| 1 | Ladd Petroleum Corp. | Denver, CO 80202 | Oil & Gas Operator | Oct 2004 |
| 2 | Lamar Hunt | | Oil & Gas Operator | Oct 2003 |
| 3 | Layline Petroleum I, LLC | Houston, TX 77024 | Oil & Gas Operator | May 2013 |
| 4 | Lear Petroleum Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | Aug 1999 |
| 5 | Leede Oil & Gas Inc. | Greenwood VLG, CO 80111 | Oil & Gas Operator | Aug 2003 |
| 6 | Legacy Oil & Gas ND, Inc. | | Oil & Gas Operator | Feb 2016 |
| 7 | Legacy Reserves Operating LP | Denver, CO 80201 | Oil & Gas Operator | Oct 2025 |
| 8 | Leland Oil & Gas, LLC | | Oil & Gas Operator | Aug 2025 |
| 9 | Liberty Resources LLC | | Oil & Gas Operator | May 2014 |
| 10 | Liberty Resources Management Co LLC | Denver, CO 80202 | Oil & Gas Operator | Aug 2025 |
| 11 | Lime Rock Resources III-A, L.P. | Houston, TX 77002 | Oil & Gas Operator | Aug 2025 |
| 12 | Lime Rock Resources V-A, LP | | Oil & Gas Operator | Aug 2025 |
| 13 | Lloyd H. Smith | | Oil & Gas Operator | Mar 1972 |
| 14 | Long Petroleum, Inc. | Shreveport, LA 71166 | Oil & Gas Operator | Jun 2020 |
| 15 | Louisiana Land & Exploration Co. | Houston, TX 77210 | Oil & Gas Operator | Sep 2013 |
| 16 | Lubar Oil Co. | | Oil Operator | Nov 1983 |
| 17 | Luff Exploration Company | Denver, CO 80203 | Oil & Gas Operator | Aug 2025 |
| 18 | Lyco Energy Corporation | Dallas, TX 75206 | Oil & Gas Operator | Jun 2015 |