| 401 | Ferguson Energy Inc | Evanston, WY 82930 | Oil & Gas Operator | Dec 2025 |
| 402 | Ferguson Oil Company Inc | | Oil & Gas Operator | Apr 1994 |
| 403 | Ferreira Oil Properties LLC | Carefree, AZ 85377 | Oil Operator | Apr 2014 |
| 404 | Fidelity Exploration & Production Company | Denver, CO 80203 | Oil & Gas Operator | Jun 2026 |
| 405 | Fina Oil And Chemical Company | Dallas, TX 75221 | Oil & Gas Operator | May 2019 |
| 406 | Finaly Resources LLC | Sunset Beach, CA 90742 | Oil & Gas Operator | Jul 2026 |
| 407 | Finley Resources Inc | Fort Worth, TX 76113 | Oil & Gas Operator | Jul 2026 |
| 408 | First Energy Corporation | | Oil & Gas Operator | Jun 1993 |
| 409 | First Energy Properties | Houston, TX 77060 | Oil & Gas Operator | Dec 1986 |
| 410 | First Sourcenergy Wyoming Inc | Gillette, WY 82718 | Gas Operator | Jul 2003 |
| 411 | Five States Operating Company LLC | Dallas, TX 75206 | Oil & Gas Operator | May 2026 |
| 412 | Flag-Redfern Oil Company | Oklahoma City, OK 73125 | Oil & Gas Operator | Jul 2002 |
| 413 | Flahive Oil & Gas LLC | Golden, CO 80401 | Oil Operator | Oct 1995 |
| 414 | Florida Gas Exploration Co | | Oil & Gas Operator | Feb 1985 |
| 415 | Flow Production Company | Midland, TX 79708 | Oil & Gas Operator | Mar 2005 |
| 416 | Flying J Oil & Gas Inc | North Salt Lake, UT 84054 | Oil & Gas Operator | Dec 2009 |
| 417 | FMC Corporation | Green River, WY 82935 | Oil & Gas Operator | Dec 2008 |
| 418 | Forcenergy Inc | Miami, FL 33129 | Oil & Gas Operator | Mar 2015 |
| 419 | Forcenergy Onshore Inc. | Houston, TX 77002 | Oil & Gas Operator | Dec 2012 |
| 420 | Foree R L | Dallas, TX 75225 | Oil & Gas Operator | Aug 2001 |
| 421 | Foreland Resources LLC | Lakewood, CO 80228 | Oil & Gas Operator | Oct 2025 |
| 422 | Forest Oil Permian Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 423 | Forestar Petroleum Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2017 |
| 424 | Fossil Creek Resources LLC | Arlington, TX 76011-5597 | Oil & Gas Operator | Mar 2015 |
| 425 | Fossil Energy Inc | Austin, TX 78746 | Oil & Gas Operator | Jul 2026 |
| 426 | Foundation Energy Managment LLC | Addison, TX 74119 | Oil & Gas Operator | Nov 2025 |
| 427 | Four-A Energy LLC | Cody, WY 82414 | Oil Operator | May 2026 |
| 428 | Frank Louis L | Kingsville, TX 78364 | Oil & Gas Operator | Aug 2003 |
| 429 | Fremont Energy Corporation | Oklahoma City, OK 73112 | Oil & Gas Operator | Dec 2004 |
| 430 | Frickey Investment MGT Co LLC | Lakewood, CO 80215 | Oil & Gas Operator | Jun 2026 |
| 431 | Fruehauf LLC | Gaylord, MI 49735 | Oil Operator | Feb 2005 |
| 432 | Fuel Exploration Inc | Denver, CO 80295 | Oil & Gas Operator | Jan 1992 |
| 433 | Fuel Resources Development Co | Denver, CO 80202 | Oil & Gas Operator | Feb 1994 |
| 434 | H & H Star Energy Inc | Traverse City, MI 49684 | Oil & Gas Operator | Aug 2016 |
| 435 | H & M Oil Producers | Littleton, CO 80160 | Oil & Gas Operator | Apr 2000 |
| 436 | H & R Oil Company | | Oil & Gas Operator | Dec 2000 |
| 437 | H & R Well Services, Inc. | FT Morgan, CO 80701 | Oil & Gas Operator | Apr 2015 |
| 438 | H C M Energy LLC | Billings, MT 59102 | Oil Operator | Jul 2003 |
| 439 | H D Oil Company | Thermopolis, WY 82443 | Oil Operator | Feb 2026 |
| 440 | H G H Oil Company | | Oil Operator | Dec 1990 |
| 441 | H2oil Services LLC | | Oil Operator | May 2026 |
| 442 | Hadley/Jackson Energy LLC | Lake Forest, IL 60045 | Oil & Gas Operator | May 2026 |
| 443 | Hadson Petroleum Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2015 |
| 444 | Hallador Petroleum LLP | Denver, CO 80264 | Oil & Gas Operator | Feb 2019 |
| 445 | Hallwood Petroleum | Denver, CO 80237 | Oil & Gas Operator | Dec 1997 |
| 446 | Hamon Jake L | Dallas, TX 75201-3902 | Oil & Gas Operator | Nov 1997 |
| 447 | Hanson Operating Company Inc | Roswell, NM 88202 | Oil & Gas Operator | Apr 2026 |
| 448 | Harpel John P Jr | FT. Collins, CO 80525 | Oil & Gas Operator | May 1998 |
| 449 | Harper Oil Co. | Denver, CO 80217 | Oil & Gas Operator | Mar 2026 |
| 450 | Harrell Oil Company LLC | Ardmore, OK 73402 | Oil Operator | Jan 2025 |
| 451 | Harvey E Yates Company | Roswell, NM 88202 | Oil & Gas Operator | Feb 2015 |
| 452 | Haug Lawrence | Kimball, NE 69145 | Oil & Gas Operator | Jul 2007 |
| 453 | Havoco Inc | Newcastle, WY 82701 | Oil & Gas Operator | Aug 2005 |
| 454 | Hawks Company | Casper, WY 82602 | Oil & Gas Operator | Apr 2007 |
| 455 | Hawks Industries Inc | Casper, WY 82601 | Oil & Gas Operator | Jun 1993 |
| 456 | Hay Leonard | Rock Springs, WY 82901 | Oil & Gas Operator | Sep 1994 |
| 457 | Headington Oil Company, L.P. | Dallas, TX 75231 | Oil & Gas Operator | Mar 2008 |
| 458 | Heartland Energy Company | Big Horn, WY 82833 | Gas Operator | Jun 2012 |
| 459 | Hedges Spencer | Casper, WY 82604 | Oil Operator | Mar 2024 |
| 460 | Helena Resources Inc | Lakewood, CO 80215 | Oil & Gas Operator | Apr 2026 |
| 461 | Helis Oil & Gas Company LLC Estate | New Orleans, LA 70130 | Oil & Gas Operator | Jul 2022 |
| 462 | Henderson Petroleum Corp | San Angelo, TX 76906 | Oil & Gas Operator | Jul 2013 |
| 463 | Herbaly Petroleum Corp | FT Worth, TX 76102 | Oil & Gas Operator | Feb 2002 |
| 464 | Hershey Oil Corporation | | Oil & Gas Operator | Jul 1992 |
| 465 | Hesperus Energy II LLC | | Oil Operator | Jan 2026 |
| 466 | Hi-Pro Production | Gillette, WY 82717 | Gas Operator | Nov 2003 |
| 467 | High Plains Gas LLC | Gillette, WY 82717 | Gas Operator | Aug 2014 |
| 468 | High Summit Oil & Gas Inc | | Oil & Gas Operator | Sep 1987 |
| 469 | Highland Exploration | | Oil Operator | Sep 1979 |
| 470 | Hilcorp Energy Company | Houston, TX 77208 | Oil & Gas Operator | Jul 2026 |
| 471 | Hilliard Oil & Gas, Inc. | New Orleans, LA 70112 | Oil & Gas Operator | May 2001 |
| 472 | HMX Investments, Inc. | Katy, TX 77494 | Oil & Gas Operator | Apr 2026 |
| 473 | HNG Oil Company | | Oil & Gas Operator | Jun 1987 |
| 474 | Hodge T F | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2007 |
| 475 | Hoff Elmer & Mildred | | Oil & Gas Operator | Jan 1991 |
| 476 | Holden Harold B | Billings, MT 59103 | Oil Operator | Jun 1996 |
| 477 | Holly Energy Inc | | Oil Operator | Apr 1983 |
| 478 | Holwell Drilling Company | | Oil Operator | Sep 1992 |
| 479 | Home Petroleum Corp | Victoria, TX 77902 | Oil & Gas Operator | Jul 2026 |
| 480 | Hondo Oil & Gas | Houston, TX 77042 | Oil & Gas Operator | Oct 1995 |
| 481 | Hot Springs Resources LTD | Casper, WY 82601 | Oil Operator | Dec 2014 |
| 482 | Houston Oil And Minerals | | Oil & Gas Operator | Oct 1993 |
| 483 | Howell Petroleum Corporation | Houston, TX 77251 | Oil & Gas Operator | Oct 2015 |
| 484 | HR Energy LLC | Shelby, MT 59474 | Oil & Gas Operator | Apr 2026 |
| 485 | HRM Resources II, LLC | Denver, CO 80202 | Oil & Gas Operator | Mar 2026 |
| 486 | HRM Resources III LLC | Denver, CO 80202 | Oil & Gas Operator | Jun 2022 |
| 487 | HRM Resources LLC | Denver, CO 80202 | Oil & Gas Operator | Aug 2015 |
| 488 | Hrubetz Oil Co. | Dallas, TX 75225 | Oil Operator | Sep 1986 |
| 489 | HS Resources, Inc. | Denver, CO 80202 | Oil & Gas Operator | Sep 2002 |
| 490 | Huber J M Corp | Edison, NJ 08837 | Oil & Gas Operator | Jul 2026 |
| 491 | Hudson Group LLC | Casper, WY 82601 | Oil & Gas Operator | Jul 2025 |
| 492 | Hughes Oil Company Inc | Odessa, TX 79765 | Oil & Gas Operator | Feb 2004 |
| 493 | Hugoton Energy Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Dec 2019 |
| 494 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Jul 2026 |
| 495 | Hunt Petroleum (Aec), Inc. | Dallas, TX 75201 | Oil & Gas Operator | Nov 2008 |
| 496 | Huntington Energy LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | Jul 2026 |
| 497 | Hurley Oil Company | | Oil Operator | Dec 1988 |
| 498 | Husky Oil Company | Cody, WY 82414 | Oil & Gas Operator | Dec 1984 |
| 499 | Hyco Oil Inc | Newcastle, WY 82701 | Oil & Gas Operator | Dec 2006 |
| 500 | Hydrocarbon Management, Inc. | San Antonio, TX 78216 | Oil & Gas Operator | Dec 1996 |