| 301 | HPC Incorporated | Denver, CO 80202 | Oil & Gas Operator | Nov 1998 |
| 302 | HRB Operating Company, Inc. | Bridgeport, TX 76426 | Oil & Gas Operator | Mar 2026 |
| 303 | HRC Production Co | Houston, TX 77024 | Oil & Gas Operator | Dec 2025 |
| 304 | HRF Exploration & Production LLC | Gaylord, MI 49734-0160 | Gas Operator | Mar 2026 |
| 305 | Hsumy Oil & Gas, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2007 |
| 306 | HT2 Exploration LLC | The Woodlands, TX 77381-4198 | Oil Operator | Dec 2025 |
| 307 | Hub-Hill Inc | San Antonio, TX 78230 | Oil Operator | Nov 1998 |
| 308 | Huber Energy Panhandle LP | Houston, TX 77079 | Oil & Gas Operator | Oct 2005 |
| 309 | Huber J M Corp | Edison, NJ 08837 | Oil & Gas Operator | Mar 2026 |
| 310 | Hubler John | Tulsa, OK 74133-2716 | Oil & Gas Operator | Mar 2015 |
| 311 | Huck Farms LLC | Stratford, OK 74872 | Oil & Gas Operator | Dec 2025 |
| 312 | Hudgens Lester E | Bartlesville, OK 74006-0215 | Oil Operator | Mar 2015 |
| 313 | Hudson Energy LLC | | Oil Operator | Dec 2025 |
| 314 | Hughes Drilling Co Inc | Enid, OK 73702 | Oil & Gas Operator | Apr 1998 |
| 315 | Hughes Gas Systems LLC | Oklahoma City, OK 73118-4821 | Oil & Gas Operator | Dec 2025 |
| 316 | Hughes George B | Asher, OK 74826-0165 | Oil & Gas Operator | Mar 2011 |
| 317 | Hugoton Energy Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Dec 2019 |
| 318 | Huitt Joe A | Tulsa, OK 74103 | Oil & Gas Operator | May 2001 |
| 319 | Huitt Joe A Rev Trust | Tulsa, OK 74103 | Oil & Gas Operator | Oct 2009 |
| 320 | Hulen Operating Company | Nichols Hill, OK 73116 | Oil & Gas Operator | Mar 2026 |
| 321 | Hull Enterprises Inc | Broken Arrow, OK 74012 | Oil & Gas Operator | Sep 2023 |
| 322 | Hull Oil Co. | Wichita Falls, TX 76308 | Oil & Gas Operator | Sep 2021 |
| 323 | Hulse Steve & Frank | Pawhuska, OK 74056 | Oil & Gas Operator | Aug 2000 |
| 324 | Hulsey Larry O & Co | Graham, TX 76046 | Oil & Gas Operator | Jun 2012 |
| 325 | Humphrey Mark | Morris, OK 74445-2816 | Oil & Gas Operator | Sep 2021 |
| 326 | Hungerford Oil & Gas Inc | Helena, OK 73741 | Oil & Gas Operator | Nov 2000 |
| 327 | Hunt Brothers Producing Co Inc | Redding, CA 96049-2516 | Oil & Gas Operator | Sep 2012 |
| 328 | Hunt Chris Water Hauling Contractor Inc | Keyes, OK 73947-0004 | Oil Operator | Jun 2008 |
| 329 | Hunt Energy Corporation | | Oil & Gas Operator | Feb 2002 |
| 330 | Hunt Engineering Inc | Norman, OK 73069-4093 | Oil & Gas Operator | Feb 2019 |
| 331 | Hunt H L | Dallas, TX 75202-2785 | Oil & Gas Operator | Jan 2025 |
| 332 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Mar 2026 |
| 333 | Hunt Petroleum Corp. | Dallas, TX 75201 | Oil & Gas Operator | Nov 2008 |
| 334 | Huntington Energy LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | Mar 2026 |
| 335 | Huntington Resources Inc | Tulsa, OK 74103 | Oil & Gas Operator | Oct 2006 |
| 336 | Hunton Oil & Gas Corporation | Oklahoma City, OK 73154-0191 | Oil & Gas Operator | May 2019 |
| 337 | Hunton Operating LLC | Oklahoma City, OK 73154 | Oil & Gas Operator | Jan 2026 |
| 338 | Hurd Oil Company | | Oil & Gas Operator | Jun 2015 |
| 339 | Hurley Charles B | Santa Ana, CA 92706 | Oil & Gas Operator | Apr 2015 |
| 340 | Hurricane Energy Corporation | | Oil & Gas Operator | Dec 2000 |
| 341 | Hurst Oil Investments Inc | Oklahoma City, OK 73172 | Oil & Gas Operator | Feb 2015 |
| 342 | Husky Petroleum | Seminole, OK 74818-1181 | Oil Operator | Feb 2012 |
| 343 | Husky Ventures Inc | Oklahoma City, OK 73134 | Oil & Gas Operator | Dec 2025 |
| 344 | Hutton Gas Operating Company | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2015 |
| 345 | Hux Oil Company LLC | Kingfisher, OK 73750 | Oil & Gas Operator | Dec 2025 |
| 346 | Hyalite Energy Corporation | Pampa, TX 79066 | Oil & Gas Operator | Dec 2025 |
| 347 | Hydrocarbon Management, Inc. | San Antonio, TX 78216 | Oil & Gas Operator | Dec 1996 |
| 348 | Hydrocarbon Technology Services | | Oil & Gas Operator | Dec 2000 |
| 349 | Hyperion Energy LP | Dallas, TX 75206 | Oil & Gas Operator | May 2014 |
| 350 | Hyperion Oil & Gas LLC | Dallas, TX 75251 | Oil & Gas Operator | Mar 2026 |