| 1 | T.O.I. | Midland, TX 79710 | Oil & Gas Operator | Mar 2001 |
| 2 | Tahoe Exploration Inc. | Abilene, TX 79608 | Oil & Gas Operator | Mar 2016 |
| 3 | Tamarack Petroleum Company, Inc. | Midland, TX 79701 | Oil & Gas Operator | Feb 2026 |
| 4 | Tanglewood Production | Breckenridge, TX 76424 | Oil & Gas Operator | May 2009 |
| 5 | Taurus Operating, Inc. | Midland, TX 79710 | Oil & Gas Operator | Feb 2026 |
| 6 | TC Energy LLC | Covington, OK 73730-2116 | Oil & Gas Operator | Sep 2014 |
| 7 | TCS Petroleum Co., LLC | Abilene, TX 79608 | Oil & Gas Operator | Feb 2026 |
| 8 | TDC Engineering, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Feb 2026 |
| 9 | Teague Operating Co. | Mabank, TX 75147 | Oil & Gas Operator | Jul 1995 |
| 10 | Terrace Petroleum Corporation | Midland, TX 79701 | Oil & Gas Operator | Jul 2013 |
| 11 | Terrell Oil & Gas Production Co. | Hamlin, TX 79520 | Oil & Gas Operator | Feb 2026 |
| 12 | Tex-Ann Oil & Gas Services, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Feb 2026 |
| 13 | Tex-Atic Resources, Inc. | S. Lake Tahoe, CA 96150 | Oil & Gas Operator | Feb 2026 |
| 14 | Texaco E & P Inc. | Houston, TX 77099 | Oil & Gas Operator | Feb 2026 |
| 15 | Texas Pharchem Inc. | Abilene, TX 79601 | Oil & Gas Operator | Apr 2019 |
| 16 | Texical, Inc. | Katy, TX 77491 | Oil & Gas Operator | Feb 2026 |
| 17 | Texoma Oil Tools, Inc. | Wichita Falls, TX 76308 | Oil & Gas Operator | Feb 2026 |
| 18 | Texstar North America, Inc. | Waynesboro, MS 39367 | Oil & Gas Operator | Aug 1994 |
| 19 | Texxol Operating Company, Inc. | Fort Worth, TX 76108 | Oil & Gas Operator | Feb 2026 |
| 20 | Texzona Oil & Gas, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Dec 1997 |
| 21 | Thompson, Richard W. Inc. | Plano, TX 75024 | Oil & Gas Operator | Feb 2026 |
| 22 | Threshold Development Company | Fort Worth, TX 76109 | Oil & Gas Operator | Aug 2016 |
| 23 | Tiburon Oil & Gas, Inc. | Midland, TX 79701 | Oil & Gas Operator | Aug 2000 |
| 24 | Titan Energy, Inc. | Austin, TX 78703 | Oil & Gas Operator | Feb 2026 |
| 25 | Townsend Company | Abilene, TX 79608 | Oil & Gas Operator | Dec 2021 |
| 26 | Tuthill & Barbee | Amarillo, TX 79101 | Oil & Gas Operator | Nov 1994 |
| 27 | Txu Lone Star Pipeline | Dallas, TX 75201 | Oil & Gas Operator | Oct 2003 |