| 301 | Halliburton Oil Producing Co. | Duncan, OK 73534 | Oil & Gas Operator | Apr 2016 |
| 302 | Hallwood Petroleum, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jan 2025 |
| 303 | Hardwick Oil Company | Sugar Land, TX 77478 | Oil & Gas Operator | Nov 2014 |
| 304 | Harrell Petroleum Inc | Oklahoma City, OK 73102-7201 | Oil & Gas Operator | Oct 2017 |
| 305 | Harrell Verlan W | Oklahoma City, OK 73102-7201 | Oil & Gas Operator | Nov 1999 |
| 306 | Harris Oil & Gas Company | Denver, CO 80202 | Oil & Gas Operator | Jun 2016 |
| 307 | Harrison Oil & Gas Inc | Houston, TX 77019 | Oil & Gas Operator | Jun 2025 |
| 308 | Harrod Leasing | Edmond, OK 73034 | Oil & Gas Operator | Jun 2025 |
| 309 | Hawkins & Hawkins | Council Hill, OK 74428 | Oil & Gas Operator | Jul 1996 |
| 310 | Hawkins & Son Inc | Boynton, OK 74422 | Oil & Gas Operator | Aug 2019 |
| 311 | Haynes Jim L & Betty L | Haskell, OK 74436-8803 | Oil & Gas Operator | Dec 2013 |
| 312 | HCG Energy Corporation & Subs | | Oil & Gas Operator | Mar 2015 |
| 313 | Headington Oil Company | Dallas, TX 75231 | Oil & Gas Operator | Dec 2016 |
| 314 | Heartland Exploration Inc | Edmond, OK 73013 | Oil & Gas Operator | Dec 2015 |
| 315 | Hendrickson W R | Beggs, OK 74421-2936 | Oil & Gas Operator | Jun 2023 |
| 316 | Henry Oil & Gas Inc | Oklahoma City, OK 73127 | Oil & Gas Operator | Jul 2009 |
| 317 | Henson Doyle | Okmulgee, OK 74447-4841 | Oil & Gas Operator | Jun 2020 |
| 318 | Henson Terry Dba Daycon Exploration | Tulsa, OK 74137-3546 | Oil & Gas Operator | Jun 2025 |
| 319 | Heritage Petroleum, Inc. | Stillwater, OK 74076 | Oil & Gas Operator | Sep 2025 |
| 320 | Highmark Energy Operating, LLC | Dallas, TX 75222 | Oil & Gas Operator | Sep 2025 |
| 321 | Hill Oil Company Inc | Shawnee, OK 74804 | Oil & Gas Operator | Jun 2025 |
| 322 | Himco Oil & Gas, Inc. | Enid, OK 73702 | Oil & Gas Operator | Jun 2025 |
| 323 | Holke Dave Consulting Inc | Meridian, ID 83646-4812 | Oil & Gas Operator | Jun 2025 |
| 324 | Holman Ray | Okemah, OK 74859-0029 | Gas Operator | May 2024 |
| 325 | Homer Oil Co LLC | Holdenville, OK 74848-3232 | Oil Operator | Jun 2025 |
| 326 | Hosco Operating Inc | Seminole, OK 74868-2447 | Oil & Gas Operator | Aug 2017 |
| 327 | Howden Petroleum Corp | Wetumka, OK 74883 | Gas Operator | Nov 1997 |
| 328 | Howell Bill J | Calvin, OK 74531-0248 | Oil & Gas Operator | Sep 2016 |
| 329 | HP Operating LLC | Seminole, OK 74868 | Oil Operator | Jun 2025 |
| 330 | HRC Production Co | Houston, TX 77024 | Oil & Gas Operator | May 2025 |
| 331 | HRF Exploration & Production LLC | Gaylord, MI 49734-0160 | Gas Operator | Sep 2025 |
| 332 | Huber Energy Panhandle LP | Houston, TX 77079 | Oil & Gas Operator | Oct 2005 |
| 333 | Hughes Drilling Co. | Enid, OK 73702 | Oil & Gas Operator | Apr 1998 |
| 334 | Hughes Gas Systems LLC | Dallas, TX 75214 | Oil & Gas Operator | Jun 2025 |
| 335 | Hunton Oil & Gas Corporation | Oklahoma City, OK 73154-0191 | Oil & Gas Operator | May 2019 |
| 336 | Hunton Operating LLC | Oklahoma City, OK 73154 | Oil & Gas Operator | Jun 2025 |
| 337 | Husky Ventures Inc | Oklahoma City, OK 73134 | Oil & Gas Operator | Jun 2025 |
| 338 | Hutton Gas Operating Company | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2015 |
| 339 | Igleheart Warren | Edmond, OK 73034-8964 | Oil & Gas Operator | Jun 2016 |
| 340 | Ike Energy LLC | Stillwater, OK 74074-1745 | Oil & Gas Operator | Jul 2025 |
| 341 | Integrated Energy Service Corp | Cleveland, OK 74020 | Oil & Gas Operator | Nov 1998 |
| 342 | International Energy Corporation | Tulsa, OK 74136-3922 | Oil & Gas Operator | Dec 2018 |
| 343 | Investment Equipment LLC | FT Morgan, CO 80701 | Oil & Gas Operator | Jul 2025 |
| 344 | J & P Production | Holdenville, OK 74848-9485 | Oil Operator | Mar 2015 |
| 345 | J & R Enterprises | Wetumka, OK 74883-0068 | Oil & Gas Operator | Sep 2000 |
| 346 | J & Z Investments LLC | Ada, OK 74820-0065 | Oil & Gas Operator | Jun 2025 |
| 347 | J.R. Oil Company | Houston, TX 77007 | Oil & Gas Operator | Jul 2019 |
| 348 | J3 Energy LLC | Ada, OK 74820 | Oil Operator | Jun 2025 |
| 349 | Jackson Energy Development, Inc. | Cedar Park, TX 78613 | Oil & Gas Operator | Sep 2025 |
| 350 | Jackson L B Production Co | Tulsa, OK 74193-0001 | Oil & Gas Operator | Aug 2013 |
| 351 | James Oil Company | Compton, CA 90221-4399 | Oil & Gas Operator | Nov 2008 |
| 352 | January Investments LLC | Norman, OK 73069-8224 | Oil & Gas Operator | Jul 2025 |
| 353 | Jasper Oil LLC | Bristow, OK 74010-3907 | Oil & Gas Operator | Jun 2025 |
| 354 | Jay Petroleum Inc | Oklahoma City, OK 73154-0526 | Oil & Gas Operator | Mar 2019 |
| 355 | Jefferson Co LLC (The) | Corinth, TX 76205 | Oil & Gas Operator | Aug 2004 |
| 356 | Jericho Exploration | Weleetka, OK 74880-0704 | Oil & Gas Operator | Jun 2025 |
| 357 | Jerry Scott Drilling Company Inc | Ada, OK 74821 | Oil & Gas Operator | Apr 2025 |
| 358 | Jetson Operating Inc | Ada, OK 74820 | Oil & Gas Operator | Sep 2024 |
| 359 | Jma Energy Company, LLC | Oklahoma City, OK 73118 | Oil & Gas Operator | Jul 2025 |
| 360 | Johnson Doyle T | Oklahoma City, OK 73118-1007 | Oil & Gas Operator | Jan 2013 |
| 361 | Joie Oil & Gas Inc | Sapulpa, OK 74067 | Oil & Gas Operator | Dec 1998 |
| 362 | Jolen Operating Company | Oklahoma City, OK 73102 | Oil & Gas Operator | Jun 2025 |
| 363 | Jones Douglas Q LLC | Fort Gibson, OK 74434 | Oil Operator | Aug 2021 |
| 364 | Jones Energy LLC | Oklahoma City, OK 73134 | Oil & Gas Operator | Jun 2025 |
| 365 | Jordan Oil & Gas | Fort Smith, AR 72903-4975 | Oil & Gas Operator | Sep 2004 |
| 366 | Jordan Oil & Gas Company | Healdsburg, CA 95448-1919 | Oil & Gas Operator | Mar 1995 |
| 367 | Joshua Energy LLC | Tulsa, OK 74134-7460 | Gas Operator | Jun 2025 |
| 368 | Josie Oil & Gas Inc | Seminole, OK 74818-0134 | Oil & Gas Operator | Mar 2015 |
| 369 | Jvo Petroleum Inc | Shawnee, OK 74801 | Oil & Gas Operator | Jul 1995 |
| 370 | K & H Oil Company | Oklahoma City, OK 73112 | Oil & Gas Operator | Dec 1995 |
| 371 | K Energy Inc | Mannford, OK 74044-3023 | Oil & Gas Operator | May 2013 |
| 372 | K S & S Oil Company Inc | Terral, TX 73569-5056 | Oil Operator | Jun 2025 |
| 373 | K S Oil Company Inc | Norman, OK 73072-7480 | Oil & Gas Operator | Jun 2025 |
| 374 | Kahan And Associates, Inc | Tulsa, OK 74170 | Oil & Gas Operator | Jul 2025 |
| 375 | Kahan Louis | Tulsa, OK 74101 | Oil & Gas Operator | May 1994 |
| 376 | Kaiser-Francis Oil Company | Tulsa, OK 74121 | Oil & Gas Operator | Sep 2025 |
| 377 | Kana Resources, Inc. | Dallas, TX 75243 | Oil & Gas Operator | Aug 2003 |
| 378 | Karbuhn Oil Company | Tomball, TX 77375 | Oil & Gas Operator | Sep 2025 |
| 379 | Kato Operating Company | Bristow, OK 74010 | Oil & Gas Operator | Mar 2015 |
| 380 | Kay Production Company Inc | Seminole, OK 74868 | Oil & Gas Operator | Jun 2025 |
| 381 | KCS Resources LLC | Houston, TX 77027 | Oil & Gas Operator | Feb 2017 |
| 382 | Keener Oil & Gas Company | Tulsa, OK 74119-4416 | Oil & Gas Operator | Jul 2025 |
| 383 | Keener Oil Company | Tulsa, OK 74103 | Oil & Gas Operator | Feb 2018 |
| 384 | Keesee Paul Inc | Holdenville, OK 74848 | Oil & Gas Operator | Nov 1998 |
| 385 | Kelley Oil & Gas | McAlester, OK 74570 | Oil & Gas Operator | May 2013 |
| 386 | Kelloil Inc | Fort Worth, TX 76116-5600 | Oil & Gas Operator | Mar 2015 |
| 387 | Kelly Cook Oil LLC | Shawnee, OK 74804-3148 | Oil & Gas Operator | Jun 2025 |
| 388 | Kemp Roy L | | Oil Operator | Jan 2011 |
| 389 | Ken Snyder Inc | Newalla, OK 74857-7107 | Oil & Gas Operator | Jun 2025 |
| 390 | Kendol Exploration Inc | Oklahoma City, OK 73105-2513 | Oil & Gas Operator | Mar 2025 |
| 391 | Kerr McGee Rocky MTN Corp | Denver, CO 80202-5736 | Oil & Gas Operator | Mar 2015 |
| 392 | Kimco Oil And Gas | Wewoka, OK 74884-0613 | Oil & Gas Operator | Jul 2016 |
| 393 | Kingdom Resources Inc | Frisco, TX 75033-3673 | Oil & Gas Operator | Jun 2023 |
| 394 | Kingery Drilling Co., Inc. | Ardmore, OK 73402 | Oil & Gas Operator | Jun 2025 |
| 395 | Klo LLC | Tulsa, OK 74120-2428 | Oil & Gas Operator | Jul 2025 |
| 396 | KN Production Co. | Lakewood, CO 80228 | Oil & Gas Operator | Jun 2003 |
| 397 | Koch Oil Company | | Oil & Gas Operator | May 2017 |
| 398 | Kodiak Oil & Gas Inc | Muenster, TX 76252 | Oil & Gas Operator | Sep 2025 |
| 399 | Krumme Oil Company LLP | Bristow, OK 74010 | Oil & Gas Operator | Jun 2025 |
| 400 | Ky Oil Co | Palco, KS 67657 | Oil & Gas Operator | Aug 2000 |