| 301 | Ladd Petroleum Corp. | Denver, CO 80202 | Oil & Gas Operator | Oct 2004 |
| 302 | Laredo Petroleum Inc | Tulsa, OK 74120 | Oil & Gas Operator | Mar 2023 |
| 303 | Lariat Petroleum Inc | Tulsa, OK 74119 | Oil & Gas Operator | Sep 2024 |
| 304 | Latex Petroleum Corp. | Houston, TX 77090 | Oil & Gas Operator | Aug 2012 |
| 305 | Latigo Oil & Gas, Inc. | Woodward, OK 73801 | Oil & Gas Operator | Dec 2025 |
| 306 | Latigo Petroleum LLC | Pampa, TX 79066 | Oil & Gas Operator | Feb 2026 |
| 307 | Laurco Energies,Inc | | Oil & Gas Operator | May 2025 |
| 308 | LCB Resources LLC | Kingfisher, OK 73750-2322 | Oil & Gas Operator | Dec 2025 |
| 309 | Lear Petroleum Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | Aug 1999 |
| 310 | Liberty Operating Inc | Norman, OK 73069-8225 | Oil & Gas Operator | Dec 2024 |
| 311 | Little H L | Bristow, OK 74010 | Gas Operator | Sep 1994 |
| 312 | Lone Tree Oil & Gas LLC | Greenwood VLG, CO 80111 | Oil & Gas Operator | Feb 2026 |
| 313 | Lorentz Oil & Gas LLC | Edmond, OK 73034-7266 | Oil & Gas Operator | Nov 2025 |
| 314 | Louisiana Land & Exploration Co. | Houston, TX 77210 | Oil & Gas Operator | Sep 2013 |
| 315 | LX4, LLC | | Oil Operator | Dec 2025 |
| 316 | Mack Energy Co. | Duncan, OK 73534 | Oil & Gas Operator | Dec 2025 |
| 317 | Mackellar Inc | Oklahoma City, OK 73116-7101 | Oil & Gas Operator | Dec 2025 |
| 318 | Malson Oil Company | Crawford, OK 73638 | Oil & Gas Operator | Dec 2016 |
| 319 | Manuel Corporation | Wichita, KS 67206 | Oil & Gas Operator | Dec 2025 |
| 320 | Marathon Oil Company LLC | Houston, TX 77079 | Oil & Gas Operator | Dec 2025 |
| 321 | Mark L Shidler Inc | Houston, TX 77055 | Oil & Gas Operator | Dec 2025 |
| 322 | Marlin Oil Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Nov 2025 |
| 323 | Marsh Operating Company | Dallas, TX 75221 | Oil & Gas Operator | Sep 2025 |
| 324 | Martin Jr, James U | | Oil & Gas Operator | Nov 2025 |
| 325 | Martin'S Resources LLC | Woodward, OK 73801-5641 | Oil & Gas Operator | Nov 2025 |
| 326 | Maverick Brothers Resources LLC | Enid, OK 73701 | Oil & Gas Operator | Nov 2025 |
| 327 | McNic Oil & Gas Midcontinent | Oklahoma City, OK 73154-0526 | Oil & Gas Operator | May 2024 |
| 328 | McOr Oil & Gas Corp | Houston, TX 77002 | Oil & Gas Operator | Oct 2013 |
| 329 | Meade Energy Corporation | Oklahoma City, OK 73118-4015 | Oil & Gas Operator | Dec 2025 |
| 330 | Meadowbrook Oil Corporation Of Ok Inc | Del City, OK 73115-3608 | Oil & Gas Operator | Dec 2025 |
| 331 | Meridian Oil Production Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 2024 |
| 332 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Feb 2026 |
| 333 | Mesa Operating LP | Irving, TX 75039-3746 | Oil & Gas Operator | Oct 2010 |
| 334 | Mewbourne Marketing, Inc. | | Oil & Gas Operator | Mar 2013 |
| 335 | Mewbourne Oil Company | Tyler, TX 75711 | Oil & Gas Operator | Feb 2026 |
| 336 | Mge Resources, Inc. | Perryton, TX 79070 | Oil & Gas Operator | Nov 2025 |
| 337 | Mid Center Oil Company | | Oil & Gas Operator | Mar 2014 |
| 338 | Mid-Con Central Expl Co | Tulsa, OK 74136 | Oil & Gas Operator | Aug 2014 |
| 339 | Midgard Energy Company | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2014 |
| 340 | Milmac Operating Company | Lubbock, TX 79408-2976 | Oil & Gas Operator | Sep 2004 |
| 341 | Morris Ed Dba Morris Operating Company | Mounds, OK 74047-4801 | Oil & Gas Operator | Dec 2025 |
| 342 | MT Energy LLC | Waskom, TX 75692 | Oil & Gas Operator | Feb 2026 |
| 343 | Muirfield Resources Company | Tulsa, OK 74101-3166 | Oil & Gas Operator | Jun 2024 |
| 344 | Muras Energy Inc | Edmond, OK 73013 | Oil & Gas Operator | Nov 2025 |
| 345 | Mustang Fuel Corporation | Oklahoma City, OK 73114 | Oil & Gas Operator | Dec 2025 |
| 346 | MW Petroleum Corporation | Houston, TX 77056 | Oil & Gas Operator | Mar 2015 |
| 347 | Nadel And Gussman LLC | Tulsa, OK 74119 | Oil & Gas Operator | Feb 2026 |
| 348 | National Energy Group Inc | Dallas, TX 75206 | Oil & Gas Operator | Sep 2014 |
| 349 | National Oil Company | Garden City, KS 67846 | Oil & Gas Operator | Jun 2024 |
| 350 | Natural Gas Pipeline Co Of Am LLC | Downers Grove, IL 60515-3708 | Oil & Gas Operator | Mar 2015 |
| 351 | Neg Operating LLC | Oklahoma City, OK 73101 | Oil & Gas Operator | Aug 2025 |
| 352 | Newpark Drilling Fluids LLC | Clinton, OK 73601 | Oil Operator | Dec 2013 |
| 353 | Nexstreem Corporation | | Oil & Gas Operator | Dec 2020 |
| 354 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | Feb 2026 |
| 355 | Noble Energy Production Inc | Houston, TX 77067 | Oil & Gas Operator | Feb 2026 |
| 356 | Nogp Operating Company Inc | Tomball, TX 77377 | Oil & Gas Operator | Dec 2025 |
| 357 | Nordstrand Engineering Inc | Houston, TX 77019 | Oil & Gas Operator | Feb 2026 |
| 358 | North American Royalties, Inc. | Chattanooga, TN 37408 | Oil & Gas Operator | Oct 2001 |
| 359 | North Central Casing Puller Inc | Graham, TX 76450 | Oil & Gas Operator | Jan 1999 |
| 360 | Northwest Exploration Co | Salt Lake City, UT 84108-0900 | Oil & Gas Operator | Sep 1991 |
| 361 | Nova Energy Corporation | Denver, CO 80201 | Oil & Gas Operator | Jun 2003 |
| 362 | O G & E | Oklahoma City, OK 73124 | Oil & Gas Operator | Feb 2014 |
| 363 | Oakland Petroleum Oper Co., Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Feb 2026 |
| 364 | Occidental Pet Corp | Houston, TX 77046 | Oil & Gas Operator | Oct 1997 |
| 365 | Oklahoma Oil Tactics Inc | Edmond, OK 73003-1351 | Oil & Gas Operator | Mar 2015 |
| 366 | Okland Oil Company | Oklahoma City, OK 73102-9022 | Oil & Gas Operator | Dec 2025 |
| 367 | Old Dominion Oil Corporation | Oklahoma City, OK 73107 | Oil & Gas Operator | Apr 2009 |
| 368 | Oneok Field Services Company | Tulsa, OK 74103 | Oil & Gas Operator | Jul 2022 |
| 369 | Oneok Gas Processing LLC | Tulsa, OK 74103 | Oil & Gas Operator | May 2018 |
| 370 | Oneok Resources Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 371 | Opal Operating Company LLC | Edmond, OK 73013 | Oil & Gas Operator | Feb 2026 |
| 372 | Overflow Energy, LLC | Perryton, TX 79070 | Oil & Gas Operator | Feb 2026 |
| 373 | Ovintiv Mid-Continent Inc. | The Woodlands, TX 77380-2764 | Oil & Gas Operator | Dec 2025 |
| 374 | Oxley Petroleum | Tulsa, OK 74119-3609 | Oil & Gas Operator | Jan 2020 |
| 375 | Oxley Petroleum Company | Oklahoma City, OK 73118-1044 | Oil & Gas Operator | Sep 2017 |
| 376 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Feb 2026 |
| 377 | Pacific Enterprise Oil Co USA | Los Angeles, CA 90071-2005 | Oil & Gas Operator | Aug 2012 |
| 378 | Pacific Enterprises Royalty Co | Oklahoma City, OK 73101 | Oil & Gas Operator | Feb 2002 |
| 379 | Paleo, Inc. | Oklahoma City, OK 73112 | Oil & Gas Operator | Feb 2026 |
| 380 | Panhandle Oil & Gas Inc | Oklahoma City, OK 73112-5688 | Oil & Gas Operator | May 2007 |
| 381 | Pantera Energy Company | Amarillo, TX 79101 | Oil & Gas Operator | Feb 2026 |
| 382 | Panther Energy Company, LLC | Tulsa, OK 74103 | Oil & Gas Operator | May 2022 |
| 383 | Pardee Production Co. | Skiatook, OK 74070 | Oil & Gas Operator | Mar 2021 |
| 384 | Park Avenue Exploration Corp | Oklahoma City, OK 73102-5604 | Oil & Gas Operator | Sep 2011 |
| 385 | Parker & Parsley Dev Co | Midland, TX 79702 | Oil & Gas Operator | Mar 2015 |
| 386 | Parker & Parsley Dev LP | Irving, TX 75039-3745 | Oil & Gas Operator | Mar 2015 |
| 387 | Patina Oil & Gas Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2016 |
| 388 | Pegasus Energy Corporation | Oklahoma City, OK 73162 | Oil & Gas Operator | Mar 2015 |
| 389 | Pelican Production Company | New Orleans, LA 70130-2477 | Oil & Gas Operator | Mar 2014 |
| 390 | Pennzoil Company | Midland, TX 79710-0090 | Oil & Gas Operator | Mar 2000 |
| 391 | Pennzoil Explor & Prod Co | Houston, TX 77002 | Oil & Gas Operator | Mar 2000 |
| 392 | Petrocorp Incorporated | Tulsa, OK 74170 | Oil & Gas Operator | Nov 2021 |
| 393 | Petrohawk Operating Company | Houston, TX 77056 | Oil & Gas Operator | Oct 2021 |
| 394 | Petroleum Development Company | Tulsa, OK 74103 | Oil & Gas Operator | Nov 2025 |
| 395 | Petroleum International, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Feb 2000 |
| 396 | Petroleum Investment Inc | Oklahoma City, OK 73118 | Oil & Gas Operator | Nov 1998 |
| 397 | Petroleum Properties MGMT. Co. | Oklahoma City, OK 73118 | Oil & Gas Operator | Dec 2014 |
| 398 | Petroquest Energy, L.L.C. | Lafayette, LA 70505 | Oil & Gas Operator | Feb 2026 |
| 399 | Petrotex, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Aug 2003 |
| 400 | Pioneer Resources Prod LP | Irving, TX 75039-3745 | Oil & Gas Operator | Feb 2005 |