| 301 | Nomeco Oil & Gas Co. | Jackson, MI 49204 | Oil & Gas Operator | Dec 1994 |
| 302 | Norcen Explorer, Inc. | Houston, TX 77079 | Oil & Gas Operator | May 1998 |
| 303 | North Central Oil Corp | Houston, TX 77252 | Oil & Gas Operator | Dec 2005 |
| 304 | Oak Energy, LLC | Houston, TX 77027 | Oil & Gas Operator | Jul 2025 |
| 305 | Ocean Energy, Inc. | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 306 | Odegard Energy, Inc. | Houston, TX 77024 | Oil & Gas Operator | Jul 2020 |
| 307 | Ogden Resources Corporation | Bryan, TX 77802 | Oil & Gas Operator | Jul 2025 |
| 308 | Ogden Resources, LTD. | Bryan, TX 77802 | Oil & Gas Operator | Feb 2009 |
| 309 | Oil Management Corporation | Dallas, TX 75206 | Oil & Gas Operator | Apr 2022 |
| 310 | Oro Resources, LLC | Houston, TX 77024 | Oil & Gas Operator | Jul 2025 |
| 311 | Ovintiv USA Inc. | Denver, CO 80202 | Oil & Gas Operator | Jul 2025 |
| 312 | Ows Energy, Inc. | Montgomery, TX 77356 | Oil & Gas Operator | Jul 2025 |
| 313 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Jul 2025 |
| 314 | P & C Oil Company | Leona, TX 75850 | Oil & Gas Operator | May 2025 |
| 315 | Palisades Operating Company | Midland, TX 79702 | Oil & Gas Operator | Jul 2025 |
| 316 | Palmer Petroleum Inc. | Shreveport, LA 71105 | Oil & Gas Operator | Jul 2025 |
| 317 | Par Minerals Corporation | Shreveport, LA 71101 | Oil & Gas Operator | Jul 2025 |
| 318 | Paradigm Exploration, L.P. | La Grange, TX 78945 | Oil Operator | Sep 2008 |
| 319 | Paragon Energy, Inc. | Dallas, TX 75244 | Oil & Gas Operator | Jul 2025 |
| 320 | Pardus Oil & Gas Operating, LP | Tulsa, OK 74114 | Oil & Gas Operator | Apr 2022 |
| 321 | Parker & Parsley Development L.P | Midland, TX 79702 | Oil & Gas Operator | Oct 2007 |
| 322 | Patriot Operating Company, Inc. | Houston, TX 77008 | Oil & Gas Operator | Sep 2003 |
| 323 | Peak Natural Gas Co., LLC | Dallas, TX 75225 | Oil & Gas Operator | Sep 2010 |
| 324 | Pendolino Resources, LLC | Dallas, TX 75205 | Gas Operator | Mar 2023 |
| 325 | Penroc Oil Corp. | Hobbs, NM 88241 | Oil & Gas Operator | May 2025 |
| 326 | Perry Producing Company, Inc. | Ackerly, TX 79713 | Oil & Gas Operator | Jul 2025 |
| 327 | Perryman Operating Company | Athens, TX 75751 | Oil & Gas Operator | Jul 2025 |
| 328 | Petro-Hunt, L.L.C. | Dallas, TX 75201 | Oil & Gas Operator | Jul 2025 |
| 329 | Petro-Smith Operating LLC | Houston, TX 77010 | Oil & Gas Operator | Jul 2025 |
| 330 | Petrogulf Corporation | Denver, CO 80202 | Oil & Gas Operator | Jul 2025 |
| 331 | PG&E Resources Company | Houston, TX 77042 | Oil & Gas Operator | May 1995 |
| 332 | Phoenix Hydrocarbons Operating | Midland, TX 79702 | Oil & Gas Operator | Jun 2024 |
| 333 | Pioneer Natural Res. USA, Inc. | Spring, TX 77389 | Oil & Gas Operator | Jul 2025 |
| 334 | Pitco Investments, LTD. | Scottsdale, AZ 85261 | Oil & Gas Operator | Jan 2013 |
| 335 | Plains Marketing, LP | Cushing, OK 74023 | Oil Operator | Jan 2012 |
| 336 | Pmo | Garland, TX 75040 | Oil & Gas Operator | Feb 2018 |
| 337 | Powerline Energy Corporation | Arlington, TX 76015 | Oil & Gas Operator | Jul 2025 |
| 338 | Premier Natural Resources II,LLC | Tulsa, OK 74105 | Oil & Gas Operator | Feb 2015 |
| 339 | Premium Exploration Company | Early, TX 76803 | Oil & Gas Operator | Jul 2025 |
| 340 | Preston Exploration LLC | Spring, TX 77387 | Oil & Gas Operator | Dec 2014 |
| 341 | Prime Operating Company | Houston, TX 77024 | Oil & Gas Operator | Jul 2025 |
| 342 | Prize Operating Company | Grapevine, TX 76051 | Oil & Gas Operator | Aug 2016 |
| 343 | Proline Energy Resources Inc | Sugar Land, TX 77479 | Oil & Gas Operator | Jul 2025 |
| 344 | Prospctv Invstmnt & TRDG Co, LTD | Tulsa, OK 74170 | Oil & Gas Operator | May 2001 |
| 345 | Prosper Oil & Gas,Inc. | Dallas, TX 75201 | Oil & Gas Operator | Jul 2025 |
| 346 | Proven Natural Resources LLC | Canton, TX 75103 | Oil & Gas Operator | Jul 2025 |
| 347 | Pyramid Oil Of America, Inc. | Nichols Hill, OK 73116 | Oil & Gas Operator | Apr 2025 |
| 348 | Quantum Oil & Gas Corporation | Oklahoma City, OK 73172 | Oil & Gas Operator | Jul 2025 |
| 349 | Ramtex Energy LLC | Tulsa, OK 74114 | Oil & Gas Operator | Jul 2025 |
| 350 | Range Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2021 |
| 351 | Re-Op Corp. | Houston, TX 77274 | Oil & Gas Operator | Jul 2025 |
| 352 | Red Willow Production, LLC | Ignacio, CO 81137 | Oil & Gas Operator | Oct 2015 |
| 353 | Republic Resources, LLC. | San Antonio, TX 78212 | Oil & Gas Operator | Jul 2025 |
| 354 | Reynolds Drilling Co., Inc. | Shreveport, LA 71105 | Oil & Gas Operator | Jul 2025 |
| 355 | RHC Energy (USA) LLC | Houston, TX 77027 | Oil Operator | Jul 2025 |
| 356 | Ricks Expl Acquisition Corp | Oklahoma City, OK 73102 | Oil & Gas Operator | Jan 2004 |
| 357 | Ricks Expl Acquisition LLC | Midland, TX 79701 | Oil & Gas Operator | Aug 2013 |
| 358 | Ridge Petroleum Inc. | Tyler, TX 75701 | Oil & Gas Operator | Jul 2025 |
| 359 | Ridley Oil Corporation | Tyler, TX 75702 | Oil & Gas Operator | Nov 1996 |
| 360 | Riley Exploration, LLC | Blanchard, OK 73010 | Oil & Gas Operator | Jul 2025 |
| 361 | Rippy Oil Company | Tyler, TX 75702 | Oil & Gas Operator | Jul 2025 |
| 362 | Rise Petroleum Investments LLC | Tomball, TX 77377 | Oil & Gas Operator | Jul 2025 |
| 363 | River City Resources Inc | Tulsa, OK 74119 | Oil & Gas Operator | Nov 1997 |
| 364 | Rivershore Operating LLC | Dallas, TX 75206 | Oil & Gas Operator | Jul 2025 |
| 365 | Rme Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Nov 2016 |
| 366 | Robbins Energy, Inc. | Longview, TX 75606 | Oil & Gas Operator | Sep 1994 |
| 367 | Roberts & Hammack, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Jul 2025 |
| 368 | Rockefeller Hughes (USA) LLC | Houston, TX 77027 | Oil & Gas Operator | Jul 2015 |
| 369 | Rodessa Operating Company | Corpus Chrsti, TX 78426 | Oil & Gas Operator | Jul 2025 |
| 370 | Roosth & Genecov Production Co. | Tyler, TX 75710 | Oil & Gas Operator | Aug 2003 |
| 371 | Roosth Production Co. | Tyler, TX 75711 | Oil & Gas Operator | Jul 2025 |
| 372 | Rose City Resources, LLC | Tyler, TX 75703 | Oil & Gas Operator | Jul 2025 |
| 373 | Roy Jackson Energy Operating, LLC | Midland, TX 79701 | Oil & Gas Operator | Jul 2025 |
| 374 | RRCH Corp. | Longview, TX 75606 | Oil & Gas Operator | Dec 2013 |
| 375 | Rusk Energy Operating LLC | Houston, TX 77040 | Oil & Gas Operator | Jul 2025 |
| 376 | Rwa, LLC | Boyd, TX 76023 | Oil & Gas Operator | Jul 2025 |
| 377 | Sabine Oil & Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Jul 2025 |
| 378 | Samson Exploration LLC | Tulsa, OK 74101 | Oil & Gas Operator | May 2025 |
| 379 | Samson Hydrocarbons Company | Tulsa, OK 74103 | Oil & Gas Operator | Nov 2016 |
| 380 | Samson Lone Star LP | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2007 |
| 381 | Samson Lone Star, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Jul 2025 |
| 382 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2025 |
| 383 | Sandel Energy, Inc. | Huntsville, TX 77342 | Oil & Gas Operator | Apr 2004 |
| 384 | Sandel Operating Company | Huntsville, TX 77340 | Oil & Gas Operator | Jul 2025 |
| 385 | Sanhall Corporation | Huntsville, TX 77340 | Oil & Gas Operator | Oct 1993 |
| 386 | Saxet Operating Co.,Inc. | Madisonville, TX 77864 | Oil & Gas Operator | Jul 2025 |
| 387 | Scythian, LTD. | Midland, TX 79701 | Oil & Gas Operator | Dec 2020 |
| 388 | SDG Operating Company, Inc | Tyler, TX 75701 | Oil & Gas Operator | Jul 2025 |
| 389 | Seagull Energy E & P Inc | Houston, TX 77002 | Oil & Gas Operator | Jan 2015 |
| 390 | Senora Resources, Inc. | Dime Box, TX 77853 | Oil & Gas Operator | Jul 2025 |
| 391 | Shell Western E&P Inc. | Houston, TX 77001 | Oil & Gas Operator | May 2011 |
| 392 | Shoco Production, L.P. | Kilgore, TX 75663 | Oil & Gas Operator | May 2020 |
| 393 | Showhorn Holding Co., L.L.C. | Normangee, TX 77871 | Oil Operator | Jul 2025 |
| 394 | Shubuta Oil Corporation | Houston, TX 77056 | Oil & Gas Operator | Sep 1998 |
| 395 | Sikes Operating, Inc. | Tyler, TX 75711 | Oil & Gas Operator | Jun 2003 |
| 396 | Sinclair Oil & Gas Company | Salt Lake Cty, UT 84130 | Oil & Gas Operator | Jul 2025 |
| 397 | Sklar Exploration Company LLC | Shreveport, LA 71101 | Oil & Gas Operator | Jul 2025 |
| 398 | Smith Oil Company | Smackover, AR 71762 | Oil Operator | Dec 2024 |
| 399 | Smith Petroleum Company | Spring, TX 77389 | Oil & Gas Operator | Jul 2025 |
| 400 | SND Operating, L.L.C. | Kilgore, TX 75663 | Oil & Gas Operator | Jul 2025 |