| 301 | Kepco. Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2015 |
| 302 | Kerr McGee Rocky MTN Corp | Denver, CO 80202-5736 | Oil & Gas Operator | Mar 2015 |
| 303 | Kerr-McGee Corporation | Dallas, TX 75380 | Oil & Gas Operator | Mar 2025 |
| 304 | Kerr-McGee Oil & Gas Onshore LLC | The Woodlands, TX 77380 | Oil & Gas Operator | Feb 2017 |
| 305 | Kerr-McGee Oil & Gas Onshore LP | Houston, TX 77046 | Oil & Gas Operator | May 2025 |
| 306 | Kimball Production Co. | Houston, TX 77042 | Oil & Gas Operator | Jul 2002 |
| 307 | Kirkpatrick Oil Company | Nichols Hill, OK 73116 | Oil & Gas Operator | May 2025 |
| 308 | Koch Oil Company | | Oil & Gas Operator | May 2017 |
| 309 | KT Energy Inc | Enid, OK 73702-2365 | Oil & Gas Operator | Feb 2025 |
| 310 | KWB Oil Property Management Inc | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2025 |
| 311 | L & L Smith Energy Corporation | Muskogee, OK 74403-8479 | Oil & Gas Operator | Jan 2023 |
| 312 | Lamb Alan L | Oklahoma City, OK 73120-7824 | Oil & Gas Operator | Feb 2020 |
| 313 | Landmark Exploration Co | Tulsa, OK 74103 | Oil & Gas Operator | Oct 2013 |
| 314 | Lariat Petroleum Inc | Tulsa, OK 74119 | Oil & Gas Operator | Sep 2024 |
| 315 | Larkspur Operating LLC | Oklahoma City, OK 73034 | Oil & Gas Operator | Mar 2025 |
| 316 | Latigo Oil And Gas Inc | Woodward, OK 73801 | Oil & Gas Operator | Mar 2025 |
| 317 | LCB Resources LLC | Kingfisher, OK 73750-2322 | Oil & Gas Operator | Mar 2025 |
| 318 | Lear Petroleum Corp | Houston, TX 77210 | Oil & Gas Operator | Mar 2015 |
| 319 | Lewis A Hembree Production Co | Shawnee, OK 74801 | Oil & Gas Operator | Feb 2025 |
| 320 | Liberty Operating Inc | Norman, OK 73069-8225 | Oil & Gas Operator | Dec 2024 |
| 321 | Lime Rock Resources A, L.P. | Houston, TX 77002 | Oil & Gas Operator | Feb 2025 |
| 322 | Lime Rock Resources II-A, L.P. | Houston, TX 77002 | Oil & Gas Operator | Feb 2025 |
| 323 | Litzenberger Exploration | Waynoka, OK 73860 | Oil & Gas Operator | Jul 1996 |
| 324 | Litzenberger Exploration Inc | Waynoka, OK 73860 | Oil & Gas Operator | Mar 2025 |
| 325 | Lobo Exploration Company | Yukon, OK 73099 | Oil & Gas Operator | Feb 2025 |
| 326 | Locin Oil Corporation | Katy, TX 77494 | Oil & Gas Operator | May 2025 |
| 327 | Lowry Exploration Inc | Tulsa, OK 74119 | Oil & Gas Operator | Mar 2025 |
| 328 | LX4, LLC | | Oil Operator | Mar 2025 |
| 329 | Lyons & Lyons Inc | Tulsa, OK 74119 | Oil & Gas Operator | Feb 2025 |
| 330 | M & M Exploration, Inc. | Westminster, CO 80031 | Oil & Gas Operator | Mar 2025 |
| 331 | M3V Energy, LLC | Perryton, TX 79070 | Oil & Gas Operator | May 2025 |
| 332 | Mack Energy Co. | Duncan, OK 73534 | Oil & Gas Operator | Mar 2025 |
| 333 | Malson Oil Company | Crawford, OK 73638 | Oil & Gas Operator | Dec 2016 |
| 334 | Manuel Corporation | Wichita, KS 67206 | Oil & Gas Operator | Mar 2025 |
| 335 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Mar 2025 |
| 336 | Marjo Operating Mid-Continent LLC | Tulsa, OK 74103 | Oil & Gas Operator | Mar 2025 |
| 337 | Mark L Shidler Inc | Houston, TX 77055 | Oil & Gas Operator | Mar 2025 |
| 338 | Marlin Oil Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Feb 2025 |
| 339 | Marmik Oil Company | El Dorado, AR 71730 | Oil & Gas Operator | Jan 2015 |
| 340 | Marshall Oil Corporation | Oklahoma City, OK 73154 | Oil & Gas Operator | Apr 2017 |
| 341 | Martin'S Resources LLC | Woodward, OK 73801-5641 | Oil & Gas Operator | Feb 2025 |
| 342 | Matador E & P Company Inc | | Oil & Gas Operator | May 2020 |
| 343 | May Petroleum, Inc. | Dallas, TX 75231 | Oil & Gas Operator | Nov 1998 |
| 344 | MBR Resources, Inc. | Tulsa, OK 74119 | Oil & Gas Operator | May 2025 |
| 345 | McGee, Tom Corporation | Booker, TX 79005 | Oil & Gas Operator | Feb 2025 |
| 346 | McNic Oil & Gas Midcontinent | Oklahoma City, OK 73154-0526 | Oil & Gas Operator | May 2024 |
| 347 | McQueen Ed & Company Inc | Lindsey, OK 73052 | Oil & Gas Operator | Apr 2014 |
| 348 | Meadowbrook Oil Corporation Of Ok Inc | Del City, OK 73115-3608 | Oil & Gas Operator | Mar 2025 |
| 349 | Medallion Petroleum, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2015 |
| 350 | Meridian Oil Production Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 2024 |
| 351 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | May 2025 |
| 352 | Mesa Operating LP | Irving, TX 75039-3746 | Oil & Gas Operator | Oct 2010 |
| 353 | Metropolitan Resources Corp | Tulsa, OK 74169-1734 | Oil & Gas Operator | Mar 2015 |
| 354 | Mewbourne Marketing, Inc. | | Oil & Gas Operator | Mar 2013 |
| 355 | Mewbourne Oil Company | Tyler, TX 75711 | Oil & Gas Operator | May 2025 |
| 356 | MFP Petroleum LP | Oklahoma City, OK 73142-3017 | Gas Operator | Feb 2025 |
| 357 | Mge Resources, Inc. | Perryton, TX 79070 | Oil & Gas Operator | Feb 2025 |
| 358 | Mid-Con Central Expl Co | Tulsa, OK 74136 | Oil & Gas Operator | Aug 2014 |
| 359 | Midgard Energy Company | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2014 |
| 360 | Midwestern Exploration Co. | Edmond, OK 73013 | Oil & Gas Operator | Jan 2025 |
| 361 | Mija LLC | Oklahoma City, OK 73151 | Oil & Gas Operator | Mar 2025 |
| 362 | Miller Oil & Gas Co | Okmulgee, OK 74447 | Oil & Gas Operator | Oct 2017 |
| 363 | Mobil Exp & Prod Us Inc | Houston, TX 77060-1991 | Oil & Gas Operator | May 2001 |
| 364 | Monexco | Edmond, OK 73034-3776 | Oil & Gas Operator | Mar 2008 |
| 365 | Monterey Production Company LLC | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2025 |
| 366 | Moore & Moore Energy Inc | Purcell, OK 73080-0674 | Oil & Gas Operator | Dec 2012 |
| 367 | Moore Robert L | Perryton, TX 79070-1275 | Oil & Gas Operator | Apr 2020 |
| 368 | Moss Ted A Operating Company | Oklahoma City, OK 73126-0187 | Oil & Gas Operator | Jun 1997 |
| 369 | Mott Energy LLC | Riverview, FL 33569-6702 | Oil & Gas Operator | Sep 2024 |
| 370 | Muras Energy Inc | Edmond, OK 73013 | Oil & Gas Operator | Feb 2025 |
| 371 | Mustang Fuel Corp. Of Oklahoma | Oklahoma City, OK 73106 | Oil & Gas Operator | Nov 2016 |
| 372 | Mustang Fuel Corporation | Oklahoma City, OK 73114 | Oil & Gas Operator | Mar 2025 |
| 373 | Nadel And Gussman, L.L.C. | Tulsa, OK 74119 | Oil & Gas Operator | May 2025 |
| 374 | Nard Inc | Buffalo, OK 73834-9737 | Oil Operator | Dec 2005 |
| 375 | National Cooperative RFG Assoc | McPherson, KS 67460-1404 | Oil & Gas Operator | Jun 2006 |
| 376 | National Oil Company | Garden City, KS 67846 | Oil & Gas Operator | Jun 2024 |
| 377 | Natural Gas Anadarko Company | Perryton, TX 79070 | Oil & Gas Operator | May 2025 |
| 378 | Natural Gas Compression Corp | Cleveland, OK 74020 | Oil & Gas Operator | Jan 2025 |
| 379 | Natural Gas Pipeline Co Of Am LLC | Downers Grove, IL 60515-3708 | Oil & Gas Operator | Mar 2015 |
| 380 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | May 2025 |
| 381 | Northwest Disposal Corporation | Laverne, OK 73848-0504 | Oil & Gas Operator | Jul 2014 |
| 382 | O G & E | Oklahoma City, OK 73124 | Oil & Gas Operator | Feb 2014 |
| 383 | O K Swabbing Inc | Hennessey, OK 73742 | Oil & Gas Operator | Feb 2025 |
| 384 | O'Brien Energy Resources Corp | Portsmouth, NH 03801 | Oil & Gas Operator | May 2025 |
| 385 | O'Neill Properties, LTD. | Midland, TX 79702 | Oil & Gas Operator | May 2025 |
| 386 | Oexco, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2015 |
| 387 | Oil Producers, Inc. Of Kansas | Wichita, KS 67206 | Oil & Gas Operator | May 2025 |
| 388 | Okie Crude Company | Tulsa, OK 74103 | Oil & Gas Operator | Feb 2025 |
| 389 | Oklahoma Oil & Gas MGMT Inc | Edmond, OK 73083-6786 | Oil & Gas Operator | Feb 2025 |
| 390 | Oklahoma Oil Tactics Inc | Edmond, OK 73003-1351 | Oil & Gas Operator | Mar 2015 |
| 391 | Okland Oil Company | Oklahoma City, OK 73102-9022 | Oil & Gas Operator | Mar 2025 |
| 392 | Oneok Exploration Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 393 | Oneok Field Services Company | Tulsa, OK 74103 | Oil & Gas Operator | Jul 2022 |
| 394 | Oneok Resources Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 395 | Onshore Royalties LLC | Houston, TX 77269 | Oil & Gas Operator | Mar 2025 |
| 396 | Orca Operating Company LLC | Houston, TX 77056 | Oil & Gas Operator | Mar 2025 |
| 397 | Otc Petroleum Corporation | Nichols Hill, OK 73116 | Oil & Gas Operator | Mar 2015 |
| 398 | Ovintiv Mid-Continent Inc. | The Woodlands, TX 77380-2764 | Oil & Gas Operator | Mar 2025 |
| 399 | Oxley Petroleum Co | Oklahoma City, OK 73118-1044 | Oil & Gas Operator | Sep 2017 |
| 400 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | May 2025 |