| 1 | H & L Operating Co., L.L.P. | Amarillo, TX 79114 | Oil & Gas Operator | Aug 2022 |
| 2 | H & L Operating Company | Amarillo, TX 79114 | Oil & Gas Operator | Feb 2020 |
| 3 | H G & G Inc | Edmond, OK 73034 | Oil & Gas Operator | Jan 2006 |
| 4 | H2ox Operating LLC | Tulsa, OK 74103 | Oil Operator | Jul 2025 |
| 5 | Hadaway Consulting And Engineering LLC | Canadian, TX 79014 | Oil & Gas Operator | Jul 2025 |
| 6 | Hadaway Engineering Inc | Canadian, TX 79014 | Oil & Gas Operator | Jul 2015 |
| 7 | Hadson Petro USA Inc | | Oil & Gas Operator | Nov 2016 |
| 8 | Halcon Holdings Inc | Ada, OK 74820 | Oil & Gas Operator | Jun 2025 |
| 9 | Hallwood Petroleum, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jun 2025 |
| 10 | Hamilton Brothers Oil Co. | Houston, TX 77057 | Oil & Gas Operator | Mar 2015 |
| 11 | Hamon Operating Company | Dallas, TX 75201 | Oil & Gas Operator | Dec 2011 |
| 12 | Hanover Operating Company | Tulsa, OK 74101 | Oil & Gas Operator | Dec 1998 |
| 13 | Harbor Resources LLC | Oklahoma City, OK 73120 | Oil & Gas Operator | Oct 2025 |
| 14 | Harding & Shelton Inc | Oklahoma City, OK 73104-2410 | Oil & Gas Operator | Jun 2025 |
| 15 | Harken Exploration Company | Houston, TX 77079 | Oil & Gas Operator | Mar 2008 |
| 16 | Harris Oil & Gas Company | Denver, CO 80202 | Oil & Gas Operator | Jun 2016 |
| 17 | Hawkins Oil & Gas Inc | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2016 |
| 18 | Hazlewood Oil & Gas Co Inc | Oklahoma City, OK 73139-9353 | Oil & Gas Operator | Apr 2022 |
| 19 | Headington Oil Company | Dallas, TX 75231 | Oil & Gas Operator | Dec 2016 |
| 20 | Headington Oil Company LLC | Dallas, TX 75204 | Oil & Gas Operator | Apr 2016 |
| 21 | Helmerich & Payne, Inc. | Tulsa, OK 74114 | Oil & Gas Operator | Jun 2025 |
| 22 | Hi-Kat Petroleum Company | Liberal, KS 67905-1261 | Oil & Gas Operator | May 2014 |
| 23 | Hill John H | Dallas, TX 75240-7077 | Oil & Gas Operator | Jul 2015 |
| 24 | Himco Oil & Gas, Inc. | Enid, OK 73702 | Oil & Gas Operator | Jun 2025 |
| 25 | His Energy Corporation Inc | Newcastle, OK 73065-1461 | Oil Operator | Feb 2018 |
| 26 | Holke Dave Consulting Inc | Meridian, ID 83646-4812 | Oil & Gas Operator | Jun 2025 |
| 27 | Holt Oil & Gas Corp | Dallas, TX 75231 | Oil & Gas Operator | Apr 1995 |
| 28 | Home Petroleum Corp | Victoria, TX 77902 | Oil & Gas Operator | Oct 2025 |
| 29 | Hondo Oil & Gas Company | Roswell, NM 88202 | Oil & Gas Operator | Aug 2006 |
| 30 | Horizon Natural Gas Company | Tulsa, OK 74170 | Oil & Gas Operator | Oct 2024 |
| 31 | Horizon Natural Resources, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Jan 2019 |
| 32 | Hosco Operating Inc | Seminole, OK 74868-2447 | Oil & Gas Operator | Aug 2017 |
| 33 | Huber J M Corp | Edison, NJ 08837 | Oil & Gas Operator | Oct 2025 |
| 34 | Hugoton Energy Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Dec 2019 |
| 35 | Hull Oil Co. | Wichita Falls, TX 76308 | Oil & Gas Operator | Sep 2021 |
| 36 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Oct 2025 |
| 37 | Hunt Petroleum Corporation | Dallas, TX 75201 | Oil & Gas Operator | Nov 2008 |
| 38 | Huntington Energy LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | Oct 2025 |