| 201 | Smith Oil And Gas Co | Wichita Falls, TX 76310 | Oil Operator | Dec 2010 |
| 202 | Smith Operating And MGMT Co. | Shreveport, LA 71161 | Oil & Gas Operator | Jun 2023 |
| 203 | Smith Operating-Germany Oil | | Oil & Gas Operator | Dec 1995 |
| 204 | Smith Petroleum Company | Spring, TX 77389 | Oil & Gas Operator | Feb 2026 |
| 205 | Smith Production Co. | Wichita Falls, TX 76308 | Oil & Gas Operator | Feb 2026 |
| 206 | Smith-Wentworth | | Oil & Gas Operator | Sep 1983 |
| 207 | Smith-Wentworth & Coquina | | Oil Operator | Jun 1983 |
| 208 | Smith-Wentworth & Hughes & New | | Oil Operator | Jun 1983 |
| 209 | SMK-La, Inc. | | Oil & Gas Operator | Sep 1999 |
| 210 | SMR Natural Gas Ventures Inc | Oklahoma City, OK 73112 | Oil & Gas Operator | Jan 1999 |
| 211 | SND Operating, L.L.C. | Kilgore, TX 75663 | Oil & Gas Operator | Feb 2026 |
| 212 | Snyder Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2015 |
| 213 | Snyder Oil Corporation | Houston, TX 77024 | Oil & Gas Operator | Mar 2008 |
| 214 | Sohio Petr Co-Gulf Oil Corp | | Oil & Gas Operator | Dec 1979 |
| 215 | Sohio Petroleum Co. | Casper, WY 82602 | Oil & Gas Operator | Apr 1986 |
| 216 | Sohio Petroleum Co. Et Al | | Oil & Gas Operator | May 1979 |
| 217 | Sola Oil Company, Inc. | | Oil & Gas Operator | Aug 1991 |
| 218 | Sola Operating, LLC | Trout, LA 71371 | Oil Operator | Feb 2026 |
| 219 | Solatex | | Oil & Gas Operator | Oct 1978 |
| 220 | Solatex Resources, LTD | Houston, TX 77257 | Oil & Gas Operator | Feb 2026 |
| 221 | Soldier Operating LLC | | Oil & Gas Operator | Dec 2024 |
| 222 | Solid Rock Prod. | | Oil Operator | Nov 1994 |
| 223 | Son-Dad Oil & Gas | | Oil & Gas Operator | Dec 1994 |
| 224 | Sonat Exploration Co. | Houston, TX 77251 | Oil & Gas Operator | Dec 2021 |
| 225 | Sonat Exploration Gom Inc. | Houston, TX 77251 | Oil & Gas Operator | Dec 1999 |
| 226 | Sonny King | | Oil & Gas Operator | Jan 2025 |
| 227 | Sonny King Production | | Oil & Gas Operator | Jan 2025 |
| 228 | Sonora Producing, Inc. | | Oil & Gas Operator | May 2006 |
| 229 | Sonoran Energy Inc. | Addison, TX 75001 | Oil & Gas Operator | Feb 2026 |
| 230 | Sooner Corp | | Oil & Gas Operator | Oct 1990 |
| 231 | Sooner Resources, Inc. | | Oil & Gas Operator | Mar 1987 |
| 232 | Sotrana-Texas Corp. | | Oil & Gas Operator | Oct 1984 |
| 233 | Sound Resources Corporation | | Oil & Gas Operator | Dec 2003 |
| 234 | Source Petroleum Inc. | San Antonio, TX 78265 | Oil & Gas Operator | Feb 2026 |
| 235 | South Central Petroleum, Inc. | | Oil & Gas Operator | Dec 1988 |
| 236 | South Coast Oil, Inc. | | Oil & Gas Operator | Jul 1989 |
| 237 | South La. Production Co., Inc. | | Oil & Gas Operator | Jun 1982 |
| 238 | South Leeville, LLC | Houston, TX 77069 | Oil & Gas Operator | Oct 2022 |
| 239 | South Oak Production Company | | Oil & Gas Operator | Jun 2010 |
| 240 | South River Operating, LLC | | Oil & Gas Operator | Dec 2016 |
| 241 | Southampton Mineral Corp. | | Oil & Gas Operator | Aug 2005 |
| 242 | Southco Oil And Gas Inc. | | Oil & Gas Operator | Nov 2000 |
| 243 | Southeastern Public Service Co | | Oil & Gas Operator | Sep 1982 |
| 244 | Southern Bay Operating, L.L.C. | Houston, TX 77002 | Oil & Gas Operator | Jun 2013 |
| 245 | Southern G Holdings, LLC | Houston, TX 77002 | Oil & Gas Operator | Dec 2007 |
| 246 | Southern Management Services | | Oil Operator | May 2017 |
| 247 | Southern Natural Gas Co | Houston, TX 77001 | Oil & Gas Operator | Dec 2011 |
| 248 | Southern Natural Gas Company LLC | | Oil & Gas Operator | Nov 2024 |
| 249 | Southern Oil & Gas Company | | Oil & Gas Operator | Mar 2011 |
| 250 | Southern Oil Of Louisiana LLC | Madisonville, LA 70447 | Oil & Gas Operator | Feb 2026 |
| 251 | Southern Operating, Inc. | | Oil Operator | Dec 2000 |
| 252 | Southern Petroleum Company | | Oil & Gas Operator | Jan 1994 |
| 253 | Southern Production & Expl Co. | | Oil & Gas Operator | Apr 2008 |
| 254 | Southern Production Co Inc | Madill, OK 73446 | Oil & Gas Operator | Nov 2025 |
| 255 | Southern Production SVC., Inc. | | Oil Operator | Mar 1997 |
| 256 | Southern Solutions And Services LLC | | Oil Operator | Dec 2014 |
| 257 | Southern Star Operating, Inc. | | Oil & Gas Operator | Jun 2010 |
| 258 | Southern States Gas & Oil LTD | | Oil & Gas Operator | Jul 2004 |
| 259 | Southern States Oil Production, LLC | | Oil & Gas Operator | Oct 2013 |
| 260 | Southern States Petroleum Corp | | Oil Operator | Jan 1984 |
| 261 | Southern Union Exploration Co. | Austin, TX 78701 | Oil & Gas Operator | Feb 2002 |
| 262 | Southern Water Disposal, LLC | | Oil & Gas Operator | Jan 2025 |
| 263 | Southern Wells, Inc. | | Oil Operator | Sep 2002 |
| 264 | Southland Royalty Company | Houston, TX 77210 | Oil & Gas Operator | Sep 2011 |
| 265 | Southport Exploration Inc | Tulsa, OK 74103-4015 | Oil & Gas Operator | Nov 1998 |
| 266 | Southwest Gas Producing Co Inc | | Oil & Gas Operator | Nov 1994 |
| 267 | Southwest General Dev., Inc. | | Oil & Gas Operator | Dec 2003 |
| 268 | Southwest Ind Investment Co | | Gas Operator | Oct 1983 |
| 269 | Southwest Oil Properties, Inc. | | Oil & Gas Operator | Feb 1996 |
| 270 | Southwest Operating Inc. | | Oil & Gas Operator | Dec 2024 |
| 271 | Southwest Rig Service | | Oil & Gas Operator | Nov 1998 |
| 272 | Southwestern Electric Power Co | Dallas, TX 75266 | Oil & Gas Operator | Dec 1989 |
| 273 | Southwestern Energy Prod Co | Houston, TX 77032 | Oil & Gas Operator | Jun 2015 |
| 274 | Southwind Oil & Gas LLC | | Oil & Gas Operator | Dec 2023 |
| 275 | Sovereign Energy Corp. | | Oil Operator | Dec 2001 |
| 276 | Spartan Operating Company, Inc. | Tyler, TX 75702 | Oil & Gas Operator | Feb 2013 |
| 277 | Spartan Petroleum Corporation | Houston, TX 77079 | Oil & Gas Operator | Oct 1987 |
| 278 | Spartan Royalties, LLC | | Oil Operator | Dec 2024 |
| 279 | Special Energy Corp. | Stillwater, OK 74076 | Oil & Gas Operator | Feb 2026 |
| 280 | Speco Oil Company | | Oil & Gas Operator | Feb 1980 |
| 281 | Spectrum Opco LLC | | Oil & Gas Operator | Nov 2024 |
| 282 | Spicy Daugx Operators Louisiana LLC | | Oil & Gas Operator | Nov 2024 |
| 283 | Spillers Petroleum, Inc. | | Gas Operator | Mar 2010 |
| 284 | Spindletop Drilling Co. | Dallas, TX 75230 | Oil & Gas Operator | Feb 2026 |
| 285 | Spingas Energy, Inc. | | Oil & Gas Operator | Jun 2010 |
| 286 | Spirit Petroleum Company | | Oil & Gas Operator | Apr 1999 |
| 287 | Spokane Operating, LLC | | Oil & Gas Operator | Dec 2024 |
| 288 | Spooner & Marlin Expl., Inc. | | Oil & Gas Operator | Mar 1990 |
| 289 | Spooner Petroleum Company | | Oil & Gas Operator | Dec 2025 |
| 290 | Spyglass Oil & Gas LLC | | Oil & Gas Operator | Dec 2024 |
| 291 | Square Mile Energy, L.L.C. | Houston, TX 77057 | Oil & Gas Operator | Feb 2026 |
| 292 | Square One Corporation | Giddings, TX 78942 | Oil & Gas Operator | Dec 2012 |
| 293 | SRP Production Corp. | | Oil & Gas Operator | Nov 1997 |
| 294 | Ssi Energy LLC | | Oil & Gas Operator | Jul 2021 |
| 295 | SSM Partnership-PV79 | | Oil Operator | Jun 1989 |
| 296 | St Johns Operating #1 LP | Houston, TX 77060 | Oil & Gas Operator | Aug 2023 |
| 297 | St. Croix Corporation | | Oil & Gas Operator | Apr 1990 |
| 298 | St. Mary Energy Company | Houston, TX 77079 | Oil & Gas Operator | Aug 2008 |
| 299 | St. Mary Land & Exploration Co | Denver, CO 80201 | Oil & Gas Operator | Jun 2010 |
| 300 | St. Mary Operating Company | Denver, CO 80203 | Oil & Gas Operator | Mar 2019 |