| 301 | Hanson Corporation | New Braunfels, TX 78132 | Oil & Gas Operator | Mar 2008 |
| 302 | Harding Well Service Co. | Coahoma, TX 79511 | Oil & Gas Operator | Aug 2003 |
| 303 | Harmonia Petroleum Corporation | Missouri City, TX 77459 | Oil & Gas Operator | May 2017 |
| 304 | Harmony Drilling Company, Inc. | Denver, CO 80222 | Oil & Gas Operator | Nov 2016 |
| 305 | Hartoil Corporation | Post, TX 79356 | Oil & Gas Operator | May 2025 |
| 306 | Harvard Petroleum Corporation | Roswell, NM 88201 | Oil & Gas Operator | Dec 2004 |
| 307 | Hat Oil & Gas, Inc. | Slaton, TX 79364 | Oil & Gas Operator | Feb 2002 |
| 308 | Hawkeye Transmission Company | Dallas, TX 75244 | Oil & Gas Operator | Jun 2000 |
| 309 | Hayabusa Energy USA, LLC | Pampa, TX 79065 | Oil & Gas Operator | May 2025 |
| 310 | Hec Petroleum, Inc | Midland, TX 79705 | Oil & Gas Operator | Mar 2006 |
| 311 | Helmerich & Payne, Inc. | Tulsa, OK 74114 | Oil & Gas Operator | Feb 2025 |
| 312 | Helms Oil & Gas, LLC | Midland, TX 79710 | Oil & Gas Operator | May 2025 |
| 313 | Henderson & Erickson, Inc. | Midland, TX 79701 | Oil & Gas Operator | May 2025 |
| 314 | Hendrix, John H. Corporation | Midland, TX 79705 | Oil & Gas Operator | Sep 2018 |
| 315 | Henry Petroleum Corp. | Midland, TX 79703 | Oil & Gas Operator | Mar 2001 |
| 316 | Henry Petroleum LP | Midland, TX 79701 | Oil & Gas Operator | Dec 2008 |
| 317 | Henry Resources LLC | Midland, TX 79703 | Oil & Gas Operator | May 2025 |
| 318 | Herv Oil, LLC | Oklahoma City, OK 73116 | Oil Operator | Mar 2025 |
| 319 | Hexagon Oil And Gas Inc. | Fort Worth, TX 76132 | Oil & Gas Operator | May 2025 |
| 320 | Hexp Operating, LLC | Midland, TX 79705 | Oil & Gas Operator | May 2025 |
| 321 | Hibernia Resources IV, LLC | Houston, TX 77056 | Oil & Gas Operator | May 2025 |
| 322 | High Desert Resources, L.L.C. | Midland, TX 79704 | Oil Operator | May 2025 |
| 323 | Highmount Expl & Prod Texas LLC | Houston, TX 77002 | Oil & Gas Operator | Sep 2014 |
| 324 | Highpeak Energy Holdings, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | May 2025 |
| 325 | Hillin Simon/Prime Expl., L.C. | Midland, TX 79702 | Oil & Gas Operator | Jun 2000 |
| 326 | Hillin-Simon Oil Company | Houston, TX 77079 | Oil & Gas Operator | Mar 2013 |
| 327 | Hillside Oil & Gas, LLC | Midland, TX 79708 | Oil & Gas Operator | Apr 2016 |
| 328 | Hog Operating LLC | Dallas, TX 75201 | Oil & Gas Operator | May 2025 |
| 329 | Holly Petroleum, Inc. | Midland, TX 79702 | Oil & Gas Operator | Nov 2008 |
| 330 | Hopkins, T. M. Operating Co. | Kilgore, TX 75663 | Oil & Gas Operator | May 2025 |
| 331 | Houston Oil & Minerals Corp. | Houston, TX 77002 | Oil & Gas Operator | Aug 1996 |
| 332 | Hrubetz Operating Company | Dallas, TX 75225 | Oil & Gas Operator | Feb 1999 |
| 333 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | May 2025 |
| 334 | Ica Energy Operating, L.L.C. | Odessa, TX 79760 | Oil & Gas Operator | May 2025 |
| 335 | Ice Brothers, Inc. | Monahans, TX 79756 | Oil & Gas Operator | Jul 2024 |
| 336 | Ikard, Alan | Electra, TX 76360 | Oil & Gas Operator | May 2025 |
| 337 | Inexco Oil Company | Houston, TX 77210 | Oil & Gas Operator | Mar 2013 |
| 338 | Integras Operating, LLC | Irving, TX 75062 | Oil & Gas Operator | May 2025 |
| 339 | International Ventures, Inc. | Pogasa Springs, CO 81147 | Oil Operator | Jul 1996 |
| 340 | Ip Petroleum Company, Inc. | Houston, TX 77210 | Oil & Gas Operator | Mar 2008 |
| 341 | Ipact | Austin, TX 78734 | Oil & Gas Operator | May 2025 |
| 342 | Ipt Oil Company | Evansville, IN 47706 | Oil & Gas Operator | May 2025 |
| 343 | Ira Testers | Ira, TX 79527 | Oil & Gas Operator | Mar 2024 |
| 344 | J.H.R. Corporation | Bridgeville, PA 15017 | Oil & Gas Operator | Jul 2001 |
| 345 | Jagged Peak Energy LLC | Oklahoma City, OK 73126 | Oil & Gas Operator | May 2025 |
| 346 | Jamex, Inc. | Lewisville, TX 75067 | Oil & Gas Operator | May 2025 |
| 347 | Jay Management Company LLC | Houston, TX 77057 | Oil & Gas Operator | May 2025 |
| 348 | Jay Resources Corporation | Houston, TX 77010 | Oil & Gas Operator | Feb 1998 |
| 349 | Jetta Operating Company Inc | Fort Worth, TX 76102 | Oil & Gas Operator | May 2025 |
| 350 | Jin Petroleum LLC | New Braunfels, TX 78130 | Oil Operator | May 2025 |
| 351 | JM Cox Resources LP | Midland, TX 79702 | Oil & Gas Operator | Apr 2019 |
| 352 | JMW Resources, Inc. | Midland, TX 79701 | Oil & Gas Operator | May 2025 |
| 353 | JPM Eoc Operating, Inc. | Houston, TX 77010 | Oil & Gas Operator | Sep 2016 |
| 354 | Jtex Oil Company, LLC | Colorado City, TX 79512 | Oil & Gas Operator | Jan 2025 |
| 355 | Just Oil & Gas, Inc. | Graham, TX 76450 | Oil & Gas Operator | May 2025 |
| 356 | Jva Operating Company | Midland, TX 79710 | Oil & Gas Operator | Oct 2021 |
| 357 | K And R Oil Company | Stanton, TX 79782 | Oil & Gas Operator | Aug 2003 |
| 358 | K.M.A. Operating, Inc. | Graham, TX 76450 | Oil & Gas Operator | Aug 2003 |
| 359 | K.W.A., Inc. | Midland, TX 79702 | Oil & Gas Operator | May 2025 |
| 360 | Kaiser-Francis Oil Company | Tulsa, OK 74121 | Oil & Gas Operator | May 2025 |
| 361 | Kana Resources, Inc. | Dallas, TX 75243 | Oil & Gas Operator | Aug 2003 |
| 362 | Karico GP, LLC | Midland, TX 79705 | Oil & Gas Operator | May 2025 |
| 363 | KC Resources Inc | Snowmass VLG., CO 81615 | Oil & Gas Operator | Feb 2025 |
| 364 | KCS Resources, Inc. | Houston, TX 77002 | Oil & Gas Operator | Feb 2009 |
| 365 | Kebo Oil & Gas, Inc. | Portland, TX 78374 | Oil & Gas Operator | May 2025 |
| 366 | Keeley Oil, L.L.C. | Dallas, TX 75225 | Oil Operator | May 2025 |
| 367 | Kelsey Operating, Inc. | Houston, TX 77077 | Oil Operator | Feb 2022 |
| 368 | Kem Energy, Inc. | Katy, TX 77450 | Oil & Gas Operator | May 2025 |
| 369 | Kerr-McGee Corporation | Dallas, TX 75380 | Oil & Gas Operator | Mar 2025 |
| 370 | Kerr-McGee Oil & Gas Onshore LLC | The Woodlands, TX 77380 | Oil & Gas Operator | Feb 2017 |
| 371 | Kerr-McGee Oil & Gas Onshore LP | Houston, TX 77046 | Oil & Gas Operator | May 2025 |
| 372 | Kidd Oil & Gas, LC | Dallas, TX 75219 | Oil & Gas Operator | Apr 1999 |
| 373 | Kimbrough Engineering Co, LLC | New Braunfels, TX 78132 | Oil & Gas Operator | Dec 2014 |
| 374 | King Energy Resources | Kerrville, TX 78029 | Oil & Gas Operator | May 2025 |
| 375 | Klabzuba Operating Company | Fort Worth, TX 76102 | Oil & Gas Operator | Aug 2013 |
| 376 | Klabzuba Royalty Company | Prague, OK 74864-0567 | Oil & Gas Operator | Dec 2019 |
| 377 | L & D, Inc. | San Angelo, TX 76906 | Oil & Gas Operator | May 2019 |
| 378 | L.C.S. Production Company | Abilene, TX 79608 | Oil & Gas Operator | May 2025 |
| 379 | Lackey, William H. Oil And Gas | Shawnee, OK 74804 | Oil & Gas Operator | Feb 2024 |
| 380 | Ladd Operating Company | Midland, TX 79711 | Oil & Gas Operator | Mar 2008 |
| 381 | Lake Crystal Operating LLC | Sugar Land, TX 77496 | Oil & Gas Operator | May 2025 |
| 382 | Lakewood Operating, LTD. | Midland, TX 79702 | Oil & Gas Operator | May 2025 |
| 383 | Landmark Ip, LLC | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 384 | Landrick O & G Operating, LLC | Midland, TX 79705 | Oil & Gas Operator | May 2025 |
| 385 | Langford & Brigham Operating LLC | Austin, TX 78730 | Oil & Gas Operator | May 2025 |
| 386 | Langham Petroleum Expl. Corp. | Houston, TX 77056 | Oil & Gas Operator | Dec 2009 |
| 387 | Laredo Petroleum Inc | Tulsa, OK 74120 | Oil & Gas Operator | Mar 2023 |
| 388 | Lario Oil & Gas Company | Odessa, TX 79762 | Oil & Gas Operator | May 2025 |
| 389 | Latigo Petroleum Texas, LP | Houston, TX 77002 | Oil & Gas Operator | Feb 2009 |
| 390 | Leeper Oil Exp. & Prod. Inc. | Midland, TX 79701 | Oil & Gas Operator | Sep 2005 |
| 391 | Legacy Reserves Operating LP | Denver, CO 80201 | Oil & Gas Operator | May 2025 |
| 392 | Lemon, Richard F. Jr. | Carrollton, TX 75006 | Oil & Gas Operator | May 2025 |
| 393 | Liberty Resources Co. | Big Lake, TX 76932 | Oil & Gas Operator | Mar 1994 |
| 394 | Limark Corporation | Midland, TX 79702 | Oil & Gas Operator | Dec 2003 |
| 395 | Linn Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Jan 2019 |
| 396 | Linn Operating, Inc. | Houston, TX 77002 | Oil & Gas Operator | May 2017 |
| 397 | Lovelady, I. W. | Albuquerque, NM 87111 | Oil & Gas Operator | Jan 1996 |
| 398 | Lyco Energy Corporation | Dallas, TX 75206 | Oil & Gas Operator | Jun 2015 |
| 399 | Lynx Energy Company, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Mar 2008 |
| 400 | Lynx Operating Co., Inc. | Dallas, TX 75206 | Oil & Gas Operator | May 2025 |