| 1 | H & M Resources LLC | Dallas, TX 75225 | Oil & Gas Operator | Jun 2025 |
| 2 | H-M Resource Management, Inc. | Houston, TX 77055 | Oil & Gas Operator | Feb 2023 |
| 3 | H. & J. Drilling Company | Fort Worth, TX 76114 | Oil & Gas Operator | Aug 2003 |
| 4 | Hamilton, John M. | Wichita Falls, TX 76301 | Oil & Gas Operator | May 2001 |
| 5 | Hamilton-Tedford Oper. Co., LLC | Wichita Falls, TX 76301 | Oil Operator | May 2007 |
| 6 | Hamman Oil & Refining Company | Houston, TX 77098 | Oil & Gas Operator | Jun 2025 |
| 7 | Hanson Minerals Co. | Houston, TX 77042 | Oil & Gas Operator | Oct 1993 |
| 8 | Hanson Production Company | Cuero, TX 77954 | Oil & Gas Operator | Jul 2009 |
| 9 | Harmony Drilling Company, Inc. | Denver, CO 80222 | Oil & Gas Operator | Nov 2016 |
| 10 | Harper Hefte, Inc. | Corpus Chrsti, TX 78410 | Oil & Gas Operator | Jun 2025 |
| 11 | Harrison Interests, LTD. | Houston, TX 77002 | Oil & Gas Operator | Jun 2025 |
| 12 | Hawn Brothers | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2003 |
| 13 | Hawn Brothers Company | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Jan 2003 |
| 14 | Hawthorn Energy Partners, LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | Jun 2025 |
| 15 | Hedrick Production Inc. | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Jun 2025 |
| 16 | Heritage Operating Co., Inc. The | Stafford, TX 77497 | Oil & Gas Operator | May 1997 |
| 17 | Herv Oil, LLC | Oklahoma City, OK 73116 | Oil Operator | Apr 2025 |
| 18 | High Sierra Operating, LTD. | Canyon Lake, TX 78133 | Oil & Gas Operator | Mar 2008 |
| 19 | Hilcorp Energy Company | Houston, TX 77208 | Oil & Gas Operator | Jun 2025 |
| 20 | Hill Production Company No. 2 | Kilgore, TX 75663 | Oil & Gas Operator | Jun 2025 |
| 21 | Hollimon Oil Corporation | Castroville, TX 78009 | Oil & Gas Operator | Nov 2016 |
| 22 | Home Petroleum Corp | Victoria, TX 77902 | Oil & Gas Operator | Jun 2025 |
| 23 | Houston Gulf Energy Corporation | The Woodlands, TX 77380 | Oil & Gas Operator | Jun 2025 |
| 24 | Howard, Douglas J. | Houston, TX 77070 | Oil & Gas Operator | Mar 2008 |
| 25 | Hughes, Dan A. Company | Beeville, TX 78104 | Oil & Gas Operator | May 2006 |
| 26 | Hughes, Dan A. Company, L.P. | Beeville, TX 78104 | Oil & Gas Operator | Jun 2025 |
| 27 | Hugoton Operating Company, Inc. | Dallas, TX 75240 | Oil & Gas Operator | Jun 2025 |
| 28 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Jun 2025 |
| 29 | Hunter Petroleum Inc. | Alice, TX 78333 | Oil & Gas Operator | May 2014 |
| 30 | Hurd Enterprises, LTD. | San Antonio, TX 78209 | Oil & Gas Operator | Jun 2025 |
| 31 | Hydrocarbon Management, Inc. | San Antonio, TX 78216 | Oil & Gas Operator | Dec 1996 |
| 32 | Hyquest Energy, Inc. | Midland, TX 79710 | Oil & Gas Operator | Mar 2015 |