| 4201 | Okmar Oil Company | Marietta, OH 45750 | Oil & Gas Operator | Jun 2005 |
| 4202 | Okt Petroleum Company Inc | Oklahoma City, OK 73118-7425 | Oil & Gas Operator | Oct 2013 |
| 4203 | Oktex Operating LLC | Edmond, OK 73013-1961 | Oil & Gas Operator | May 2020 |
| 4204 | Oky Investments, Inc. | Edmond, OK 73013 | Oil & Gas Operator | Sep 2021 |
| 4205 | Old Dominion Oil Corporation | Oklahoma City, OK 73107 | Oil & Gas Operator | Apr 2009 |
| 4206 | Ole Crow Operating | Wichita Falls, TX 76308 | Oil Operator | Mar 2025 |
| 4207 | Oleum Incorporated | | Oil & Gas Operator | Mar 1996 |
| 4208 | Olia Oil & Gas Services LLC | Cedar Park, TX 78630-2049 | Oil & Gas Operator | Aug 2022 |
| 4209 | Oliphant Gertrud | Holdenville, OK 74848-0849 | Oil Operator | Aug 2013 |
| 4210 | Oliphant Operating Co,LTD,LLC | | Oil Operator | Mar 2025 |
| 4211 | Olive Oil & Gas Inc | Jennings, OK 74052 | Oil & Gas Operator | Mar 2025 |
| 4212 | Olympia Oil Inc | Edmond, OK 73083-7088 | Oil & Gas Operator | Jul 2020 |
| 4213 | Olympic Petroleum Company | Tulsa, OK 74114 | Oil & Gas Operator | Jun 1998 |
| 4214 | Omega Energy, LLC | Corpus Chrsti, TX 78418 | Oil & Gas Operator | Jun 2025 |
| 4215 | Omimex International Corp | Fort Worth, TX 76103-2300 | Oil & Gas Operator | Mar 2025 |
| 4216 | Omimex Petroleum Inc | Fort Worth, TX 76120 | Oil & Gas Operator | Aug 2022 |
| 4217 | Omni Oil & Gas, Inc. | San Antonio, TX 78229 | Oil & Gas Operator | Oct 2017 |
| 4218 | On-Line Oil Inc | Oklahoma City, OK 73105-5208 | Oil & Gas Operator | Mar 2015 |
| 4219 | Onapa Gas Company LLC | Tulsa, OK 74136-7253 | Gas Operator | Nov 2019 |
| 4220 | Oneok Exploration Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 4221 | Oneok Field Services Company | Tulsa, OK 74103 | Oil & Gas Operator | Jul 2022 |
| 4222 | Oneok Gas Processing LLC | Tulsa, OK 74103 | Oil & Gas Operator | May 2018 |
| 4223 | Oneok Gas Transportation Co | Tulsa, OK 74121-2089 | Oil & Gas Operator | Oct 2014 |
| 4224 | Oneok Resources Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 4225 | Onpoint Oil & Gas LLC | Oklahoma City, OK 73170-4848 | Oil & Gas Operator | Mar 2025 |
| 4226 | Onshore Royalties LLC | Houston, TX 77269 | Oil & Gas Operator | Apr 2025 |
| 4227 | Onyx Energy Corporation | Oklahoma City, OK 73157 | Oil & Gas Operator | May 1994 |
| 4228 | Onyx Properties Corp | Oklahoma City, OK 73114 | Oil & Gas Operator | May 2006 |
| 4229 | Opal Operating Company LLC | Oklahoma City, OK 73142 | Oil & Gas Operator | Jun 2025 |
| 4230 | Open Door Holdings Inc | Surprise, AZ 85387-2015 | Oil & Gas Operator | Feb 2024 |
| 4231 | Open Door Productions Inc | Muskogee, OK 74401-1032 | Oil & Gas Operator | Apr 2020 |
| 4232 | Open Range Energy LLC | Jones, OK 73049-8744 | Oil & Gas Operator | Mar 2025 |
| 4233 | Optima Exploration LLC | Tulsa, OK 74116-5664 | Oil & Gas Operator | Mar 2015 |
| 4234 | Opubco Resources Of TX Inc | Dallas, TX 75231 | Oil & Gas Operator | Sep 2005 |
| 4235 | Oracle Resources Oklahoma LP | Dallas, TX 75240-5751 | Oil & Gas Operator | Feb 2008 |
| 4236 | Orason Resources Inc | Tulsa, OK 74169-1225 | Oil & Gas Operator | Nov 2006 |
| 4237 | Orca Operating Company LLC | Houston, TX 77056 | Oil & Gas Operator | Apr 2025 |
| 4238 | Oren Stone | Erick, OK 73645-4542 | Gas Operator | Jun 2022 |
| 4239 | Orion Exploration LLC | Tulsa, OK 74105-5153 | Oil & Gas Operator | Apr 2015 |
| 4240 | Orion Exploration Partners LLC | Tulsa, OK 74105-5153 | Oil & Gas Operator | Jan 2025 |
| 4241 | Orloski John C | Bartlesville, OK 74006 | Oil & Gas Operator | Mar 2025 |
| 4242 | Osa Oil & Gas LLC | Tulsa, OK 74131 | Oil & Gas Operator | Aug 2023 |
| 4243 | Osage Energy Resources LLC | Bartlesville, OK 74005-2527 | Oil & Gas Operator | Mar 2025 |
| 4244 | Osage Exploration & Development Inc | San Diego, CA 92131-3807 | Oil & Gas Operator | Oct 2016 |
| 4245 | Osage Oil & Transportation Inc | Cleveland, OK 74020 | Oil & Gas Operator | Nov 2000 |
| 4246 | Osage Petroleum Corporation | Saint Louis, MO 63131-4691 | Oil & Gas Operator | Mar 2009 |
| 4247 | Osborn Heirs Co | San Antonio, TX 78217 | Oil & Gas Operator | Mar 2025 |
| 4248 | Osburn Gerald Dba Ozzy & Son Oil & Gas | Drumright, OK 74030-5467 | Oil Operator | Oct 2020 |
| 4249 | Oscar'S Well Service Inc | Okemah, OK 74859 | Oil & Gas Operator | Apr 1998 |
| 4250 | Oshtah Oil Company LLC | Stratford, OK 74872 | Oil & Gas Operator | Sep 2018 |
| 4251 | Oso Resources LLC | Oklahoma City, OK 73118-5022 | Oil & Gas Operator | Mar 2025 |
| 4252 | Osterhout Phillip L | Drumright, OK 74030-0693 | Oil & Gas Operator | Jan 2014 |
| 4253 | Oswego Arbuckle Enterprise Inc | S Coffeyville, OK 74072-9702 | Oil & Gas Operator | Mar 2015 |
| 4254 | Otc Investors Inc | | Oil Operator | Jan 2025 |
| 4255 | Otc Petroleum Corporation | Nichols Hill, OK 73116 | Oil & Gas Operator | Mar 2015 |
| 4256 | Otc/Occ Not Assigned | | Oil & Gas Operator | Dec 2024 |
| 4257 | Ouachita Exploration Inc | Chickasha, OK 73018 | Oil & Gas Operator | Mar 2025 |
| 4258 | Outback Petroleum Inc | Moore, OK 73160-9998 | Oil & Gas Operator | Mar 2015 |
| 4259 | Ovation Energy II, LP | Houston, TX 77279 | Oil & Gas Operator | Jun 2011 |
| 4260 | Ovation Energy, LP | N Richlnd HLS, TX 76180 | Oil & Gas Operator | Sep 2004 |
| 4261 | Overflow Energy Stack LLC | Booker, TX 79005 | Oil Operator | Sep 2022 |
| 4262 | Overflow Energy, LLC | Booker, TX 79005 | Oil & Gas Operator | Jun 2025 |
| 4263 | Overland Investments Inc | Coweta, OK 74429 | Oil & Gas Operator | Mar 2025 |
| 4264 | Ovintiv Mid-Continent Inc. | The Woodlands, TX 77380-2764 | Oil & Gas Operator | Apr 2025 |
| 4265 | Ovintiv USA Inc. | Denver, CO 80202 | Oil & Gas Operator | Jun 2025 |
| 4266 | Owens James W | Tulsa, OK 74114-1425 | Oil & Gas Operator | Oct 2022 |
| 4267 | Owl Creek Production Co., Inc. | Houston, TX 77027 | Oil & Gas Operator | Apr 2006 |
| 4268 | Oxco, LLC | | Oil & Gas Operator | Feb 2015 |
| 4269 | Oxford Exploration Company | Denver, CO 80237 | Oil & Gas Operator | Aug 1995 |
| 4270 | Oxford Oil Inc | Cleveland, OK 74020 | Oil & Gas Operator | Feb 1997 |
| 4271 | Oxley Energy LLC | Houston, TX 77042 | Gas Operator | Mar 2025 |
| 4272 | Oxley John C | Tulsa, OK 74103 | Oil & Gas Operator | Sep 1996 |
| 4273 | Oxley Petroleum | Tulsa, OK 74119-3609 | Oil & Gas Operator | Jan 2020 |
| 4274 | Oxley Petroleum Co | Oklahoma City, OK 73118-1044 | Oil & Gas Operator | Sep 2017 |
| 4275 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Jun 2025 |
| 4276 | Ozark Oil Corporation | Springfield, MO 65804 | Oil & Gas Operator | Oct 1992 |
| 4277 | P & C Oil Company | Leona, TX 75850 | Oil & Gas Operator | Apr 2025 |
| 4278 | P & H Construction Inc | Wewoka, OK 74884 | Oil & Gas Operator | Jun 2024 |
| 4279 | P & H Oil & Gas Inc | Stroud, OK 74079 | Oil & Gas Operator | Apr 2025 |
| 4280 | P & M Drilling Company Inc | Depew, OK 74028 | Oil & Gas Operator | Dec 2004 |
| 4281 | P & M Petroleum Management | Denver, CO BAD ADDR | Oil & Gas Operator | Apr 2010 |
| 4282 | P & P Producing Inc | Midland, TX 79702 | Oil & Gas Operator | Feb 2015 |
| 4283 | P A Energy Inc | Calvin, OK 74531-0248 | Oil & Gas Operator | Apr 2020 |
| 4284 | P F Beeler LLC | Norman, OK 73072-7522 | Oil & Gas Operator | Apr 2025 |
| 4285 | P I C Inc | Ponca City, OK 74602 | Oil & Gas Operator | Jan 2013 |
| 4286 | P K & L Oil Properties | Shawnee, OK 74802-0931 | Oil & Gas Operator | Mar 2001 |
| 4287 | P O & G Panhandle LP | Houston, TX 77057 | Oil & Gas Operator | Mar 2025 |
| 4288 | P T Oil Co Inc | Walters, OK 73572-9505 | Oil Operator | Nov 2014 |
| 4289 | P-2 Exploraton Co Inc | Pampa, TX 79065-2920 | Oil & Gas Operator | Jun 1996 |
| 4290 | P.O.&G. Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Jun 2025 |
| 4291 | Pablo Energy II, LLC | Amarillo, TX 79105 | Oil & Gas Operator | Mar 2025 |
| 4292 | Pace Exploration LLC | Tulsa, OK 74133 | Oil & Gas Operator | Feb 2025 |
| 4293 | Pace Petroleum Company | Dallas, TX 75206 | Oil & Gas Operator | Jun 2025 |
| 4294 | Pacific Enterprise Oil Co USA | Los Angeles, CA 90071-2005 | Oil & Gas Operator | Aug 2012 |
| 4295 | Pacific Enterprises Royalty Co | Oklahoma City, OK 73101 | Oil & Gas Operator | Feb 2002 |
| 4296 | Pactola Development Co | Tulsa, OK 74159 | Oil & Gas Operator | Sep 2004 |
| 4297 | Page Petroleum Inc | Calgary, AB T2P3M-3000 | Oil & Gas Operator | Nov 1998 |
| 4298 | Painter & McPhail | Bartlesville, OK 74006 | Oil Operator | Sep 1996 |
| 4299 | Pak Energy LLC | Calgary, AB T3A-5E8 | Oil Operator | Sep 2022 |
| 4300 | Pal Energy LLC | Guymon, OK 73942-1950 | Gas Operator | Aug 2009 |