| 401 | Keystone Energy Oil & Gas Inc | Pittsburgh, PA 15222 | Oil & Gas Operator | Dec 2016 |
| 402 | Kidder Exploration Inc | Jamestown, NY 14701-5613 | Gas Operator | Dec 1991 |
| 403 | Kimmel Glenn | Shelocta, PA 15774-2233 | Gas Operator | Dec 2024 |
| 404 | Kis Oil & Gas Inc | Brookville, PA 15825-4210 | Oil & Gas Operator | Dec 2014 |
| 405 | Koebley Timothy W | Warren, PA 16365-2102 | Oil & Gas Operator | Dec 2024 |
| 406 | Kriebel Acquisition Co LLC | Clarion, PA 16214-6161 | Oil & Gas Operator | Dec 2024 |
| 407 | Kriebel Gas Inc | Clarion, PA 16214-0765 | Oil & Gas Operator | Dec 1999 |
| 408 | Kriebel Minerals Inc | Clarion, PA 16214-6161 | Oil & Gas Operator | Dec 2020 |
| 409 | Kriebel Natural Gas Co LLC | Clarion, PA 16214-6161 | Oil & Gas Operator | Dec 2024 |
| 410 | KSM Energy Inc | Pittsburgh, PA 15238-3156 | Gas Operator | Dec 2024 |
| 411 | Kylander Oil Inc | Warren, PA 16365-4366 | Oil & Gas Operator | Dec 2024 |
| 412 | Kyle Energy Inc NV | Apollo, PA 15613-0249 | Gas Operator | Dec 1996 |
| 413 | L & B Energy LLP | Kingsville, OH 44048 | Oil & Gas Operator | Dec 2023 |
| 414 | L & H Energy Co Inc | Knox, PA 16232-4874 | Oil & Gas Operator | Dec 2020 |
| 415 | Lahd Energy Inc | Canton, OH 44709 | Gas Operator | Dec 2009 |
| 416 | Lake Erie Energy Part LLC | Erie, PA 16505-4760 | Oil & Gas Operator | Dec 2012 |
| 417 | Lamar Exploration Corp | Orchard Park, NY 14217 | Gas Operator | Dec 1998 |
| 418 | Langasco Energy Corp | Alliance, OH 44601 | Oil & Gas Operator | Dec 1987 |
| 419 | Laurel Mountain Production | Pittsburgh, PA 15241-1633 | Oil & Gas Operator | Jul 2025 |
| 420 | Leali & Leali Oil Inc | Hermitage, PA 16148-9020 | Oil & Gas Operator | Dec 2016 |
| 421 | Leatherwood, LLC | Canonsburg, PA 15317-6506 | Oil & Gas Operator | Dec 2023 |
| 422 | Leboeuf MFG Inc | Waterford, PA 16441-0458 | Gas Operator | Dec 1990 |
| 423 | Lee E & M Lee Minter | New Kensington, PA 15068-1440 | Gas Operator | Dec 2003 |
| 424 | Lee Lynn MGMT Co | Indiana, PA 15701-3400 | Oil & Gas Operator | Dec 1991 |
| 425 | Lenape Resources Corp | | Oil & Gas Operator | Dec 2000 |
| 426 | Lendrum Energy LLC | Cranberry, PA 16319-4009 | Oil & Gas Operator | Dec 2023 |
| 427 | Lester L Moyer | Cooperstown, PA 16317-2917 | Gas Operator | Dec 2009 |
| 428 | Lightning Oil Co LTD | Mentor, OH 44060-4963 | Gas Operator | Dec 1998 |
| 429 | Lincoln MGMT Co | Greensburg, PA 15601-5200 | Oil & Gas Operator | Dec 2017 |
| 430 | Lindell & Maney | Warren, PA 16365-3643 | Oil & Gas Operator | Dec 2008 |
| 431 | Lindell & Maney LLC | Warren, PA 16365-3670 | Oil & Gas Operator | Dec 2024 |
| 432 | Linn Opr Inc | Indiana, PA 15701-8914 | Oil & Gas Operator | Dec 2007 |
| 433 | Linn Opr LLC | Indiana, PA 15701-8914 | Gas Operator | Dec 2004 |
| 434 | Lion Energy Co LLC | Wexford, PA 15090-6315 | Oil & Gas Operator | Dec 2014 |
| 435 | Loan Asset Issuer LLC, Series 2021 NG-1 | New York, NY 10022 | Oil & Gas Operator | Jul 2025 |
| 436 | Locin Oil Corporation | Katy, TX 77494 | Oil & Gas Operator | Oct 2025 |
| 437 | Lola Energy Petroco LLC | Canonsburg, PA 15317 | Gas Operator | Jul 2025 |
| 438 | LPR Energy, LLC | Dallas, TX 75219 | Oil & Gas Operator | Oct 2025 |
| 439 | LT Oil Co LLC | Pleasantville, PA 16341-0144 | Oil Operator | Dec 2024 |
| 440 | Lulu & Thomas Kavouras | Apollo, PA 15613-1108 | Oil & Gas Operator | Dec 2023 |
| 441 | M & M Royalty LTD | North Canton, OH 44720 | Oil & Gas Operator | Dec 2016 |
| 442 | M4 Energy, LLC | Watsontown, PA 17777-1133 | Oil & Gas Operator | Dec 2024 |
| 443 | Madison Mark T | Marienville, PA 16239-6029 | Oil & Gas Operator | Dec 2012 |
| 444 | Madtick Dev Corp | Punxsutawney, PA 15767-1179 | Oil & Gas Operator | Dec 2024 |
| 445 | Maney McNeal Oil & Gas | | Oil & Gas Operator | Dec 1999 |
| 446 | Manufacturers Light & Heat Co | Pittsburgh, PA 15219 | Gas Operator | Dec 1986 |
| 447 | Manx Inc | Pleasantville, PA 16341-1229 | Oil Operator | Dec 2020 |
| 448 | Maple Grove Enterprises Inc | Rimersburg, PA 16248-6415 | Oil & Gas Operator | Dec 2024 |
| 449 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Aug 2025 |
| 450 | Marco Drilling Inc | Monroeville, PA 15146-0278 | Oil & Gas Operator | Dec 2024 |
| 451 | Margaret Merganser Inc | Tionesta, PA 16353-5853 | Oil & Gas Operator | Dec 2008 |
| 452 | Mark & Troy Johnson | Sugar Grove, PA 16350-5938 | Oil Operator | Dec 2024 |
| 453 | Mark A & Michael J Midlik | Warren, PA 16365-2029 | Oil & Gas Operator | Dec 2015 |
| 454 | Mark Resources Corp | Pittsburgh, PA 15276 | Oil & Gas Operator | Dec 1993 |
| 455 | Marvin Sanders Oil | Sugar Grove, PA 16350-5612 | Oil & Gas Operator | Dec 2016 |
| 456 | Mat Oil & Gas Exploration Inc | Indiana, PA 15701-8931 | Gas Operator | Dec 1993 |
| 457 | Maxson Gas Corp | Shinglehouse, PA 16748-0436 | Oil & Gas Operator | Dec 2024 |
| 458 | Maxson Lawrence C | Shinglehouse, PA 16748 | Oil & Gas Operator | Dec 2016 |
| 459 | Maxwell Bros | Clarion, PA 16214-7446 | Oil & Gas Operator | Dec 2024 |
| 460 | Mays Coal Co | Clarion, PA 16214-0447 | Gas Operator | Dec 2003 |
| 461 | Mays Gas & Coal Co | Clarion, PA 16214-0447 | Oil & Gas Operator | Dec 2024 |
| 462 | MBS Resources Inc | Wilcox, PA 15870-1810 | Oil & Gas Operator | Dec 2024 |
| 463 | MC123 LLC | Indiana, PA 15701-8718 | Gas Operator | Dec 2024 |
| 464 | McCall Carl E | Fairmount City, PA 16224 | Oil & Gas Operator | Dec 2024 |
| 465 | McCluskey J Sterling | New York, NY 10128-1008 | Gas Operator | Dec 1989 |
| 466 | McComb Oil Inc | Stoneboro, PA 16153-3017 | Oil & Gas Operator | Dec 2024 |
| 467 | McCool John E | Youngsville, PA 16371 | Oil & Gas Operator | Jul 2025 |
| 468 | McCoy Natural Gas Co | Oil City, PA 16301-3003 | Gas Operator | Dec 1995 |
| 469 | McKenna Oil Co | Kane, PA 16735-9711 | Oil & Gas Operator | Dec 2004 |
| 470 | MDS Energy Dev LLC | Kittanning, PA 16201-4403 | Oil & Gas Operator | Jul 2025 |
| 471 | MDS Energy LTD | Kittanning, PA 16201-4403 | Gas Operator | Feb 2015 |
| 472 | Mead Oil LLC | Sheffield, PA 16347-1022 | Oil & Gas Operator | Dec 2024 |
| 473 | Medina Res Dev Co LLC | Cambridge Springs, PA 16403-3447 | Oil & Gas Operator | Apr 2025 |
| 474 | Meridian Exploration Corp. | Pittsburgh, PA 15222 | Oil & Gas Operator | Dec 2021 |
| 475 | Meridian Oil & Gas Enterprises Inc | Blairsville, PA 15717-0337 | Oil & Gas Operator | Dec 2003 |
| 476 | Mervin Troyer | Union City, PA 16438-8510 | Gas Operator | Dec 2008 |
| 477 | Mid Amer Natural Resources Inc | Erie, PA 16505-4760 | Gas Operator | Dec 1994 |
| 478 | Mid East Oil Co | Indiana, PA 15701-5378 | Gas Operator | Dec 2006 |
| 479 | Mid-Penn Energy Corporation | Harrisburg, PA 17101-1002 | Gas Operator | Dec 2021 |
| 480 | Mieka LLC | Flower Mound, TX 75028-7446 | Oil & Gas Operator | Dec 2014 |
| 481 | Millennium Oil & Gas Inc | Dexter, KS 67038 | Oil & Gas Operator | Dec 2024 |
| 482 | Minard Run Oil Co | Bradford, PA 16701 | Oil & Gas Operator | Dec 2024 |
| 483 | Minteer & Baker Gas Enterprise | Worthington, PA 16262-0739 | Gas Operator | Dec 2024 |
| 484 | Minter Lee M | Bradford, PA 16701-3763 | Gas Operator | Dec 1991 |
| 485 | Missing Moon Oil Inc | Knox, PA 16232-4507 | Oil & Gas Operator | Dec 2024 |
| 486 | Mitch Well Energy Inc | Waterford, PA 16441-8143 | Oil & Gas Operator | Dec 2012 |
| 487 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 488 | Mob Corp | Waynesburg, PA 15370-2036 | Gas Operator | Dec 2007 |
| 489 | Monona LLC | Ligonier, PA 15658-0612 | Gas Operator | Jul 2025 |
| 490 | Monroe Res LTD | Fairport, NY 14450-3218 | Gas Operator | Dec 2004 |
| 491 | Mount Chestnut Dev LLC | Butler, PA 16002-3940 | Gas Operator | Dec 2017 |
| 492 | MSL Oil & Gas Corp | Bradford, PA 16701-0151 | Oil & Gas Operator | Dec 2024 |
| 493 | MT Savage Refractories | Pittsburgh, PA 15206-0171 | Gas Operator | Dec 2021 |
| 494 | MTN Energy | Aleppo, PA 15310 | Oil & Gas Operator | Jul 2025 |
| 495 | MTN V Oil & Gas Inc | Indiana, PA 15701-8914 | Oil & Gas Operator | Dec 2024 |
| 496 | Murphy Prod Inc | Vanderbilt, PA 15486-1001 | Oil & Gas Operator | Dec 2024 |
| 497 | Mutual Oil & Gas Co | Akron, OH 44311 | Oil & Gas Operator | Dec 2001 |
| 498 | Natl Fuel Gas Supply Corp | Williamsville, NY 14221-5887 | Oil & Gas Operator | Dec 2009 |
| 499 | Natural Energy Dev Corp | Pittsburgh, PA 15241-1548 | Oil & Gas Operator | Dec 2018 |
| 500 | Natural Oil & Gas Corp | Bradford, PA 16701 | Oil & Gas Operator | Dec 2023 |