| 301 | Pilot Resources, Inc. | | Oil & Gas Operator | May 2013 |
| 302 | Pioneer Exploration Company | Houston, TX 77090 | Oil & Gas Operator | Jan 2025 |
| 303 | Pioneer Exploration, LLC | Houston, TX 77090 | Oil & Gas Operator | Dec 2024 |
| 304 | Pioneer Exploration, LTD. | Houston, TX 77090 | Oil & Gas Operator | Sep 2008 |
| 305 | Pioneer Prod. Corp. | | Oil & Gas Operator | Jun 1986 |
| 306 | Plains Resources Inc. | Houston, TX 77002 | Oil & Gas Operator | Jul 2008 |
| 307 | Plano Corp. | | Oil & Gas Operator | Mar 2005 |
| 308 | Plymouth Resources Group II Inc | | Oil & Gas Operator | May 2007 |
| 309 | Pogo Producing Company | Houston, TX 77002 | Oil & Gas Operator | Jan 2008 |
| 310 | Polaris Enterprises Inc | Houston, TX 77057 | Oil & Gas Operator | Oct 1998 |
| 311 | Power Reserves, Inc. | | Oil Operator | Feb 1999 |
| 312 | Prairie Producing Company | | Oil & Gas Operator | Dec 1992 |
| 313 | Prayer Oil & Gas Production, LLC | Hallsville, TX 75650 | Oil & Gas Operator | Mar 2025 |
| 314 | Premience Energy LLC | | Oil & Gas Operator | Dec 2024 |
| 315 | Presidio Exploration, Inc. | Englewood, CO 80155 | Oil & Gas Operator | May 1999 |
| 316 | Puma, Inc. | | Oil & Gas Operator | Oct 2000 |
| 317 | PXP Gulf Coast Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 318 | PXP Louisiana L.L.C. | | Oil & Gas Operator | Nov 2010 |
| 319 | Quantum Resources MGMT, LLC | | Oil & Gas Operator | Nov 2014 |
| 320 | Quest Exploration L.L.C. | | Oil & Gas Operator | Jul 2014 |
| 321 | Quintana Petroleum Corporation | Denver, CO 80265 | Oil & Gas Operator | Mar 1998 |
| 322 | R360 Environmental Solutions Of La, LLC | | Oil Operator | Jan 2025 |
| 323 | Reef Exploration Inc | Denver, CO 80202 | Oil & Gas Operator | Feb 2007 |
| 324 | Riceland Petroleum Company | | Oil & Gas Operator | Nov 2024 |
| 325 | Richardson Energy Corporation | | Oil & Gas Operator | Dec 1987 |
| 326 | Rio Bravo Oil Company | The Woodlands, TX 77381 | Oil & Gas Operator | Feb 2002 |
| 327 | Riseden Services, Inc. | Houston, TX 77256 | Oil & Gas Operator | Sep 1997 |
| 328 | Riseden, LTD | | Oil & Gas Operator | Nov 1989 |
| 329 | Robertson Energy, LLC | | Oil & Gas Operator | Dec 2024 |
| 330 | Rock Creek Oil, Inc. | Dallas, TX 75225 | Oil & Gas Operator | Nov 2019 |
| 331 | Rockleigh K. Thurman | | Oil & Gas Operator | Jan 2025 |
| 332 | Rodessa Operating Company | Corpus Chrsti, TX 78426 | Oil & Gas Operator | Mar 2025 |
| 333 | Rogers Oil Co. | Bronson, KS 66716 | Oil & Gas Operator | Sep 1995 |
| 334 | Rosewood Resources (Poc), Inc. | | Oil & Gas Operator | Dec 1984 |
| 335 | Rosewood Resources, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Mar 2025 |
| 336 | Royal Production Company, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Mar 2025 |
| 337 | RPS Energy, Inc. | | Oil & Gas Operator | Jul 2020 |
| 338 | S&B Petroleum Corporation | | Oil & Gas Operator | Jun 1994 |
| 339 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2024 |
| 340 | Sandefer Petroleum Co. | | Oil & Gas Operator | Apr 1994 |
| 341 | Sandhill Production Inc | Shongaloo, LA 71072 | Oil & Gas Operator | Dec 2019 |
| 342 | Santa Fe Braun, Inc | Dallas, TX 75240-6620 | Oil & Gas Operator | Mar 1995 |
| 343 | Santa Fe Energy Operg Parts LP | | Oil & Gas Operator | Nov 1993 |
| 344 | Santa Fe Energy Resources, Inc. | Houston, TX 77024 | Oil & Gas Operator | Mar 2008 |
| 345 | Se USA Operating, Inc. | Houston, TX 77002 | Oil & Gas Operator | Dec 2009 |
| 346 | Senior G&A Operating Co Inc | | Oil & Gas Operator | Nov 1991 |
| 347 | Shell Oil Company | Houston, TX 77210 | Oil & Gas Operator | Apr 2015 |
| 348 | Shell Western E&P Inc. | Houston, TX 77001 | Oil & Gas Operator | May 2011 |
| 349 | Shore Oil Company | | Oil & Gas Operator | May 1998 |
| 350 | Shoreline Southeast LLC | | Oil & Gas Operator | Jun 2017 |
| 351 | Smith Petroleum Company | Spring, TX 77389 | Oil & Gas Operator | Mar 2025 |
| 352 | Smith Production Co. | Wichita Falls, TX 76308 | Oil & Gas Operator | Mar 2025 |
| 353 | Sohio Petroleum Co. | Casper, WY 82602 | Oil & Gas Operator | Apr 1986 |
| 354 | Sohio Petroleum Co. Et Al | | Oil & Gas Operator | May 1979 |
| 355 | Sonat Exploration Co. | Houston, TX 77251 | Oil & Gas Operator | Dec 2021 |
| 356 | Source Petroleum Inc. | San Antonio, TX 78265 | Oil & Gas Operator | Mar 2025 |
| 357 | South Oak Production Company | | Oil & Gas Operator | Jun 2010 |
| 358 | Southern G Holdings, LLC | Houston, TX 77002 | Oil & Gas Operator | Dec 2007 |
| 359 | Southern Production & Expl Co. | | Oil & Gas Operator | Apr 2008 |
| 360 | Southwest Oil Properties, Inc. | | Oil & Gas Operator | Feb 1996 |
| 361 | Square Mile Energy, L.L.C. | Houston, TX 77057 | Oil & Gas Operator | Mar 2025 |
| 362 | St. Mary Energy Company | Houston, TX 77079 | Oil & Gas Operator | Aug 2008 |
| 363 | St. Mary Land & Exploration Co | Denver, CO 80201 | Oil & Gas Operator | Jun 2010 |
| 364 | Stone Oil Corp - Strata Energy | | Oil & Gas Operator | Mar 1982 |
| 365 | Stone Petroleum Corporation | | Oil & Gas Operator | Dec 1996 |
| 366 | Sun Exploration-Production Co. | | Oil & Gas Operator | Jan 1990 |
| 367 | Sun Texas Company | | Oil & Gas Operator | Jun 1981 |
| 368 | Superior Oil Co. | Denver, CO 80217-5444 | Oil & Gas Operator | Feb 2001 |
| 369 | SWD, Inc. | | Oil Operator | Jan 2025 |
| 370 | Synergy Oil & Gas, L.P. | Houston, TX 77024 | Oil & Gas Operator | May 2012 |
| 371 | T & B Resources | | Oil & Gas Operator | Jul 1990 |
| 372 | Tabco Exploration Inc. | New Orleans, LA 70131 | Oil & Gas Operator | Dec 1998 |
| 373 | Targa Midstream Services LLC | Houston, TX 77002 | Oil Operator | Mar 2023 |
| 374 | Tarpon Oil Of Texas | | Oil & Gas Operator | Aug 1994 |
| 375 | Tee Operating Company | | Oil & Gas Operator | Jun 1989 |
| 376 | Telico Minerals, L.L.C. | | Oil & Gas Operator | Oct 2019 |
| 377 | Tenneco Oil Company | Oklahoma City, OK 73125 | Oil & Gas Operator | Dec 2024 |
| 378 | Tennessee Gas Pipeline Company | Houston, TX 77252 | Oil & Gas Operator | Dec 2011 |
| 379 | Tennessee Gas Pipeline Company, LLC | Houston, TX 77252 | Oil Operator | Dec 2024 |
| 380 | Tensas Exploraton & Production Co LLC | | Oil & Gas Operator | Nov 2009 |
| 381 | Tesla Resources, Inc. | | Oil & Gas Operator | Aug 1996 |
| 382 | Tex/Con Oil & Gas Company | Houston, TX 77074 | Oil & Gas Operator | Feb 2001 |
| 383 | Texaco Inc | Kingfisher, OK 73750 | Oil & Gas Operator | Dec 2017 |
| 384 | Texaco Producing Inc. | Rock Springs, WY 82901 | Oil & Gas Operator | Dec 2000 |
| 385 | Texas Gas Exploration Corp. | | Oil & Gas Operator | Nov 1986 |
| 386 | Texas Pacific Oil Company Inc. | | Oil & Gas Operator | Dec 1980 |
| 387 | Texas Petroleum Investment Company | Houston, TX 77057 | Oil & Gas Operator | Mar 2025 |
| 388 | Texasgulf Inc. | Newgulf, TX 77462 | Oil & Gas Operator | Jul 1994 |
| 389 | The Ballard & Cordell Corp | | Oil & Gas Operator | Feb 1982 |
| 390 | The Meridian Res. & Exp. LLC | | Oil & Gas Operator | Sep 2010 |
| 391 | The Meridian Resource & Exp Co | | Oil & Gas Operator | Dec 2000 |
| 392 | The Southern Louisiana Expl. Company LLC | | Oil & Gas Operator | Nov 2024 |
| 393 | Thomas C. Hoffpauir | | Oil & Gas Operator | Mar 1991 |
| 394 | Tiger Petroleum | | Oil Operator | Sep 2002 |
| 395 | Tipco | Shreveport, LA 71104-3047 | Oil & Gas Operator | May 1988 |
| 396 | Tom Brown Inc | Denver, CO 80202 | Oil & Gas Operator | Dec 2004 |
| 397 | Tom Littlepage Oil Properties | | Oil & Gas Operator | Dec 1984 |
| 398 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 399 | Total Minatome Corporation | Houston, TX 77210 | Oil & Gas Operator | Dec 1998 |
| 400 | Trace Operators, Inc. | | Oil & Gas Operator | Nov 2024 |