| 201 | Hallwood Petroleum, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jan 2025 |
| 202 | Hamman Oil & Refining Company | Houston, TX 77098 | Oil & Gas Operator | May 2025 |
| 203 | Hanson Minerals Co. | Houston, TX 77042 | Oil & Gas Operator | Oct 1993 |
| 204 | Hanson Production Company | Cuero, TX 77954 | Oil & Gas Operator | Jul 2009 |
| 205 | Harper Hefte, Inc. | Corpus Chrsti, TX 78410 | Oil & Gas Operator | May 2025 |
| 206 | Harvey Brothers Oil & Gas | Corpus Chrsti, TX 78408 | Oil & Gas Operator | Jul 2004 |
| 207 | Hawn Brothers | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2003 |
| 208 | Hayes Oil & Gas Co. | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2005 |
| 209 | Headington Oil Company | Dallas, TX 75231 | Oil & Gas Operator | Dec 2016 |
| 210 | Headington Oil Company LLC | Dallas, TX 75204 | Oil & Gas Operator | Apr 2016 |
| 211 | Headington Oil Company, L.P. | Dallas, TX 75231 | Oil & Gas Operator | Mar 2008 |
| 212 | Headline Resources, Inc. | Richardson, TX 75080 | Oil & Gas Operator | Aug 1997 |
| 213 | Henderson Petroleum Corp | San Angelo, TX 76906 | Oil & Gas Operator | Jul 2013 |
| 214 | Hilcorp Energy Company | Houston, TX 77208 | Oil & Gas Operator | May 2025 |
| 215 | Hill Operating LLC | Mineral Wells, TX 76068 | Oil & Gas Operator | Nov 2023 |
| 216 | Holden Energy Corporation | Ardmore, OK 73401 | Oil & Gas Operator | Mar 2015 |
| 217 | Hope Production, Inc. | Edinburg, TX 78540 | Oil & Gas Operator | Jan 2000 |
| 218 | Houston Exploration Co, The | Houston, TX 77002 | Oil & Gas Operator | Apr 2017 |
| 219 | Houston Petroleum Company | Houston, TX 77027 | Oil & Gas Operator | May 2025 |
| 220 | Howard Exploration, Inc. | Houston, TX 77069 | Oil & Gas Operator | May 2025 |
| 221 | Howitzer Operating, LLC | Dallas, TX 75380 | Oil Operator | May 2025 |
| 222 | Hughes, Dan A. Company | Beeville, TX 78104 | Oil & Gas Operator | May 2006 |
| 223 | Hughes, Dan A. Company, L.P. | Beeville, TX 78104 | Oil & Gas Operator | May 2025 |
| 224 | Hugoton Operating Company, Inc. | Dallas, TX 75240 | Oil & Gas Operator | May 2025 |
| 225 | Hunter Petroleum Inc. | Alice, TX 78333 | Oil & Gas Operator | May 2014 |
| 226 | Hurd Enterprises, LTD. | San Antonio, TX 78209 | Oil & Gas Operator | May 2025 |
| 227 | Hydrocarbon Operating, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | May 2025 |
| 228 | Ibc Petroleum, Inc. | San Antonio, TX 78258 | Oil & Gas Operator | May 2025 |
| 229 | Inland Ocean, Inc. | San Antonio, TX 78205 | Oil & Gas Operator | May 2025 |
| 230 | Integrated Operating Corporation | Dallas, TX 75243 | Oil & Gas Operator | May 2025 |
| 231 | Ipact | Austin, TX 78734 | Oil & Gas Operator | May 2025 |
| 232 | J-O'B Operating Company | Shreveport, LA 71135 | Oil & Gas Operator | May 2025 |
| 233 | J. & M. Well Service, Inc. | Electra, TX 76360 | Oil & Gas Operator | May 2025 |
| 234 | Jackson Energy Development, Inc. | Cedar Park, TX 78613 | Oil & Gas Operator | May 2025 |
| 235 | James Energy Corporation | Houston, TX 77227 | Oil & Gas Operator | Jan 1996 |
| 236 | Jetco Exploration | Victoria, TX 77903 | Oil & Gas Operator | May 2007 |
| 237 | Jilpetco, Inc. | Fort Worth, TX 76121 | Oil & Gas Operator | May 2025 |
| 238 | K-Bar Oil LLC | McPherson, KS 67460 | Oil Operator | Jan 2025 |
| 239 | K.M.A. Operating, Inc. | Graham, TX 76450 | Oil & Gas Operator | Aug 2003 |
| 240 | Ka Energy Op Co. LLC | Oakland, CA 94605 | Oil & Gas Operator | Oct 2021 |
| 241 | Kaiser-Francis Oil Company | Tulsa, OK 74121 | Oil & Gas Operator | May 2025 |
| 242 | Kaler Energy Corp. | Boerne, TX 78006 | Oil & Gas Operator | May 2025 |
| 243 | KCS Resources, Inc. | Houston, TX 77002 | Oil & Gas Operator | Feb 2009 |
| 244 | Kebo Oil & Gas, Inc. | Portland, TX 78374 | Oil & Gas Operator | May 2025 |
| 245 | Kelley Oil Corporation | Houston, TX 77002 | Oil & Gas Operator | Jan 2002 |
| 246 | Kerr-McGee Corporation | Dallas, TX 75380 | Oil & Gas Operator | Mar 2025 |
| 247 | Kerr-McGee Oil & Gas Onshore LLC | The Woodlands, TX 77380 | Oil & Gas Operator | Feb 2017 |
| 248 | Kerr-McGee Oil & Gas Onshore LP | Houston, TX 77046 | Oil & Gas Operator | May 2025 |
| 249 | Kestrel Resources, Inc. | Dallas, TX 75204 | Oil & Gas Operator | Jan 2017 |
| 250 | Killam Oil Co., LTD. | Laredo, TX 78042 | Oil & Gas Operator | May 2025 |
| 251 | Killam Oil Company | Laredo, TX 78042 | Oil & Gas Operator | Mar 1994 |
| 252 | Kinder Morgan Tejas Pipeline LLC | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 253 | Kovar Operating, LLC | Victoria, TX 77901 | Oil & Gas Operator | Sep 2021 |
| 254 | KP Exploration, Inc. | Houston, TX 77002 | Oil & Gas Operator | Apr 1997 |
| 255 | Kukui Operating Company | Ignacio, CO 81137 | Oil & Gas Operator | May 2013 |
| 256 | L & B Oil And Gas Equipment, LLC | Palmhurst, TX 78573 | Oil & Gas Operator | May 2025 |
| 257 | L & F Drilling Co., Inc. (1) | Corpus Chrsti, TX 78479 | Oil & Gas Operator | May 2025 |
| 258 | L & R Energy Corporation | Spearman, TX 79081 | Oil & Gas Operator | Nov 2014 |
| 259 | L-Texx Petroleum, LP | Arlington, TX 76013 | Oil & Gas Operator | May 2025 |
| 260 | L.T.D. Explorations Inc. | Alice, TX 78333 | Oil & Gas Operator | May 2025 |
| 261 | Lakeshore Operating, LLC | Wichita, KS 67203 | Oil & Gas Operator | May 2025 |
| 262 | Laredo Energy, LP | Houston, TX 77040 | Oil & Gas Operator | Oct 2003 |
| 263 | Latigo Petroleum Texas, LP | Houston, TX 77002 | Oil & Gas Operator | Feb 2009 |
| 264 | Latigo Petroleum, Inc. | Tulsa, OK 74119 | Oil & Gas Operator | Feb 2025 |
| 265 | Legacy Corporation, The | Cedar Park, TX 78613 | Oil & Gas Operator | Jun 2004 |
| 266 | Legend Natural Gas III, LP | Houston, TX 77094 | Oil & Gas Operator | Feb 2015 |
| 267 | Legend Natural Gas IV, LP | Houston, TX 77094 | Oil & Gas Operator | Feb 2015 |
| 268 | Lighthouse Exploration, Inc. | Corpus Chrsti, TX 78473 | Oil & Gas Operator | Jul 2007 |
| 269 | Limark Corporation | Midland, TX 79702 | Oil & Gas Operator | Dec 2003 |
| 270 | Lindenmuth & Associates Inc | Austin, TX 78703 | Oil & Gas Operator | Aug 2024 |
| 271 | Linder Oil Company,A Partnership | Shreveport, LA 71136 | Oil & Gas Operator | May 2025 |
| 272 | Little, Lou Operating Co., Inc. | Portland, TX 78374 | Oil & Gas Operator | Sep 2014 |
| 273 | Lpes, Inc. | Provo, UT 84604 | Oil & Gas Operator | Nov 2018 |
| 274 | Luca Resources Group, LLC | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 275 | Lynx Energy Company, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Mar 2008 |
| 276 | M. J. G., Inc. | Alice, TX 78333 | Oil & Gas Operator | Jul 2010 |
| 277 | Maddux, Elizabeth H. | San Antonio, TX 78217 | Oil & Gas Operator | Nov 1995 |
| 278 | Magnum Engineering Company | Corpus Chrsti, TX 78401 | Oil & Gas Operator | May 2025 |
| 279 | Magnum Producing & Operating Co. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jan 2004 |
| 280 | Magnum Producing, LP | Corpus Chrsti, TX 78401 | Oil & Gas Operator | May 2025 |
| 281 | Manley, John D. III, Oper., Inc | Corpus Chrsti, TX 78404 | Oil & Gas Operator | Feb 2016 |
| 282 | Manti Operating Company | Covington, LA 70435 | Oil & Gas Operator | May 2025 |
| 283 | Mark IV Energy | San Antonio, TX 78213 | Oil & Gas Operator | Apr 1993 |
| 284 | Marquee Corporation | Houston, TX 77024 | Oil & Gas Operator | May 2025 |
| 285 | Marwell Petroleum LTD Partnrship | Houston, TX 77027 | Oil & Gas Operator | May 2025 |
| 286 | Marwell Petroleum, Inc. | Houston, TX 77057 | Oil & Gas Operator | Apr 2006 |
| 287 | Mass Energy, Inc | Houston, TX 77056 | Oil & Gas Operator | Mar 2008 |
| 288 | Maverick Brothers Operating,Inc. | Enid, OK 73702 | Oil & Gas Operator | May 2025 |
| 289 | McDay Energy Corp. | Dallas, TX 75206 | Oil & Gas Operator | May 2025 |
| 290 | McDonald & Johnson Resources,LLC | Cypress, TX 77429 | Oil & Gas Operator | Dec 2010 |
| 291 | McEna Inc | Tulsa, OK 74135 | Oil & Gas Operator | Jul 2005 |
| 292 | McFarland Energy, Inc. | New Orleans, LA 70160 | Oil & Gas Operator | Dec 2009 |
| 293 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | May 2025 |
| 294 | Messy Oil And Gas, LLC | Garwood, TX 77442 | Oil & Gas Operator | May 2025 |
| 295 | Metano Energy III, LP | Tulsa, OK 74121 | Oil & Gas Operator | May 2025 |
| 296 | Metano Energy, LP | San Antonio, TX 78216 | Oil & Gas Operator | Aug 2008 |
| 297 | MGM Well Service, Inc. | Corpus Chrsti, TX 78427 | Oil & Gas Operator | Oct 2004 |
| 298 | Midpar L.P. | Midland, TX 79702 | Oil & Gas Operator | Feb 1995 |
| 299 | Milagro Exploration, LLC | Houston, TX 77010 | Oil & Gas Operator | Aug 2018 |
| 300 | Millennium Petro-Physics, Inc. | Corpus Chrsti, TX 78480 | Oil & Gas Operator | May 2025 |