| 301 | Lime Rock Resources IV-A, L.P. | Houston, TX 77002 | Oil & Gas Operator | Dec 2025 |
| 302 | Lincoln Rock Corporation | Northfield, IL 60093 | Oil & Gas Operator | Jul 2003 |
| 303 | Loki Oil LLC | Cushing, OK 74023 | Oil & Gas Operator | Nov 2024 |
| 304 | Long Production LLC | Claremore, OK 74017-2808 | Oil & Gas Operator | Oct 2019 |
| 305 | Longacre Oil & Gas | Enid, OK 73702 | Oil & Gas Operator | Mar 2013 |
| 306 | Longberry Energy Inc | Keota, OK 74941 | Gas Operator | Sep 2025 |
| 307 | Lubell Oil Company | Tulsa, OK 74103 | Gas Operator | Jul 1993 |
| 308 | LXS Inc | Stigler, OK 74462-0506 | Gas Operator | Nov 2013 |
| 309 | Lyons & Lyons Inc | Tulsa, OK 74119 | Oil & Gas Operator | Aug 2025 |
| 310 | M E Klein & Associates LLC | Washington, OK 73093-4663 | Oil & Gas Operator | Sep 2025 |
| 311 | M M Energy Inc | Oklahoma City, OK 73156 | Oil & Gas Operator | Aug 2025 |
| 312 | M. M. & M. Resources, Inc. | Wetumka, OK 74883 | Oil & Gas Operator | Apr 2020 |
| 313 | Manuel Corporation | Wichita, KS 67206 | Oil & Gas Operator | Sep 2025 |
| 314 | Marathon Oil Company LLC | Houston, TX 77079 | Oil & Gas Operator | Sep 2025 |
| 315 | Marbet LLC | Edmond, OK 73013-6691 | Oil & Gas Operator | Sep 2025 |
| 316 | Mark L Shidler Inc | Houston, TX 77055 | Oil & Gas Operator | Sep 2025 |
| 317 | Massad Oil Company | Holdenville, OK 74848-2629 | Oil Operator | Aug 2025 |
| 318 | Maverick Brothers Resources LLC | Enid, OK 73701 | Oil & Gas Operator | Aug 2025 |
| 319 | Mayabb Oil Company Inc | Tulsa, OK 74105-5158 | Oil & Gas Operator | Jul 2025 |
| 320 | Mayfield Engineering Service | Tulsa, OK 74104 | Oil & Gas Operator | Dec 2025 |
| 321 | McMahon Operating Co., L.C. | Pampa, TX 79066 | Oil & Gas Operator | Dec 2004 |
| 322 | Meade Energy Corporation | Oklahoma City, OK 73118-4015 | Oil & Gas Operator | Sep 2025 |
| 323 | Meade James C | Oklahoma City, OK 73118-1544 | Gas Operator | Apr 2015 |
| 324 | Meadowbrook Oil Corporation Of Ok Inc | Del City, OK 73115-3608 | Oil & Gas Operator | Sep 2025 |
| 325 | Mega Natural Gas Co | Tulsa, OK 74133 | Oil & Gas Operator | Jul 1996 |
| 326 | Mer Resources Inc | Edmond, OK 73013-7662 | Oil & Gas Operator | Mar 2015 |
| 327 | Mercer Oil Co | Stratford, OK 74872-7426 | Oil & Gas Operator | Aug 2025 |
| 328 | Meridian Oil Production Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 2024 |
| 329 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Dec 2025 |
| 330 | Mesa Operating LP | Irving, TX 75039-3746 | Oil & Gas Operator | Oct 2010 |
| 331 | MFP Petroleum LP | Oklahoma City, OK 73142-3017 | Gas Operator | Jul 2025 |
| 332 | Midwest Energy Corporation | Tulsa, OK 74105-6083 | Oil & Gas Operator | Aug 2016 |
| 333 | Midwest Eor Inc | Tulsa, OK 74105-6059 | Oil & Gas Operator | May 2013 |
| 334 | Mikco Inc | Tulsa, OK 74133 | Oil & Gas Operator | May 2001 |
| 335 | Miller Exploration Company | Tulsa, OK 74136-1020 | Oil & Gas Operator | Mar 2015 |
| 336 | MJM Oil & Gas, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Aug 2003 |
| 337 | Monarch Energy Company LLC | Eufaula, OK 74432 | Oil & Gas Operator | Sep 2025 |
| 338 | Monroe Natural Gas Inc | Norman, OK 73071 | Oil & Gas Operator | Aug 2025 |
| 339 | Moze Inc | Ochelata, OK 74051 | Oil & Gas Operator | Jan 2001 |
| 340 | Mueller Thomas C | Fort Smith, AR 72913 | Gas Operator | Aug 2008 |
| 341 | Muirfield Resources Company | Tulsa, OK 74101-3166 | Oil & Gas Operator | Jun 2024 |
| 342 | Mullins Jimmy R Dba Southcreek Petroleum Co | Dibble, OK 73031 | Oil & Gas Operator | Jan 2021 |
| 343 | Mustang Fuel Corporation | Oklahoma City, OK 73114 | Oil & Gas Operator | Sep 2025 |
| 344 | Mustang Gas Products LLC | Oklahoma City, OK 73114-7406 | Oil & Gas Operator | Sep 2022 |
| 345 | Nadel And Gussman LLC | Tulsa, OK 74119 | Oil & Gas Operator | Dec 2025 |
| 346 | National Energy Group Inc | Dallas, TX 75206 | Oil & Gas Operator | Sep 2014 |
| 347 | Nbi Services, Inc. | Tulsa, OK 74159 | Oil & Gas Operator | Dec 2025 |
| 348 | Neg Operating LLC | Oklahoma City, OK 73101 | Oil & Gas Operator | Aug 2025 |
| 349 | Neok Production Company LLC | Nowata, OK 74048 | Oil & Gas Operator | Aug 2025 |
| 350 | NFC Petroleum Corporation | Tulsa, OK 74121 | Oil & Gas Operator | Jun 1996 |
| 351 | Njre Operating Company | Tulsa, OK 74119 | Gas Operator | Dec 2016 |
| 352 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | Dec 2025 |
| 353 | Noble Energy Production Inc | Houston, TX 77067 | Oil & Gas Operator | Dec 2025 |
| 354 | Northbrook Oil & Gas Co LLC | Norman, OK 73072 | Oil & Gas Operator | Nov 2014 |
| 355 | Nye Oil Company | Oklahoma City, OK 73118-1245 | Oil & Gas Operator | Jun 2004 |
| 356 | O G & E | Oklahoma City, OK 73124 | Oil & Gas Operator | Feb 2014 |
| 357 | O.G.P. Operating, Inc. | Dallas, TX 75231 | Oil & Gas Operator | Dec 2025 |
| 358 | Oak Hills Drilling & Oper., LLC | Holdenville, OK 74848 | Oil & Gas Operator | May 2013 |
| 359 | Oak Hills Energy Inc | Holdenville, OK 74848-0470 | Oil & Gas Operator | Sep 2014 |
| 360 | Oex-1 LLC | Tulsa, OK 74105-5153 | Oil & Gas Operator | Mar 2024 |
| 361 | Offield Lease Operations LLC | Wilson, OK 73463 | Oil & Gas Operator | May 2023 |
| 362 | Oil Center Operating Inc | Fort Worth, TX 76102-5108 | Oil & Gas Operator | Apr 2014 |
| 363 | Oklahoma Oil & Gas MGMT Inc | Edmond, OK 73083-6786 | Oil & Gas Operator | Aug 2025 |
| 364 | Okland Oil Company | Oklahoma City, OK 73102-9022 | Oil & Gas Operator | Sep 2025 |
| 365 | Old Dominion Oil Corporation | Oklahoma City, OK 73107 | Oil & Gas Operator | Apr 2009 |
| 366 | Oneok Exploration Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 367 | Oneok Gas Processing LLC | Tulsa, OK 74103 | Oil & Gas Operator | May 2018 |
| 368 | Oneok Gas Transportation Co | Tulsa, OK 74121-2089 | Oil & Gas Operator | Oct 2014 |
| 369 | Oneok Resources Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 370 | Orca Operating Company LLC | Houston, TX 77056 | Oil & Gas Operator | Sep 2025 |
| 371 | Otc Petroleum Corporation | Nichols Hill, OK 73116 | Oil & Gas Operator | Mar 2015 |
| 372 | Ouachita Exploration Inc | Chickasha, OK 73018 | Oil & Gas Operator | Aug 2025 |
| 373 | Ovintiv Mid-Continent Inc. | The Woodlands, TX 77380-2764 | Oil & Gas Operator | Aug 2025 |
| 374 | Oxley Energy LLC | Houston, TX 77042 | Gas Operator | Sep 2025 |
| 375 | Oxley Petroleum | Tulsa, OK 74119-3609 | Oil & Gas Operator | Jan 2020 |
| 376 | Oxley Petroleum Company | Oklahoma City, OK 73118-1044 | Oil & Gas Operator | Sep 2017 |
| 377 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Dec 2025 |
| 378 | P.O.&G. Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Dec 2025 |
| 379 | Pacific Enterprise Oil Co USA | Los Angeles, CA 90071-2005 | Oil & Gas Operator | Aug 2012 |
| 380 | Paleo, Inc. | Oklahoma City, OK 73112 | Oil & Gas Operator | Dec 2025 |
| 381 | Paloma Operating Co Inc | Houston, TX 77002-5220 | Oil & Gas Operator | Jul 2025 |
| 382 | Paloma Resources, LLC | Houston, TX 77002 | Oil & Gas Operator | Jun 2018 |
| 383 | Palomino Petroleum Inc | Newton, KS 67114 | Oil & Gas Operator | Jun 2025 |
| 384 | Patina Oil & Gas Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2016 |
| 385 | Patrick Exploration Company | Tulsa, OK 74136 | Oil & Gas Operator | Apr 2011 |
| 386 | Payrock Energy LLC | Oklahoma City, OK 73134-2612 | Oil & Gas Operator | Feb 2023 |
| 387 | Pelican Production Company | New Orleans, LA 70130-2477 | Oil & Gas Operator | Mar 2014 |
| 388 | Pengo Petroleum Inc | | Oil & Gas Operator | Dec 2013 |
| 389 | Penn VIrginia MC Operating Co LLC | Houston, TX 77084-7213 | Oil & Gas Operator | Sep 2025 |
| 390 | Permian West Corp. | Odessa, TX 79762 | Oil & Gas Operator | Dec 2025 |
| 391 | Petrocorp Incorporated | Tulsa, OK 74170 | Oil & Gas Operator | Nov 2021 |
| 392 | Petrohawk Operating Company | Houston, TX 77056 | Oil & Gas Operator | Oct 2021 |
| 393 | Petroleum Development Company | Tulsa, OK 74103 | Oil & Gas Operator | Aug 2025 |
| 394 | Petroleum Explo Prod Inc | Oilton, OK 74052 | Oil & Gas Operator | Jan 2017 |
| 395 | Petroquest Energy, L.L.C. | Lafayette, LA 70505 | Oil & Gas Operator | Dec 2025 |
| 396 | Pinnacle Corporation (The) | Broken Arrow, OK 74012 | Oil & Gas Operator | Nov 2014 |
| 397 | Piper Operating LLC | Stigler, OK 74462 | Oil & Gas Operator | Sep 2025 |
| 398 | Powell Oil | Healdton, OK 73438-4463 | Oil & Gas Operator | Sep 2025 |
| 399 | Primexx Operating Corporation | Dallas, TX 75206 | Oil & Gas Operator | Mar 2024 |
| 400 | Prize Operating Company | Grapevine, TX 76051 | Oil & Gas Operator | Aug 2016 |