| 601 | Legacy Energy Inc | Carpinteria, CA 93013 | Oil & Gas Operator | Jun 2012 |
| 602 | Legacy Reserves Operating LP | Denver, CO 80201 | Oil & Gas Operator | Jul 2026 |
| 603 | Levinson Partners Corporation | Denver, CO 80202 | Oil & Gas Operator | Jul 1995 |
| 604 | Lewis & Clark Exploration | | Oil Operator | Feb 1989 |
| 605 | Lewis Yale H | | Oil & Gas Operator | Aug 1986 |
| 606 | Lexicon Resources Corporation | | Oil & Gas Operator | Apr 1986 |
| 607 | Liberty Production Co | Houston, TX 77002 | Oil & Gas Operator | Nov 1994 |
| 608 | Liberty Resources Management Co LLC | Denver, CO 80202 | Oil & Gas Operator | May 2026 |
| 609 | Lilis Energy Inc | Denver, CO 80203 | Oil & Gas Operator | Aug 2017 |
| 610 | Lincero LLC | Sinclair, WY 82334 | Oil Operator | May 2026 |
| 611 | Linn Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | Jan 2019 |
| 612 | Lissolo J W | Yuma, AZ 85365 | Oil & Gas Operator | Feb 2017 |
| 613 | Lissolo Timothy C | Newcastle, WY 82701 | Oil Operator | May 2026 |
| 614 | Llosu Corporation | Rawlins, WY 82301 | Oil & Gas Operator | Mar 2002 |
| 615 | Loco | Casper, WY 82602 | Oil & Gas Operator | Jul 2022 |
| 616 | Lodestone Operating | Portland, TX 78374 | Oil & Gas Operator | Apr 2026 |
| 617 | Loil Oil LLC | Golden, CO 80402 | Oil & Gas Operator | Mar 2026 |
| 618 | Lone Star Land And Energy II LLC | Dallas, TX 75214 | Oil & Gas Operator | Jan 2020 |
| 619 | Long Beach Oil Development Co | Glendale, CA 91203 | Oil & Gas Operator | Jun 2004 |
| 620 | Long Trust The | Kilgore, TX 75663 | Oil & Gas Operator | Aug 2008 |
| 621 | Longs Peak Resources LLC | Houston, TX 77019 | Oil & Gas Operator | Jun 2026 |
| 622 | Loral Operating LLC | Sheridan, WY 82801 | Gas Operator | Apr 2011 |
| 623 | Louisiana Land & Exploration Co. | Houston, TX 77210 | Oil & Gas Operator | Sep 2013 |
| 624 | Loundagin N B | Casper, WY 82602 | Oil & Gas Operator | Sep 2015 |
| 625 | Low D J | Littleton, CO 80127 | Oil Operator | Dec 1999 |
| 626 | Lowry Exploration Inc | Tulsa, OK 74119 | Oil & Gas Operator | Apr 2026 |
| 627 | Luff Exploration | Denver, CO 80203 | Oil & Gas Operator | Dec 2006 |
| 628 | Lusk Operating LLC | Denver, CO 80202 | Oil Operator | Jun 2017 |
| 629 | Lyco Operating Company | Dallas, TX 75206 | Gas Operator | Dec 1997 |
| 630 | M & C Oil Inc | Indianola, NE 68034 | Oil & Gas Operator | Nov 2013 |
| 631 | M & G Oil And Gas Inc | Llabarge, WY 83123 | Oil & Gas Operator | Apr 2023 |
| 632 | M & K Oil Company LLC | Gillette, WY 82716 | Oil & Gas Operator | May 2026 |
| 633 | M & K Oil Operations | | Oil & Gas Operator | Sep 1994 |
| 634 | M G Production Co | Rock Springs, WY 82901 | Oil Operator | Dec 1999 |
| 635 | M K M Oil Company | Casper, WY 82602 | Oil & Gas Operator | Jun 1996 |
| 636 | M W Petroleum Company | Houston, TX 77056 | Oil & Gas Operator | Dec 1995 |
| 637 | M-3 Industries | Casper, WY 82602 | Oil & Gas Operator | Mar 2026 |
| 638 | M2S Oil LLC | | Oil Operator | Apr 2026 |
| 639 | Mack Energy Corporation | Artesia, NM 88211 | Oil & Gas Operator | May 2026 |
| 640 | Macum Energy Inc | Billings, MT 59104 | Oil & Gas Operator | Aug 2021 |
| 641 | Maguire Oil Company | Dallas, TX 75270 | Oil & Gas Operator | Mar 2015 |
| 642 | Maha Energy Us Inc | | Oil Operator | Nov 2023 |
| 643 | Main Energy, Inc. | Houston, TX 77079 | Oil & Gas Operator | May 2009 |
| 644 | Majestic Petroleum Operations Inc | Story, WY 82842 | Gas Operator | Mar 2007 |
| 645 | Mak-J Energy Wyoming LLC | Denver, CO 80620 | Oil & Gas Operator | Nov 2012 |
| 646 | Mallon Oil Company | Denver, CO 80202 | Oil & Gas Operator | Jun 2005 |
| 647 | Manewal Bradley Oil Company | Newcastle, WY 82701 | Oil & Gas Operator | Aug 2013 |
| 648 | Manx Oil Corporation | Casper, WY 82601 | Oil & Gas Operator | Jun 2010 |
| 649 | Mapco Oil Company | | Oil & Gas Operator | Jan 1985 |
| 650 | Mar/Reg Investments | Irving, TX 75016 | Oil & Gas Operator | Jul 1999 |
| 651 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | May 2026 |
| 652 | Markus Production | Littleton, CO 80123 | Oil & Gas Operator | May 2026 |
| 653 | Marlin Oil Company LLC | Gillette, WY 82718 | Oil & Gas Operator | Mar 2023 |
| 654 | Marmik Oil Company | El Dorado, AR 71730 | Oil & Gas Operator | Jan 2015 |
| 655 | Marquis-Allred Eng Inc | | Oil & Gas Operator | Apr 1992 |
| 656 | Marshall & Winston, Inc. | Midland, TX 79710 | Oil & Gas Operator | May 2026 |
| 657 | Martens & Peck Operating Co | | Gas Operator | Feb 1997 |
| 658 | Martens & Peck Production Co | Denver, CO 80222 | Oil & Gas Operator | Feb 1997 |
| 659 | Martin Exploration | Westminster, CO 80030 | Oil & Gas Operator | Dec 1993 |
| 660 | Materi Exploration Inc | Upton, WY 82730 | Oil Operator | Nov 2021 |
| 661 | Matrix Production Company | Sugar Land, TX 77478 | Oil & Gas Operator | May 2026 |
| 662 | Maxim Drilling & Expl Inc | Gillette, WY 82717 | Oil & Gas Operator | May 2026 |
| 663 | Maximus Operating, LTD. | Kilgore, TX 75663 | Oil & Gas Operator | Jul 2026 |
| 664 | Mbi Oil & Gas LLC | Dickinson, ND 58601 | Oil & Gas Operator | May 2026 |
| 665 | McAdams Roux & Associates | Denver, CO 80202 | Oil & Gas Operator | Dec 1999 |
| 666 | McCartney Engineering LLC | Wheat Ridge, CO 80033 | Oil & Gas Operator | May 2026 |
| 667 | McClure Enterprises | Recluse, WY 82725 | Oil & Gas Operator | Dec 2025 |
| 668 | McCulliss Resource Company Inc | Denver, CO 80202 | Oil & Gas Operator | Jun 1999 |
| 669 | McEna Inc | Tulsa, OK 74135 | Oil & Gas Operator | Jul 2005 |
| 670 | McGuire John C | Gillette, WY 82717 | Oil & Gas Operator | Oct 2005 |
| 671 | McKenzie Production Company | Houston, TX 77063 | Oil & Gas Operator | May 1995 |
| 672 | MCL 1 Oil & Gas Wyoming LLC | Minneapolis, MN 55402 | Oil & Gas Operator | Jul 2018 |
| 673 | MCM Operating LLC | Midland, TX 79702 | Oil & Gas Operator | Jul 2026 |
| 674 | McMahon-Bullington LP | Wichita Falls, TX 76307 | Oil & Gas Operator | Apr 2009 |
| 675 | McMurry Energy Company | | Oil & Gas Operator | Dec 2001 |
| 676 | McMurry Oil LLC | Denver, CO 80202 | Oil & Gas Operator | Dec 2004 |
| 677 | McO Resources Corporation | | Oil & Gas Operator | Feb 1986 |
| 678 | McQueen Ed & Company Inc | Lindsey, OK 73052 | Oil & Gas Operator | Apr 2014 |
| 679 | McRae & Henry LTD | Golden, CO 80401 | Oil & Gas Operator | May 2022 |
| 680 | MDS Energy Development LLC | | Oil & Gas Operator | May 2026 |
| 681 | Meadow Deep LLC | | Oil & Gas Operator | May 2026 |
| 682 | Medallion Exploration | Holladay, UT 84117 | Oil & Gas Operator | Dec 2015 |
| 683 | Medallion Petroleum, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2015 |
| 684 | Medallion Production Company | Tulsa, OK 74103 | Oil & Gas Operator | May 1997 |
| 685 | Medicine Bow Operating Company | Houston, TX 77002 | Oil & Gas Operator | Apr 2014 |
| 686 | Meerkat Logistics And Operations LLC | Tuscaloosa, AL 35401 | Oil Operator | May 2026 |
| 687 | Mega Energy LLC | Gillette, WY 82718 | Gas Operator | May 2026 |
| 688 | Mels Water Service Inc | Lysite, WY 82642 | Oil Operator | Mar 2013 |
| 689 | Memorial Exploration Company | Saint Louis, MO 63105 | Oil & Gas Operator | Aug 1996 |
| 690 | Memorial Production Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Jul 2026 |
| 691 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Jul 2026 |
| 692 | Merit Productions | | Oil Operator | Sep 1996 |
| 693 | Meritage Energy Company LLC | Denver, CO 80202 | Oil & Gas Operator | May 2013 |
| 694 | Meritage Energy Partners LLC | Denver, CO 80202 | Oil & Gas Operator | Dec 2005 |
| 695 | Merrico Resources | | Oil Operator | Mar 1992 |
| 696 | Merrion Oil & Gas Corp | Farmington, NM 87401 | Oil & Gas Operator | May 2026 |
| 697 | Methane Productions Inc | Recluse, WY 82725 | Oil & Gas Operator | Apr 2007 |
| 698 | Meyer Douglas P | Longmont, CO 80501 | Oil & Gas Operator | Aug 2006 |
| 699 | Mi3 Energy LLC | | Oil & Gas Operator | May 2026 |
| 700 | Michigan-Wisconsin Pipe Line Co | | Oil & Gas Operator | Dec 1983 |