Oil Company | Nichols Hill, OK 73116 | Oil & Gas Operator | Jul 2025 |
| 319 | Klo LLC | Tulsa, OK 74120-2428 | Oil & Gas Operator | May 2025 |
| 320 | KNG Producers | Dumas, TX 79029 | Oil & Gas Operator | Oct 2009 |
| 321 | Koch Oil Company | | Oil & Gas Operator | May 2017 |
| 322 | Kolibri Energy Us, Inc. | Thousand Oaks, CA 91320-1272 | Oil & Gas Operator | Apr 2025 |
| 323 | KT Energy Inc | Enid, OK 73702-2365 | Oil & Gas Operator | Apr 2025 |
| 324 | L & L Smith Energy Corporation | Muskogee, OK 74403-8479 | Oil & Gas Operator | Jan 2023 |
| 325 | Lake Ronel Oil Company | Tyler, TX 75710 | Oil & Gas Operator | Jul 2017 |
| 326 | Lamamco Drilling Company | Skiatook, OK 74070 | Oil & Gas Operator | Apr 2025 |
| 327 | Lariat Energy & Supply Co Inc | Hulbert, OK 74441 | Oil & Gas Operator | Apr 2025 |
| 328 | Lariat Petroleum Inc | Tulsa, OK 74119 | Oil & Gas Operator | Sep 2024 |
| 329 | Larson Operating Company | Olmitz, KS 67564-8561 | Oil & Gas Operator | Dec 2019 |
| 330 | Latigo Oil And Gas Inc | Woodward, OK 73801 | Oil & Gas Operator | May 2025 |
| 331 | LCB Resources LLC | Kingfisher, OK 73750-2322 | Oil & Gas Operator | May 2025 |
| 332 | Le Norman Energy Corporation | Duncan, OK 73534 | Oil & Gas Operator | Nov 2014 |
| 333 | Leede Oil & Gas Inc. | Greenwood VLG, CO 80111 | Oil & Gas Operator | Aug 2003 |
| 334 | Legacy Reserves Operating LP | Denver, CO 80201 | Oil & Gas Operator | Jul 2025 |
| 335 | Lime Rock Resources II-A, L.P. | Houston, TX 77002 | Oil & Gas Operator | Apr 2025 |
| 336 | Lindenmuth & Associates Inc | Austin, TX 78703 | Oil & Gas Operator | Aug 2024 |
| 337 | Litzenberger Exploration | Waynoka, OK 73860 | Oil & Gas Operator | Jul 1996 |
| 338 | Litzenberger Exploration Inc | Waynoka, OK 73860 | Oil & Gas Operator | May 2025 |
| 339 | Lobo Exploration Company | Yukon, OK 73099 | Oil & Gas Operator | Apr 2025 |
| 340 | Long Engineering Company Inc | Oklahoma City, OK 73112-7769 | Oil Operator | Jun 2008 |
| 341 | Luke Oil Company | Bristow, OK 74010 | Oil & Gas Operator | Apr 2025 |
| 342 | M & M Exploration, Inc. | Westminster, CO 80031 | Oil & Gas Operator | May 2025 |
| 343 | M H Oil & Gas LLC | Okeene, OK 73763-0684 | Oil & Gas Operator | Feb 2013 |
| 344 | M M Energy, Inc. | Oklahoma City, OK 73156 | Oil & Gas Operator | Apr 2025 |
| 345 | M M Resources, Inc. | Oklahoma City, OK 73156 | Oil & Gas Operator | Sep 2018 |
| 346 | Mack Energy Co. | Duncan, OK 73534 | Oil & Gas Operator | May 2025 |
| 347 | Mack Oil Company | Duncan, OK 73534 | Oil & Gas Operator | Nov 2000 |
| 348 | Magic Investments LLC | Edmond, OK 73013 | Oil & Gas Operator | Jan 2025 |
| 349 | Maguire James Q Inc | Norman, OK 73070-1748 | Oil & Gas Operator | Jun 2011 |
| 350 | Majors Eugene E | Holdenville, OK 74848-9603 | Oil & Gas Operator | Apr 2025 |
| 351 | Malka Production Company | Oklahoma City, OK 73101-0248 | Oil & Gas Operator | Jan 2000 |
| 352 | Malson Oil Company | Crawford, OK 73638 | Oil & Gas Operator | Dec 2016 |
| 353 | Manuel Corporation | Wichita, KS 67206 | Oil & Gas Operator | May 2025 |
| 354 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | May 2025 |
| 355 | Marbet LLC | Edmond, OK 73013-6691 | Oil & Gas Operator | Apr 2025 |
| 356 | Marjo Operating Mid-Continent LLC | Tulsa, OK 74103 | Oil & Gas Operator | May 2025 |
| 357 | Mark L Shidler Inc | Houston, TX 77055 | Oil & Gas Operator | May 2025 |
| 358 | Marlin Oil Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Apr 2025 |
| 359 | Marshall Oil Corporation | Oklahoma City, OK 73154 | Oil & Gas Operator | Apr 2017 |
| 360 | Matador E & P Company Inc | | Oil & Gas Operator | May 2020 |
| 361 | Mator LLC | Hennessey, OK 73742-1235 | Oil & Gas Operator | May 2025 |
| 362 | Maverick Brothers Resources LLC | Enid, OK 73701 | Oil & Gas Operator | Apr 2025 |
| 363 | McCoy Petroleum Corporation | Wichita, KS 67207 | Oil & Gas Operator | Jun 2025 |
| 364 | McGee, Tom Corporation | Booker, TX 79005 | Oil & Gas Operator | Apr 2025 |
| 365 | McGinness Energy Company Inc | Wichita, KS 67206 | Oil & Gas Operator | Apr 2025 |
| 366 | Meade Energy Corporation | Oklahoma City, OK 73118-4015 | Oil & Gas Operator | May 2025 |
| 367 | Meadowbrook Oil Corporation Of Ok Inc | Del City, OK 73115-3608 | Oil & Gas Operator | May 2025 |
| 368 | Medicine Bow Operating Company | Houston, TX 77002 | Oil & Gas Operator | Apr 2014 |
| 369 | Mendell Petroleum Corporation | Castle Rock, CO 80104-9045 | Oil & Gas Operator | Sep 2004 |
| 370 | Meridian Oil Production Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 2024 |
| 371 | Mesa Operating LP | Irving, TX 75039-3746 | Oil & Gas Operator | Oct 2010 |
| 372 | Metropolitan Resources Corp | Tulsa, OK 74169-1734 | Oil & Gas Operator | Mar 2015 |
| 373 | MGF Oil Corporation | Tulsa, OK 74121 | Oil & Gas Operator | Jun 1998 |
| 374 | Mid-Con Central Expl Co | Tulsa, OK 74136 | Oil & Gas Operator | Aug 2014 |
| 375 | Middle Bay Production Co. Inc. | Houston, TX 77010 | Oil & Gas Operator | Sep 2014 |
| 376 | Midgard Energy Company | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2014 |
| 377 | Midnight Hour LLC | Enid, OK 73702 | Oil & Gas Operator | Apr 2020 |
| 378 | Midstates Oil Company | Oklahoma City, OK 73112 | Oil & Gas Operator | Nov 2000 |
| 379 | Mija LLC | Oklahoma City, OK 73151 | Oil & Gas Operator | May 2025 |
| 380 | Miller Exploration Company | Tulsa, OK 74136-1020 | Oil & Gas Operator | Mar 2015 |
| 381 | Milmac Operating Company | Lubbock, TX 79408-2976 | Oil & Gas Operator | Sep 2004 |
| 382 | MJM Resources Inc | Norman, OK 73072 | Oil & Gas Operator | May 2025 |
| 383 | Molz Oil Company | Kiowa, KS 67070 | Oil & Gas Operator | May 2025 |
| 384 | Monterey Production Company LLC | Tulsa, OK 74136 | Oil & Gas Operator | May 2025 |
| 385 | Muras Energy Inc | Edmond, OK 73013 | Oil & Gas Operator | Apr 2025 |
| 386 | Mustang Fuel Corp. Of Oklahoma | Oklahoma City, OK 73106 | Oil & Gas Operator | Nov 2016 |
| 387 | Mustang Fuel Corporation | Oklahoma City, OK 73114 | Oil & Gas Operator | May 2025 |
| 388 | Mustang Gas Products LLC | Oklahoma City, OK 73114-7406 | Oil & Gas Operator | Sep 2022 |
| 389 | MW Petroleum Corporation | Houston, TX 77056 | Oil & Gas Operator | Mar 2015 |
| 390 | Nadel And Gussman, L.L.C. | Tulsa, OK 74119 | Oil & Gas Operator | Jul 2025 |
| 391 | National Energy Group, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Sep 2014 |
| 392 | National Oil Company (Ohio) The | Columbus, OH 43215 | Oil & Gas Operator | Sep 1999 |
| 393 | Neg Operating LLC | Oklahoma City, OK 73101 | Oil & Gas Operator | Nov 2024 |
| 394 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | Jul 2025 |
| 395 | Noble Energy Production Inc | Houston, TX 77067 | Oil & Gas Operator | Jul 2025 |
| 396 | North American Royalties, Inc. | Chattanooga, TN 37408 | Oil & Gas Operator | Oct 2001 |
| 397 | North Lake Resources LLC | Oklahoma City, OK 73132 | Oil & Gas Operator | Jul 2025 |
| 398 | Oil Producers, Inc. Of Kansas | Wichita, KS 67206 | Oil & Gas Operator | Jul 2025 |
| 399 | Oilsearch Corporation | Albuquerque, NM 87109 | Oil & Gas Operator | Feb 1994 |
| 400 | Oklahoma Oil & Gas MGMT Inc | Edmond, OK 73083-6786 | Oil & Gas Operator | Apr 2025 |