| 301 | Guinn Operating Company | Spring Branch, TX 78070 | Oil & Gas Operator | Feb 2014 |
| 302 | Gulfstar Properties, Inc. | San Antonio, TX 78229 | Oil & Gas Operator | May 2025 |
| 303 | Gulftex Energy II, LP | San Antonio, TX 78258 | Oil & Gas Operator | Jan 2013 |
| 304 | Gulftex Energy III, LP | San Antonio, TX 78257 | Oil & Gas Operator | Jul 2018 |
| 305 | Gulftex Energy IV, LP | San Antonio, TX 78257 | Oil & Gas Operator | Jul 2019 |
| 306 | Gulftex Energy, LLC | San Antonio, TX 78257 | Oil & Gas Operator | May 2025 |
| 307 | H & P Exploration Co. | Alice, TX 78333 | Oil & Gas Operator | May 2019 |
| 308 | H R E Rental Company | Premont, TX 78375 | Oil & Gas Operator | Sep 2015 |
| 309 | H-M Resource Management, Inc. | Houston, TX 77055 | Oil & Gas Operator | Feb 2023 |
| 310 | Haigood, Danny | Portland, TX 78374 | Oil & Gas Operator | Mar 2008 |
| 311 | Halcon Resources Operating, Inc. | Tulsa, OK 74135 | Oil & Gas Operator | Dec 2013 |
| 312 | Hamilton Brothers Oil Co. | Houston, TX 77057 | Oil & Gas Operator | Mar 2015 |
| 313 | Hamilton, J. R. | Carrizo SPGS, TX 78834 | Oil & Gas Operator | May 2025 |
| 314 | Hamon Operating Company | Dallas, TX 75201 | Oil & Gas Operator | Dec 2011 |
| 315 | Hanson Minerals Co. | Houston, TX 77042 | Oil & Gas Operator | Oct 1993 |
| 316 | Hanson Production Company | Cuero, TX 77954 | Oil & Gas Operator | Jul 2009 |
| 317 | Hardwick, Mark P. Inc. | Midland, TX 79702 | Oil & Gas Operator | Nov 1994 |
| 318 | Harper Hefte, Inc. | Corpus Chrsti, TX 78410 | Oil & Gas Operator | May 2025 |
| 319 | Harrison Interests, LTD. | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 320 | Harvey Brothers Oil & Gas | Corpus Chrsti, TX 78408 | Oil & Gas Operator | Jul 2004 |
| 321 | Harwood Exploration, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Aug 1995 |
| 322 | Hawk Exploration And Production | Corpus Chrsti, TX 78412 | Oil & Gas Operator | Oct 1995 |
| 323 | Hawk Petroleum, L L C | San Diego, TX 78384 | Oil & Gas Operator | May 2025 |
| 324 | Hawn Brothers | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2003 |
| 325 | Hawn Brothers Company | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Jan 2003 |
| 326 | Hawthorn Energy Partners, LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | May 2025 |
| 327 | HBC Oil Company, LLC | San Antonio, TX 78266 | Oil Operator | May 2025 |
| 328 | Headington Oil Company | Dallas, TX 75231 | Oil & Gas Operator | Dec 2016 |
| 329 | Hep Oil Company LTD | Gainesville, TX 76240 | Oil & Gas Operator | Mar 2012 |
| 330 | Hep Oil GP, LLC | Gainesville, TX 76241 | Oil & Gas Operator | Mar 2015 |
| 331 | Hermat Salt Water Disposal, Inc. | Corpus Chrsti, TX 78426 | Oil Operator | Aug 2012 |
| 332 | Herschap Bros. | Bruni, TX 78344 | Oil & Gas Operator | May 2025 |
| 333 | High Sierra Operating, LTD. | Canyon Lake, TX 78133 | Oil & Gas Operator | Mar 2008 |
| 334 | Hilcorp Energy Company | Houston, TX 77208 | Oil & Gas Operator | May 2025 |
| 335 | Hinds Petroleum, LLC | Houston, TX 77263 | Oil Operator | May 2025 |
| 336 | Hinds Petroleum, LP | Houston, TX 77263 | Oil Operator | Feb 2017 |
| 337 | Holcomb Company, The | Freer, TX 78357 | Oil & Gas Operator | Aug 1996 |
| 338 | Hollimon Oil Corporation | Castroville, TX 78009 | Oil & Gas Operator | Nov 2016 |
| 339 | Home Petroleum Corp | Victoria, TX 77902 | Oil & Gas Operator | May 2025 |
| 340 | Houston Oil & Minerals Corp. | Houston, TX 77002 | Oil & Gas Operator | Aug 1996 |
| 341 | Howard Exploration, Inc. | Houston, TX 77069 | Oil & Gas Operator | May 2025 |
| 342 | Howard, Douglas J. | Houston, TX 77070 | Oil & Gas Operator | Mar 2008 |
| 343 | Howitzer Operating, LLC | Dallas, TX 75380 | Oil Operator | May 2025 |
| 344 | HRH Energy Group Incorporated | Carrollton, TX 75006 | Oil & Gas Operator | Nov 2009 |
| 345 | Huber Energy L.P. | Houston, TX 77079 | Oil & Gas Operator | Feb 2007 |
| 346 | Huber Energy Panhandle LP | Houston, TX 77079 | Oil & Gas Operator | Oct 2005 |
| 347 | Huber J M Corp | Edison, NJ 08837 | Oil & Gas Operator | May 2025 |
| 348 | Hughes, Dan A. Company | Beeville, TX 78104 | Oil & Gas Operator | May 2006 |
| 349 | Hughes, Dan A. Company, L.P. | Beeville, TX 78104 | Oil & Gas Operator | May 2025 |
| 350 | Hugoton Operating Company, Inc. | Dallas, TX 75240 | Oil & Gas Operator | May 2025 |
| 351 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | May 2025 |
| 352 | Hunter Petroleum Inc. | Alice, TX 78333 | Oil & Gas Operator | May 2014 |
| 353 | Hurd Enterprises, LTD. | San Antonio, TX 78209 | Oil & Gas Operator | May 2025 |
| 354 | Hydrocarbon Operating, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | May 2025 |
| 355 | Imperial Oil Company | Houston, TX 77073 | Oil & Gas Operator | Oct 2004 |
| 356 | Inland Ocean, Inc. | San Antonio, TX 78205 | Oil & Gas Operator | May 2025 |
| 357 | Intercity Management Corp. | Corpus Chrsti, TX 78412 | Oil & Gas Operator | May 2025 |
| 358 | Ipact | Austin, TX 78734 | Oil & Gas Operator | May 2025 |
| 359 | Jalapeno Operating Company, LLC | Plntersville, TX 77363 | Oil Operator | May 2025 |
| 360 | Jay-Dee Operating Company | Corpus Chrsti, TX 78413 | Oil & Gas Operator | Aug 2000 |
| 361 | Jenco Petroleum Corporation | The Woodlands, TX 77380 | Oil Operator | May 2025 |
| 362 | Jenex Operating Company Of Texas | Denver, CO 80209 | Oil & Gas Operator | Aug 2003 |
| 363 | Jenex Petroleum Corporation | The Woodlands, TX 77380 | Oil & Gas Operator | May 2025 |
| 364 | Jetco Exploration | Victoria, TX 77903 | Oil & Gas Operator | May 2007 |
| 365 | JJ Production | Freer, TX 78357 | Oil & Gas Operator | May 2025 |
| 366 | JN Exploration & Production LP | Billings, MT 59103 | Oil & Gas Operator | Jan 2001 |
| 367 | Joe Kestner, L.L.C. | Corpus Chrsti, TX 78410 | Oil & Gas Operator | Feb 2016 |
| 368 | Johnson, William D. | Fort Worth, TX 76116 | Oil & Gas Operator | Mar 2008 |
| 369 | Jones, L. E. Operating, Inc. | Duncan, OK 73534 | Oil & Gas Operator | May 2025 |
| 370 | Jones, R. W. & Co., LTD. | Oklahoma City, OK 73132 | Oil & Gas Operator | Mar 1997 |
| 371 | Jones, R.W. & Co. II, LTD. | Edmond, OK 73034 | Oil & Gas Operator | Sep 2010 |
| 372 | Journey Operating, L.L.C. | Sugar Land, TX 77496 | Oil & Gas Operator | Aug 2006 |
| 373 | Joy Resources, Inc. | Houston, TX 77027 | Oil & Gas Operator | May 2025 |
| 374 | JPW Energy, L.L.C. | San Antonio, TX 78216 | Oil & Gas Operator | May 2025 |
| 375 | JTB Oil Company, Inc. | Refugio, TX 78377 | Oil & Gas Operator | May 2025 |
| 376 | Jura Energy Operating LLC | Houston, TX 77024 | Oil & Gas Operator | Jun 2023 |
| 377 | Kaiser-Francis Oil Company | Tulsa, OK 74121 | Oil & Gas Operator | May 2025 |
| 378 | Kaler Energy Corp. | Boerne, TX 78006 | Oil & Gas Operator | May 2025 |
| 379 | Karper Oil & Gas Corporation | Graham, TX 76450 | Oil & Gas Operator | May 2025 |
| 380 | Kaye Poth Oil Corp. | Seguin, TX 78155 | Oil & Gas Operator | May 1998 |
| 381 | KD Energy, LLC | Houston, TX 77056 | Oil & Gas Operator | May 2025 |
| 382 | Kebo Oil & Gas, Inc. | Portland, TX 78374 | Oil & Gas Operator | May 2025 |
| 383 | Keen Operating Company, Inc. | Austin, TX 78705 | Oil & Gas Operator | Aug 2001 |
| 384 | Keene, Roy J. Jr. | Sugar Land, TX 77498 | Oil & Gas Operator | Jun 2016 |
| 385 | Kemco Oil | Alice, TX 78332 | Oil & Gas Operator | Aug 2009 |
| 386 | Kestrel Resources, Inc. | Dallas, TX 75204 | Oil & Gas Operator | Jan 2017 |
| 387 | Key Production Company, Inc. | Longview, TX 75606 | Oil & Gas Operator | Mar 2025 |
| 388 | Keystone Operating Co. | Round Rock, TX 78681 | Oil & Gas Operator | May 2025 |
| 389 | Kibbe, Anna S. | Falfurrias, TX 78355 | Oil & Gas Operator | Sep 1998 |
| 390 | Killam Oil Co., LTD. | Laredo, TX 78042 | Oil & Gas Operator | May 2025 |
| 391 | Killam Oil Company | Laredo, TX 78042 | Oil & Gas Operator | Mar 1994 |
| 392 | Kinder Morgan Production Co LP | Midland, TX 79701 | Oil & Gas Operator | Jul 2007 |
| 393 | King Operating Corporation | Fort Worth, TX 76147 | Oil & Gas Operator | May 2025 |
| 394 | Kosarek, Charlie | San Antonio, TX 78213 | Oil & Gas Operator | Oct 2006 |
| 395 | KP Exploration, Inc. | Houston, TX 77002 | Oil & Gas Operator | Apr 1997 |
| 396 | Kriken Oil & Gas | Corpus Chrsti, TX 78426 | Oil & Gas Operator | Jul 2005 |
| 397 | L & F Drilling Co., Inc. (1) | Corpus Chrsti, TX 78479 | Oil & Gas Operator | May 2025 |
| 398 | L.L. Oil Company | Freer, TX 78357 | Oil & Gas Operator | May 2025 |
| 399 | L.T.D. Explorations Inc. | Alice, TX 78333 | Oil & Gas Operator | May 2025 |
| 400 | Lakeshore Operating, LLC | Wichita, KS 67203 | Oil & Gas Operator | May 2025 |