| 301 | Headington Oil Company | Dallas, TX 75231 | Oil & Gas Operator | Dec 2016 |
| 302 | Heartlands Development Co Inc | Bristow, OK 74010-3826 | Oil & Gas Operator | May 2017 |
| 303 | Heath Oil Co., Inc. | Washington, OK 73093-4702 | Oil & Gas Operator | Apr 2026 |
| 304 | Helton Oil Company | Edmond, OK 73083-7283 | Oil & Gas Operator | Aug 2016 |
| 305 | Heritage Oil Company Inc | Norman, OK 73070 | Oil & Gas Operator | Jul 2008 |
| 306 | Heritage Petroleum, Inc. | Stillwater, OK 74076 | Oil & Gas Operator | Jul 2026 |
| 307 | High Energy | Tulsa, OK 74135 | Oil & Gas Operator | Apr 2026 |
| 308 | Hightower Energy LLC | Cushing, OK 74023-6370 | Oil & Gas Operator | Apr 2026 |
| 309 | Hightower Oil & Gas | Cairo, IL 62914-0401 | Oil Operator | Nov 2014 |
| 310 | Hill Oil Company Inc | Shawnee, OK 74804 | Oil & Gas Operator | Apr 2026 |
| 311 | Hinkle Engineering, Inc. | Oklahoma City, OK 73112 | Oil & Gas Operator | Nov 2016 |
| 312 | Hinkle Oil And Gas Inc | Oklahoma City, OK 73112-4275 | Oil & Gas Operator | May 2026 |
| 313 | HLH Realty Co | Drumright, OK 74030 | Oil & Gas Operator | Mar 2016 |
| 314 | Holke Dave Consulting Inc | Meridian, ID 83646-4812 | Oil & Gas Operator | Apr 2026 |
| 315 | Holloway David A | Okmulgee, OK 74447-9191 | Oil & Gas Operator | Apr 2026 |
| 316 | Holmes Mary Ellen | Bristow, OK 74010 | Oil Operator | Mar 2015 |
| 317 | Hoppes Helen E | Depew, OK 74028-3428 | Oil & Gas Operator | Apr 2015 |
| 318 | Hulsey Larry O & Co | Graham, TX 76046 | Oil & Gas Operator | Jun 2012 |
| 319 | Huntington Energy LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | Jul 2026 |
| 320 | Hyperion Energy LP | Dallas, TX 75206 | Oil & Gas Operator | May 2014 |
| 321 | Imperial Petroleum, Inc. | Evansville, IN 47725 | Oil & Gas Operator | Jan 2005 |
| 322 | Imperium Energy Inc | Atlanta, TX 75551 | Oil & Gas Operator | Apr 2026 |
| 323 | Indian Wells Oil Co | Oklahoma City, OK 73116 | Oil & Gas Operator | Jan 2000 |
| 324 | Indrex Inc | Tulsa, OK 74133 | Oil & Gas Operator | Dec 2000 |
| 325 | Inland Oil Corporation | Sapulpa, OK 74067 | Oil & Gas Operator | May 2026 |
| 326 | Internorth Inc | Tulsa, OK 74136 | Oil & Gas Operator | Apr 2014 |
| 327 | Investment Operating Co | Stillwater, OK 74075-8572 | Oil Operator | Feb 2026 |
| 328 | Iron Sights Operating, Inc. | Stillwater, OK 74076 | Oil & Gas Operator | Jul 2022 |
| 329 | J & T Operating Inc | Norman, OK 73070-1736 | Oil & Gas Operator | Feb 2012 |
| 330 | J A Marrs Oil Company Inc | Drumright, OK 74030 | Oil & Gas Operator | Aug 2024 |
| 331 | J D Operating Company | Tulsa, OK 74105 | Oil & Gas Operator | Jun 2005 |
| 332 | J O C Operating Inc | Fort Worth, TX 76102-6823 | Oil & Gas Operator | Feb 2021 |
| 333 | J.D. Pittman Operating LLC | Edmond, OK 73025 | Oil & Gas Operator | May 2026 |
| 334 | Jai Oil | Lucien, OK 73757 | Oil & Gas Operator | Feb 2026 |
| 335 | James Larry | Guthrie, OK 73044-9622 | Oil & Gas Operator | Apr 2026 |
| 336 | James Lawrence E Estate Of | Crescent, OK 73028-9304 | Oil & Gas Operator | Nov 2021 |
| 337 | James Raymond L | Sapulpa, OK 74066-8785 | Oil & Gas Operator | May 2026 |
| 338 | Jan Oil Company | Oklahoma City, OK 73156 | Oil & Gas Operator | May 2006 |
| 339 | Jay Petroleum Inc | Oklahoma City, OK 73154-0526 | Oil & Gas Operator | Mar 2019 |
| 340 | Jegeroil Corp | New York, NY 10036 | Oil & Gas Operator | Aug 2000 |
| 341 | Jeron Oil And Gas Inc | Denison, TX 75020 | Oil & Gas Operator | Jun 2000 |
| 342 | Jerry Sanner Oil Properties Inc | Enid, OK 73701 | Oil & Gas Operator | May 2026 |
| 343 | Jerry Scott Drilling Company Inc | Ada, OK 74821 | Oil & Gas Operator | Apr 2025 |
| 344 | Jet Oil Co12/Ofb See 18649 | | Oil & Gas Operator | Jul 2007 |
| 345 | JJJ & D Inc | Yale, OK 74085 | Oil Operator | Sep 1998 |
| 346 | Johnson Horace T | Tulsa, OK 74105 | Oil & Gas Operator | Dec 2000 |
| 347 | Joie Oil & Gas Inc | Sapulpa, OK 74067 | Oil & Gas Operator | Dec 1998 |
| 348 | Jones, Mildred J | | Oil & Gas Operator | May 2006 |
| 349 | Judge Ken & Lester | Perkins, OK 74059 | Oil & Gas Operator | Aug 2014 |
| 350 | K & E Field Services Inc | Bartlesville, OK 74005-0518 | Oil & Gas Operator | Jun 2016 |
| 351 | K & M Oil Company LLC | Hennessey, OK 73742 | Oil & Gas Operator | May 2026 |
| 352 | K S Oil Company Inc | Norman, OK 73072-7480 | Oil & Gas Operator | May 2026 |
| 353 | Kahn George Operating Co | Seminole, OK 74818 | Oil & Gas Operator | Nov 2000 |
| 354 | Kanokla Oil & Gas Corporation | Wellington, KS 67152-0444 | Oil & Gas Operator | Apr 2026 |
| 355 | Kantor Oil Company LLC | Tulsa, OK 74136 | Oil & Gas Operator | Apr 2026 |
| 356 | Kato Operating Company | Bristow, OK 74010 | Oil & Gas Operator | Mar 2015 |
| 357 | Keener Oil & Gas Company | Tulsa, OK 74119-4416 | Oil & Gas Operator | May 2026 |
| 358 | Keener Oil Company | Tulsa, OK 74103 | Oil & Gas Operator | Feb 2018 |
| 359 | Keith F Walker Oil & Gas Company LLC | Oklahoma City, OK 73114 | Oil & Gas Operator | May 2026 |
| 360 | Kelly Jr Walter A Opr Co | Stillwater, OK 74076 | Oil & Gas Operator | Apr 2014 |
| 361 | Kemp Roy L | | Oil Operator | Jan 2011 |
| 362 | Keno Oil & Gas Inc | Hennessey, OK 73742 | Oil & Gas Operator | Jan 1995 |
| 363 | Kerr-McGee Corporation | Dallas, TX 75380 | Oil & Gas Operator | Feb 2026 |
| 364 | Kiska Oil Company | Tulsa, OK 74114 | Oil & Gas Operator | Jan 2019 |
| 365 | Klo LLC | Tulsa, OK 74120-2428 | Oil & Gas Operator | May 2026 |
| 366 | Knife Oil Company Inc | Cushing, OK 74023-1347 | Oil & Gas Operator | Aug 2000 |
| 367 | Koby Oil Company LLC | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2026 |
| 368 | Koch Oil Company | | Oil & Gas Operator | May 2017 |
| 369 | Kopco Inc | Caney, KS 67333 | Oil & Gas Operator | Oct 2025 |
| 370 | KWB Oil Property Management Inc | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2026 |
| 371 | Lackey Raymond R | Lindsay, OK 73052 | Oil & Gas Operator | Jun 2015 |
| 372 | Lackey Raymond R & Assoc | Sulphur, OK 73086 | Oil & Gas Operator | Apr 2026 |
| 373 | Laguna Petroleum Corporation | Houston, TX 77046 | Oil & Gas Operator | Jul 2026 |
| 374 | Lakeshore Operating, LLC | Wichita, KS 67203 | Oil & Gas Operator | Jul 2026 |
| 375 | Lamamco Drilling Company | Skiatook, OK 74070 | Oil & Gas Operator | Apr 2026 |
| 376 | Lance Ruffel Oil & Gas LLC | Oklahoma City, OK 73102-5632 | Oil & Gas Operator | May 2026 |
| 377 | Landers & Musgrove | Okemah, OK 74859 | Oil & Gas Operator | Mar 2015 |
| 378 | Landers & Waldman Inc | Okemah, OK 74859-0660 | Oil & Gas Operator | May 2013 |
| 379 | Landmark Energy LLC | Seminole, OK 74868 | Oil & Gas Operator | May 2026 |
| 380 | Lapetco Inc | Plano, TX 75093 | Oil & Gas Operator | Aug 2024 |
| 381 | Lariat Petroleum Inc | Tulsa, OK 74119 | Oil & Gas Operator | Sep 2024 |
| 382 | Larkspur Operating LLC | Oklahoma City, OK 73106 | Oil & Gas Operator | May 2026 |
| 383 | Larry Wolff Dba Wolff'S Oilfield Service | Cushing, OK 74023-9789 | Oil & Gas Operator | Apr 2026 |
| 384 | Las Colinas Oil Corp. | Irving, TX 75062 | Oil & Gas Operator | Mar 2015 |
| 385 | Lauck & Associates | Walnut Creek, CA 91789 | Oil & Gas Operator | May 2026 |
| 386 | Laughlin Jack D | Cushing, OK 74023 | Oil & Gas Operator | Sep 2016 |
| 387 | Laurel Operating Company | Stillwater, OK 74074-3025 | Oil & Gas Operator | Apr 2026 |
| 388 | Le Norman Energy Corporation | Duncan, OK 73534 | Oil & Gas Operator | Nov 2014 |
| 389 | Leavell Resources Corporation | Hays, KS 67601 | Oil & Gas Operator | Mar 2015 |
| 390 | Leeman Energy Corporation | Oklahoma City, OK 73118-1802 | Oil & Gas Operator | Mar 2015 |
| 391 | Legacy - M & K Corporation | Dallas, TX 75231-0969 | Oil & Gas Operator | Jan 2025 |
| 392 | Legacy Energy Services LLC | Stillwater, OK 74074 | Oil & Gas Operator | May 2026 |
| 393 | Legend Energy Corporation | Stillwater, OK 74074-1721 | Oil & Gas Operator | Aug 2022 |
| 394 | Leigh Operating Co | Dallas, TX 75205 | Oil & Gas Operator | Mar 2008 |
| 395 | Lema Petroleum Inc | Seminole, OK 74868 | Oil & Gas Operator | May 2026 |
| 396 | Levinson Partners Corporation | Denver, CO 80202 | Oil & Gas Operator | Jul 1995 |
| 397 | Lewis Oil Corp. | Stillwater, OK 74076 | Oil & Gas Operator | Apr 2026 |
| 398 | Liberty Operating Inc | Norman, OK 73069-8225 | Oil & Gas Operator | Dec 2024 |
| 399 | Lion Petroleum Company | Oklahoma City, OK 73120-4503 | Oil & Gas Operator | Aug 2015 |
| 400 | Little Oil Company LLC | Cushing, OK 74023 | Oil Operator | Apr 2026 |