| 1 | O & O Operators, LLC. | Fate, TX 75132 | Oil & Gas Operator | Jun 2025 |
| 2 | O.G.P. Operating, Inc. | Dallas, TX 75231 | Oil & Gas Operator | Jun 2025 |
| 3 | Oasis Petroleum Permian LLC | Houston, TX 77002 | Oil & Gas Operator | Jun 2025 |
| 4 | Occidental Energy Marketing, Inc. | Houston, TX 77227 | Gas Operator | Sep 2015 |
| 5 | Occidental Permian LTD. | Houston, TX 77046 | Oil & Gas Operator | Jun 2025 |
| 6 | Ocean Energy, Inc. | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 7 | Octane Energy Operating, LLC | Midland, TX 79701 | Oil & Gas Operator | Jun 2025 |
| 8 | Odessa Exploration, Inc. | Midland, TX 79702 | Oil & Gas Operator | Jun 2025 |
| 9 | Oga Operating L.L.C. | Midland, TX 79702 | Oil & Gas Operator | Jan 2000 |
| 10 | Ogx Operating, LLC | Midland, TX 79702 | Oil & Gas Operator | Jun 2025 |
| 11 | Oil & Gas Property MGMT., Inc. | Dallas, TX 75201 | Oil & Gas Operator | Jul 1996 |
| 12 | Oil Management Corporation | Dallas, TX 75206 | Oil & Gas Operator | Apr 2022 |
| 13 | Oilfield Management, Inc. (A) | Midland, TX 79702 | Oil & Gas Operator | Jun 2025 |
| 14 | Ojai Oil Company | Camarillo, CA 93012 | Oil & Gas Operator | Mar 2025 |
| 15 | Okla. Magic Circle Energy Corp. | Shawnee, OK 74801 | Oil & Gas Operator | Jul 2004 |
| 16 | Oklahoma RB Operating Company | Midland, TX 79701 | Oil & Gas Operator | Jan 1998 |
| 17 | Olsen Energy Inc. | Boerne, TX 78006 | Oil & Gas Operator | Jun 2025 |
| 18 | Omimex Petroleum Inc | Fort Worth, TX 76120 | Oil & Gas Operator | Aug 2022 |
| 19 | On Pointe Operating LLC | Jones, OK 73049 | Oil & Gas Operator | Jun 2025 |
| 20 | Opal Resources Operating Co.,LLC | Cypress, TX 77429 | Oil & Gas Operator | Jan 2019 |
| 21 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 22 | Osborn Heirs Co | San Antonio, TX 78217 | Oil & Gas Operator | Apr 2025 |
| 23 | Ovintiv USA Inc. | Denver, CO 80202 | Oil & Gas Operator | Jun 2025 |
| 24 | Owens Petroleum, Inc. | Midland, TX 79702 | Oil & Gas Operator | Aug 1995 |
| 25 | Oxbow Petroleum, LLC | Midland, TX 79703 | Oil & Gas Operator | Jun 2025 |
| 26 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Jun 2025 |
| 27 | Oxy USA WTP LP | Houston, TX 77046 | Oil & Gas Operator | Jun 2025 |
| 28 | Oxyrock Operating, LLC | Houston, TX 77046 | Oil & Gas Operator | Jun 2025 |