| 301 | Northern Michigan Expl Co | | Oil & Gas Operator | Jul 1990 |
| 302 | O'Sullivan Oil & Gas Co., Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2000 |
| 303 | Ocean Energy Inc | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 304 | Ody Oil Corp. | | Oil & Gas Operator | Oct 1994 |
| 305 | Oil & Gas Property MGMT., Inc. | Dallas, TX 75201 | Oil & Gas Operator | Jul 1996 |
| 306 | Opmi Operating Company | Houston, TX 77057 | Oil & Gas Operator | Jun 2008 |
| 307 | Orx Resources, L.L.C. | Houston, TX 77067 | Oil & Gas Operator | Dec 2025 |
| 308 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 309 | P & P Producing Inc | Midland, TX 79702 | Oil & Gas Operator | Feb 2015 |
| 310 | Pacific Enterprises Oil Co USA | Dallas, TX 75201 | Oil & Gas Operator | Feb 2001 |
| 311 | Palace Operating Company | Tulsa, OK 74136 | Oil & Gas Operator | Aug 2009 |
| 312 | Paragon Resources, Inc | | Oil & Gas Operator | Nov 1991 |
| 313 | Parker & Parsley Development Co. | Midland, TX 79702 | Oil & Gas Operator | May 1995 |
| 314 | Parker & Parsley Devpt L P | | Oil & Gas Operator | Oct 1997 |
| 315 | Parker & Parsley Petroleum Co. | | Oil & Gas Operator | Dec 1990 |
| 316 | Partners Oil Company | Tulsa, OK 74135 | Oil & Gas Operator | Aug 1995 |
| 317 | Pel-Tex - McMoran | | Oil & Gas Operator | Dec 1985 |
| 318 | Pel-Tex Oil Company, Inc. | | Oil & Gas Operator | Jul 1995 |
| 319 | Pel-Tex, Inc. | | Oil & Gas Operator | Jul 1985 |
| 320 | Penn Resources, Inc. | Dallas, TX 75219 | Oil & Gas Operator | Sep 1987 |
| 321 | Pennzoil E & P Co - Arco | | Oil & Gas Operator | Dec 1993 |
| 322 | Pennzoil E & P Co Et Al | | Oil & Gas Operator | Feb 1999 |
| 323 | Pennzoil Exploration & Production Co. | Carthage, TX 75633 | Oil & Gas Operator | Mar 2008 |
| 324 | Petro-Hunt, L.L.C. | Dallas, TX 75201 | Oil & Gas Operator | Dec 2025 |
| 325 | Petro-Lewis Corp. | | Oil & Gas Operator | Feb 1994 |
| 326 | Petrodome Operating, LLC | Houston, TX 77265 | Oil & Gas Operator | Jun 2025 |
| 327 | Petroquest Energy, Inc. | Lafayette, LA 70505 | Oil & Gas Operator | Feb 2001 |
| 328 | Petroquest Energy, L.L.C. | Lafayette, LA 70505 | Oil & Gas Operator | Dec 2025 |
| 329 | Petsec Energy Inc. | | Oil & Gas Operator | Sep 2012 |
| 330 | PG&E Resources Company | Houston, TX 77042 | Oil & Gas Operator | May 1995 |
| 331 | Phillips Oil Company | Casper, WY 82602 | Oil & Gas Operator | Sep 1986 |
| 332 | Phillips Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Mar 2013 |
| 333 | Phoenix Exploration Company LP | | Oil & Gas Operator | Sep 2011 |
| 334 | Phoenix Oil & Gas LTD., L.L.P. | Houston, TX 77010 | Oil & Gas Operator | Jun 2004 |
| 335 | Pilot Resources, Inc. | | Oil & Gas Operator | May 2013 |
| 336 | Pioneer Natural Resources USA Inc | Irving, TX 75039 | Oil & Gas Operator | Jun 2025 |
| 337 | Placid Oil Co., Et Al | | Oil & Gas Operator | Jun 1983 |
| 338 | Placid Oil Company | Houston, TX 77227 | Oil & Gas Operator | Mar 2008 |
| 339 | Plains Resources Inc. | Houston, TX 77002 | Oil & Gas Operator | Jul 2008 |
| 340 | Prentice Oil & Gas Company | | Oil & Gas Operator | Nov 1982 |
| 341 | Primary Fuels Inc | Midland, TX 79701-4410 | Oil & Gas Operator | Mar 1991 |
| 342 | Prize Operating Company | Grapevine, TX 76051 | Oil & Gas Operator | Aug 2016 |
| 343 | Production Gauging Service Inc | | Oil Operator | Feb 1999 |
| 344 | Production Management Corp. | | Oil & Gas Operator | Jul 1987 |
| 345 | Prospera Energy, Inc. | | Oil & Gas Operator | Dec 2005 |
| 346 | Proven Fuel Exploration, Inc. | | Oil & Gas Operator | Mar 2022 |
| 347 | Pure Resources, L.P. | Midland, TX 79701 | Oil & Gas Operator | Mar 2006 |
| 348 | Quintana Petroleum Corporation | Denver, CO 80265 | Oil & Gas Operator | Mar 1998 |
| 349 | Quintana Production Co. | | Oil & Gas Operator | Feb 1987 |
| 350 | R & B Oil Company, LLC Of Texas | | Oil & Gas Operator | Jan 2025 |
| 351 | Range Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2021 |
| 352 | Rapiere Resources Company | | Oil & Gas Operator | Aug 2024 |
| 353 | Renaissance Petroleum Co LLC | Houston, TX 77058 | Oil & Gas Operator | Nov 2011 |
| 354 | Reserve Oil Inc. | | Oil & Gas Operator | Jan 1980 |
| 355 | Rio Bravo Oil Company | The Woodlands, TX 77381 | Oil & Gas Operator | Feb 2002 |
| 356 | Rme Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Nov 2016 |
| 357 | Rockleigh K. Thurman | | Oil & Gas Operator | Jan 2025 |
| 358 | Rosewood Resources (Poc), Inc. | | Oil & Gas Operator | Dec 1984 |
| 359 | Rosewood Resources Inc | Dallas, TX 75201 | Oil & Gas Operator | Dec 2025 |
| 360 | Rowe Oil And Gas, Inc. | | Oil & Gas Operator | Jun 1999 |
| 361 | Royal Production Company, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Dec 2025 |
| 362 | S2 Energy 1, LP | | Oil & Gas Operator | Nov 2012 |
| 363 | S2 Energy Operating LLC | | Oil & Gas Operator | May 2023 |
| 364 | Samson Contour Energy E&P, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Sep 2017 |
| 365 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Aug 2025 |
| 366 | Sanare Energy Partners, LLC | | Oil & Gas Operator | Dec 2024 |
| 367 | Sandefer Petroleum Co. | | Oil & Gas Operator | Apr 1994 |
| 368 | Sante Fe Minerals | | Oil & Gas Operator | Dec 1987 |
| 369 | Senior G&A Operating Co Inc | | Oil & Gas Operator | Nov 1991 |
| 370 | Shell Offshore Inc. | New Orleans, LA 70161 | Oil & Gas Operator | Jan 2008 |
| 371 | Shell Oil Co. | Houston, TX 77001 | Oil & Gas Operator | Jun 1985 |
| 372 | Shell Western E&P Inc. | Houston, TX 77001 | Oil & Gas Operator | May 2011 |
| 373 | Shoreline Southeast LLC | | Oil & Gas Operator | Jun 2017 |
| 374 | Signal Petroleum | | Oil & Gas Operator | Jul 1980 |
| 375 | Singer-Fleischaker Oil Co Inc | | Oil & Gas Operator | Jul 1987 |
| 376 | Skelly Oil Co | | Oil & Gas Operator | Mar 2005 |
| 377 | SMC Oil & Gas, Inc. | Midland, TX 79710 | Oil & Gas Operator | Dec 2025 |
| 378 | Smith Production Co. | Wichita Falls, TX 76308 | Oil & Gas Operator | Dec 2025 |
| 379 | Sohio Petroleum Co. | Casper, WY 82602 | Oil & Gas Operator | Apr 1986 |
| 380 | Sonat Exploration Co. | Houston, TX 77251 | Oil & Gas Operator | Dec 2021 |
| 381 | Source Petroleum Inc. | San Antonio, TX 78265 | Oil & Gas Operator | Dec 2025 |
| 382 | South La. Production Co., Inc. | | Oil & Gas Operator | Jun 1982 |
| 383 | South Oak Production Company | | Oil & Gas Operator | Jun 2010 |
| 384 | Southern Bay Operating, L.L.C. | Houston, TX 77002 | Oil & Gas Operator | Jun 2013 |
| 385 | Southern Natural Gas Co | Houston, TX 77001 | Oil & Gas Operator | Dec 2011 |
| 386 | Southport Exploration Inc | Tulsa, OK 74103-4015 | Oil & Gas Operator | Nov 1998 |
| 387 | Southwestern Energy Prod Co | Houston, TX 77032 | Oil & Gas Operator | Jun 2015 |
| 388 | Square Mile Energy, L.L.C. | Houston, TX 77057 | Oil & Gas Operator | Dec 2025 |
| 389 | SRP Production Corp. | | Oil & Gas Operator | Nov 1997 |
| 390 | St. Mary Land & Exploration Co | Denver, CO 80201 | Oil & Gas Operator | Jun 2010 |
| 391 | Star Oil & Gas, Inc. | | Oil & Gas Operator | Sep 1995 |
| 392 | Stone Energy Corporation | Denver, CO 80202-2828 | Oil & Gas Operator | Oct 2014 |
| 393 | Stone Petroleum Corporation | | Oil & Gas Operator | Dec 1996 |
| 394 | Stratco Operating Co Inc | Austin, TX 78701 | Oil & Gas Operator | Dec 2025 |
| 395 | Sugar Bowl Industrial Gas Corp | | Oil Operator | Dec 1983 |
| 396 | Sulphur River Exploration, Inc. | Dallas, TX 75244 | Oil & Gas Operator | Dec 2025 |
| 397 | Sun Exploration And Production Co | | Oil & Gas Operator | Jan 1990 |
| 398 | Superior Oil Co. | Denver, CO 80217-5444 | Oil & Gas Operator | Feb 2001 |
| 399 | Superior-Tenneco | | Oil & Gas Operator | Jun 1982 |
| 400 | Talos Energy Offshore LLC | | Oil & Gas Operator | Jan 2025 |