| 301 | St. Paul Oil And Gas Corp. | | Oil & Gas Operator | Aug 1991 |
| 302 | Stallion Oil Corporation | | Oil & Gas Operator | Nov 1987 |
| 303 | Stanco Petroleum Inc | Kimball, NE 69145 | Oil & Gas Operator | Jul 1999 |
| 304 | Standard Operating Company, LLC | | Oil & Gas Operator | May 2022 |
| 305 | Standard Production | | Oil Operator | Oct 1997 |
| 306 | Star Energy Inc | Dayton, PA 16222-4325 | Oil & Gas Operator | Dec 2025 |
| 307 | Star Falcon Oil Co. | | Oil Operator | Feb 1986 |
| 308 | Star Oil & Gas, Inc. | | Oil & Gas Operator | Sep 1995 |
| 309 | State Energy & Investment Inc. | | Oil & Gas Operator | Mar 1990 |
| 310 | State Line Vacuum Services, LLC | | Oil Operator | Mar 2021 |
| 311 | Statex Petroleum Inc | Dallas, TX 75229 | Oil & Gas Operator | Dec 2000 |
| 312 | Statoil Exploration (Us) Inc. | | Oil & Gas Operator | Jul 1997 |
| 313 | Steaua Romana (Us) Inc. | | Oil & Gas Operator | Apr 1987 |
| 314 | Stenco | | Oil & Gas Operator | Apr 1994 |
| 315 | Stephens & Johnson Operating Co. | Wichita Falls, TX 76307 | Oil & Gas Operator | Feb 2026 |
| 316 | Stephens Production Company | The Woodlands, TX 77381 | Oil & Gas Operator | Dec 2025 |
| 317 | Sterlington Memorial Hospital | | Gas Operator | Jan 2005 |
| 318 | Stetson Petroleum Corp. | Rollins, MT 59931 | Oil & Gas Operator | Feb 2026 |
| 319 | Steveco | | Oil Operator | Feb 1984 |
| 320 | Stewart Oil Co. | | Oil Operator | Jun 2009 |
| 321 | Stinhall Corporation | | Oil & Gas Operator | Apr 1989 |
| 322 | Stinson Gas Company, L.L.C. | | Gas Operator | Jul 2018 |
| 323 | Stone Energy Corporation | Denver, CO 80202-2828 | Oil & Gas Operator | Oct 2014 |
| 324 | Stone Oil Corp & McMoran Expl | | Oil & Gas Operator | Oct 1984 |
| 325 | Stone Oil Corp - Strata Energy | | Oil & Gas Operator | Mar 1982 |
| 326 | Stone Oil Corp-Forest Oil Corp | | Oil & Gas Operator | Jan 1983 |
| 327 | Stone Oil-Lamson-Onshore Pet. | | Oil & Gas Operator | May 1985 |
| 328 | Stone Oil-Quasar-Birthright | | Oil & Gas Operator | Feb 1981 |
| 329 | Stone Petroleum Corporation | | Oil & Gas Operator | Dec 1996 |
| 330 | Story Oil And Gas Inc | Magnolia, AR 71753 | Oil & Gas Operator | Jan 2025 |
| 331 | Strago Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Aug 1994 |
| 332 | Strahan Oil & Gas Co., Inc. | | Gas Operator | Oct 1983 |
| 333 | Strand Energy, L.C. | Houston, TX 77002 | Oil & Gas Operator | Feb 2026 |
| 334 | Strat Land Exploration Company | Tulsa, OK 74103 | Oil & Gas Operator | Nov 2025 |
| 335 | Strata Energy, Inc. | | Oil & Gas Operator | Sep 1983 |
| 336 | Strataform, Inc. | | Gas Operator | Jun 2002 |
| 337 | Stratco Operating Co Inc | Austin, TX 78701 | Oil & Gas Operator | Feb 2026 |
| 338 | Strike Energy Corporation | Blackwell, OK 74631 | Oil & Gas Operator | Jul 2023 |
| 339 | Striker Petroleum Corporation | Englewood, CO 80111 | Oil & Gas Operator | Dec 1999 |
| 340 | Striper Oil, Inc. | Dallas, TX 75379 | Oil & Gas Operator | Apr 2002 |
| 341 | Stroud Operating LLC | | Oil & Gas Operator | Dec 2012 |
| 342 | Stroud Petroleum, Inc. | Shreveport, LA 71162 | Oil & Gas Operator | Feb 2026 |
| 343 | Stroud Production LLC | Shreveport, LA 71101 | Oil & Gas Operator | Dec 2024 |
| 344 | STS Petroleum LLC | Houston, TX 77289 | Oil & Gas Operator | Feb 2026 |
| 345 | Stuart Oil | | Oil Operator | Jan 2025 |
| 346 | Studley Resources Corporation | Humble, TX 77347 | Oil & Gas Operator | Dec 1996 |
| 347 | Sturlese-Dupre Exploration Co | | Oil & Gas Operator | Aug 1994 |
| 348 | STZ Petroleum Inc. | Houston, TX 77268 | Oil & Gas Operator | Dec 1997 |
| 349 | Subsurface Resources Inc | Logan, UT 84321 | Oil & Gas Operator | Aug 1990 |
| 350 | Suburban Prop Corp. & May Pet. | | Gas Operator | Oct 1980 |
| 351 | Suburban Propane Expl Co, Inc. | | Oil & Gas Operator | Jun 1983 |
| 352 | Suburban Propane Gas Corp. | | Oil & Gas Operator | Sep 1980 |
| 353 | Sue-Ann Operating, L.C. | Victoria, TX 77903 | Oil & Gas Operator | Feb 2026 |
| 354 | Sugar Bowl Gas Corp. | | Oil Operator | Dec 1983 |
| 355 | Sugar Bowl Industrial Gas Corp | | Oil Operator | Dec 1983 |
| 356 | Sugar Creek Environmental, LLC | | Oil Operator | Jan 2025 |
| 357 | Sugar Creek Producing Company | | Oil & Gas Operator | Dec 2010 |
| 358 | Sugar Creek Producing Company, LLC | | Oil & Gas Operator | Jan 2025 |
| 359 | Sugar Oil Company | | Oil & Gas Operator | Feb 2011 |
| 360 | Sullivan Well Service | | Oil Operator | Mar 2010 |
| 361 | Sulphur River Exploration, Inc. | Dallas, TX 75244 | Oil & Gas Operator | Feb 2026 |
| 362 | Summit Energy Company | | Oil & Gas Operator | Mar 2009 |
| 363 | Summit Energy,Inc | Littleton, CO 80127 | Oil & Gas Operator | Aug 2013 |
| 364 | Summit Gas LLC | | Oil & Gas Operator | Oct 2011 |
| 365 | Summit Oil & Gas, LLC | | Oil & Gas Operator | Nov 2024 |
| 366 | Summit Operating LLC | Boulder, CO 80301 | Oil & Gas Operator | Nov 2025 |
| 367 | Summit Overseas Expl., Inc. | Denver, CO 80226 | Oil & Gas Operator | Apr 2007 |
| 368 | Summit Resources, Inc. | Houston, TX 77077 | Oil & Gas Operator | Sep 2016 |
| 369 | Sun Exploration And Production Co | | Oil & Gas Operator | Jan 1990 |
| 370 | Sun Resources Texas, Inc. | Longview, TX 75606 | Oil & Gas Operator | Dec 2024 |
| 371 | Sun Texas Company | | Oil & Gas Operator | Jun 1981 |
| 372 | Sunburst, Inc. | Wheat Ridge, CO 80033 | Oil & Gas Operator | Dec 2025 |
| 373 | Sunchase Exploration, Inc. | | Oil & Gas Operator | Oct 1997 |
| 374 | Suncoast Investments Co., Inc. | Plano, TX 75074 | Oil & Gas Operator | Oct 2001 |
| 375 | Suncoast Technical SVCS., Inc. | | Oil & Gas Operator | Dec 2011 |
| 376 | Sundance Energy Corporation | | Oil & Gas Operator | Jan 2025 |
| 377 | Sundown Energy LP | Dallas, TX 75248 | Oil & Gas Operator | Feb 2026 |
| 378 | Sundown Energy, Inc. | Dallas, TX 75240 | Oil & Gas Operator | May 2025 |
| 379 | Sunex Production, Inc. | | Gas Operator | Mar 1988 |
| 380 | Sunex Resources Incorporated | | Oil Operator | Dec 1981 |
| 381 | Sunland Production Company, Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Dec 2025 |
| 382 | Super Energy Inc. | | Oil & Gas Operator | Oct 1993 |
| 383 | Superior - Austral | | Oil & Gas Operator | Mar 1978 |
| 384 | Superior Oil Co. | Denver, CO 80217-5444 | Oil & Gas Operator | Feb 2001 |
| 385 | Superior Operating LLC | | Oil Operator | May 2020 |
| 386 | Superior Resources Corporation | | Oil Operator | Apr 2006 |
| 387 | Superior-American Quasar | | Oil & Gas Operator | Jan 1981 |
| 388 | Superior-Tenneco | | Oil & Gas Operator | Jun 1982 |
| 389 | Sutton Joint Account | | Oil Operator | Mar 1988 |
| 390 | Sutton-Gerard Et Al | | Oil & Gas Operator | Jan 1990 |
| 391 | Sutton-Gerard-Sawyer | | Oil & Gas Operator | Jan 1990 |
| 392 | Sutton-Sawyer | | Oil Operator | Mar 1989 |
| 393 | SV Energy Company, LLC | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Mar 2017 |
| 394 | SW Associates | | Oil & Gas Operator | Dec 1985 |
| 395 | Swag Oil And Gas Company, Inc. | | Oil & Gas Operator | Jul 1982 |
| 396 | Swampfox Oilfield Services, LLC | | Oil & Gas Operator | Dec 2024 |
| 397 | Swan Lake Properties, Inc. | | Oil Operator | Jul 1987 |
| 398 | SWD Acidizing, Inc. | | Oil Operator | Feb 2014 |
| 399 | SWD, Inc. | | Oil Operator | Jan 2025 |
| 400 | Swepi LP | Houston, TX 77079 | Oil & Gas Operator | Jul 2020 |