| 21201 | Ojt, LLC | Richmond, TX 77469 | Oil Operator | May 2025 |
| 21202 | Ok Arena Operating Company | Oklahoma City, OK 73101 | Oil & Gas Operator | May 2025 |
| 21203 | Ok Oil Company, Inc. | Bivins, TX 75555 | Oil & Gas Operator | Feb 2013 |
| 21204 | Ok Operating Co | Midland, TX 79702 | Oil & Gas Operator | Aug 1999 |
| 21205 | Ok Production Services Inc | Broken Arrow, OK 74014 | Oil & Gas Operator | Feb 2025 |
| 21206 | Ok-La-Tex Production, Inc. | | Oil & Gas Operator | Jan 1982 |
| 21207 | Okc Energy Corporation | Oklahoma City, OK 73120-3119 | Oil & Gas Operator | Nov 2014 |
| 21208 | Okemah Production Inc | | Oil Operator | Dec 2005 |
| 21209 | Okie Crude Company | Tulsa, OK 74103 | Oil & Gas Operator | Feb 2025 |
| 21210 | Okie Oil Inc | Sapulpa, OK 74067-0290 | Oil & Gas Operator | Mar 2011 |
| 21211 | Okie Operating Company, LTD. | Tulsa, OK 74103 | Oil & Gas Operator | May 2025 |
| 21212 | Okkatahula, Inc. | | Oil Operator | Nov 1978 |
| 21213 | Okla Sub-Surface Pump & Supply Co | Seminole, OK 74804 | Oil & Gas Operator | Sep 2024 |
| 21214 | Okla. Magic Circle Energy Corp. | Shawnee, OK 74801 | Oil & Gas Operator | Jul 2004 |
| 21215 | Oklahoma Arrowhead Energy, Inc. | Nichols Hill, OK 73116 | Oil & Gas Operator | Sep 1996 |
| 21216 | Oklahoma Basic Economy Corp | Houston, TX 77002-6003 | Oil & Gas Operator | Apr 2020 |
| 21217 | Oklahoma Cellulose Inc | Cleveland, OK 74020 | Oil Operator | Feb 2025 |
| 21218 | Oklahoma Crude Inc | Broken Arrow, OK 74012 | Oil & Gas Operator | Apr 2024 |
| 21219 | Oklahoma Crude Reclaimers, LLC | | Oil Operator | Mar 2025 |
| 21220 | Oklahoma Ea II, L.L.C. | Oklahoma City, OK 73102 | Oil & Gas Operator | Dec 2004 |
| 21221 | Oklahoma Energy & Exploration, Inc. | Tulsa, OK 74114 | Oil Operator | Jan 1996 |
| 21222 | Oklahoma Energy Acquisitions LP | Houston, TX 77094-1900 | Oil & Gas Operator | Jan 2025 |
| 21223 | Oklahoma Energy Exchange LLC | Duncan, OK 73534-1105 | Oil & Gas Operator | Sep 2012 |
| 21224 | Oklahoma Energy LLC | Skiatook, OK 74070-3998 | Oil Operator | Nov 2024 |
| 21225 | Oklahoma Equipment & Salvage | Oklahoma City, OK 73120-5903 | Oil & Gas Operator | Mar 2015 |
| 21226 | Oklahoma Gas & Oil Corp | | Oil Operator | Oct 2018 |
| 21227 | Oklahoma Liquid Resources Inc | Collinsville, OK 74021 | Oil & Gas Operator | Feb 2025 |
| 21228 | Oklahoma Marlin Oil Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Feb 2020 |
| 21229 | Oklahoma Natural Resources Inc | Woodward, OK 73801 | Oil & Gas Operator | Sep 1996 |
| 21230 | Oklahoma O & G Royalties Inc | Duncan, OK 73533 | Oil & Gas Operator | Nov 2000 |
| 21231 | Oklahoma Oil & Gas MGMT Inc | Edmond, OK 73083-6786 | Oil & Gas Operator | Feb 2025 |
| 21232 | Oklahoma Oil And Gas Resources LLC | Guthrie, OK 73044-8095 | Oil & Gas Operator | Feb 2025 |
| 21233 | Oklahoma Oil Company | Dallas, TX 75206 | Oil & Gas Operator | Aug 2013 |
| 21234 | Oklahoma Oil Tactics Inc | Edmond, OK 73003-1351 | Oil & Gas Operator | Mar 2015 |
| 21235 | Oklahoma Operating Company | Midland, TX 79708 | Oil & Gas Operator | May 2025 |
| 21236 | Oklahoma Operating, LLC | Holliday, TX 76366 | Oil Operator | Nov 2003 |
| 21237 | Oklahoma Petroleum MGMT Corp | Tulsa, OK 74119 | Oil & Gas Operator | Jun 1993 |
| 21238 | Oklahoma Prime Energy LLC | Ardmore, OK 73401 | Oil Operator | May 2020 |
| 21239 | Oklahoma Prod & Exp Co | Broken Arrow, OK 74012 | Oil & Gas Operator | May 2013 |
| 21240 | Oklahoma RB Operating Company | Midland, TX 79701 | Oil & Gas Operator | Jan 1998 |
| 21241 | Oklahoma Rig & Salvage, Inc. | Oklahoma City, OK 73114 | Oil & Gas Operator | Mar 2015 |
| 21242 | Oklahoma Sterling Oil & Gas Corp | Tulsa, OK 74170 | Oil & Gas Operator | Jun 1997 |
| 21243 | Oklahoma SWD Systems Inc | Odessa, TX 79762-8132 | Oil & Gas Operator | Feb 2025 |
| 21244 | Oklahoma Tank Service Inc | Oklahoma City, OK 73143 | Oil Operator | Aug 1997 |
| 21245 | Okland Oil Company | Oklahoma City, OK 73102-9022 | Oil & Gas Operator | Mar 2025 |
| 21246 | Oklaoleum Oil And Gas Inc | Bristow, OK 74010-0057 | Oil Operator | Jan 2016 |
| 21247 | Oklatex Energy, Inc. | Beaumont, TX 77702 | Oil Operator | May 2025 |
| 21248 | Okmar Oil Compan | | Oil & Gas Operator | Feb 1995 |
| 21249 | Okmar Oil Company | Marietta, OH 45750 | Oil & Gas Operator | Jun 2005 |
| 21250 | Okreek Oil Company | Weatherford, TX 76086 | Oil & Gas Operator | May 2025 |
| 21251 | Okt Petroleum Company Inc | Oklahoma City, OK 73118-7425 | Oil & Gas Operator | Oct 2013 |
| 21252 | Okt Resources, LLC | Edmond, OK 73013 | Oil & Gas Operator | May 2025 |
| 21253 | Oktex Operating LLC | Edmond, OK 73013-1961 | Oil & Gas Operator | May 2020 |
| 21254 | Oky Investments, Inc. | Edmond, OK 73013 | Oil & Gas Operator | Sep 2021 |
| 21255 | Ol' Boys Operations LLC | Pampa, TX 79065 | Oil & Gas Operator | May 2025 |
| 21256 | Ol' Oily LLC | | Oil Operator | Jan 2025 |
| 21257 | Old Acres Farm, Inc. | Perry, NY 14530 | Gas Operator | Dec 2023 |
| 21258 | Old Cedron, L.L.C. | Lubbock, TX 79410 | Oil & Gas Operator | May 2004 |
| 21259 | Old Chief Oil, LLC | New Braunfels, TX 78132 | Oil Operator | May 2025 |
| 21260 | Old Dominion Oil Corporation | Oklahoma City, OK 73107 | Oil & Gas Operator | Apr 2009 |
| 21261 | Old Field Associates | | Oil & Gas Operator | Mar 2025 |
| 21262 | Old MTN Gas Co Inc | Pleasantville, PA 16341-0329 | Oil & Gas Operator | Dec 2020 |
| 21263 | Old Pine Energy Corporation | Austin, TX 78755 | Oil Operator | May 2025 |
| 21264 | Old South Oil LLC | Marietta, OH 45750 | Oil & Gas Operator | Dec 2023 |
| 21265 | Old Timers Oil | Saratoga, TX 77585 | Oil & Gas Operator | Nov 2014 |
| 21266 | Old Timers Oil Company, LLC | Saratoga, TX 77585 | Oil Operator | Aug 2022 |
| 21267 | Old Timers Oil No. 2 Incorporated | Saratoga, TX 77585 | Oil Operator | May 2025 |
| 21268 | Old Union Operating Company | Austin, TX 78716 | Oil & Gas Operator | May 2025 |
| 21269 | Olde Chautauqua Farms | Portland, NY 14769 | Gas Operator | Dec 2023 |
| 21270 | Older Than Dirt LLC | Palo Pinto, TX 76484 | Oil & Gas Operator | May 2025 |
| 21271 | Oldfield Acquisition LP | Austin, TX 78733 | Oil & Gas Operator | Sep 1996 |
| 21272 | Oldfield Operating Corporation | | Oil Operator | Dec 2013 |
| 21273 | Olds Oil Company | Casper, WY 82604 | Oil Operator | Jun 1988 |
| 21274 | Ole Chaparral On Possum Kingdom | Wichita Falls, TX 76307 | Oil & Gas Operator | Dec 1997 |
| 21275 | Ole Crow Operating | Wichita Falls, TX 76308 | Oil Operator | Feb 2025 |
| 21276 | Ole Miss Oil & Gas Inc | New Bremen, OH 45689 | Oil & Gas Operator | Dec 1985 |
| 21277 | Ole, Inc. | Graham, TX 76450 | Oil & Gas Operator | Aug 2003 |
| 21278 | Oleksandr Antonyuk | | Oil & Gas Operator | Dec 2018 |
| 21279 | Oleum Energy LLC | Georgetown, TX 78628 | Oil & Gas Operator | Mar 2025 |
| 21280 | Oleum Exploration, LLC | Brodheadsvill, PA 18322 | Oil & Gas Operator | Mar 2023 |
| 21281 | Oleum Incorporat | | Gas Operator | Dec 1990 |
| 21282 | Oleum Incorporated | | Oil & Gas Operator | Mar 1996 |
| 21283 | Oleum Operating Company, L.C. | Longview, TX 75606 | Oil & Gas Operator | Dec 2021 |
| 21284 | Oleum Operating La LLC | | Oil & Gas Operator | Nov 2022 |
| 21285 | Oleum Partners, LLC | Frisco, TX 75034 | Oil & Gas Operator | May 2025 |
| 21286 | Olia Oil & Gas Services LLC | Cedar Park, TX 78630-2049 | Oil & Gas Operator | Aug 2022 |
| 21287 | Oliditt Corporation | | Gas Operator | Mar 2022 |
| 21288 | Oliditt Production Inc. | | Gas Operator | Sep 1998 |
| 21289 | Olifant Energy LLC | Tulsa, OK 74119 | Oil & Gas Operator | Jun 2019 |
| 21290 | Olipdp II, LLC | Lafayette, LA 70503 | Oil & Gas Operator | May 2025 |
| 21291 | Oliphant Gertrud | Holdenville, OK 74848-0849 | Oil Operator | Aug 2013 |
| 21292 | Oliphant Operating Co,LTD,LLC | | Oil Operator | Feb 2025 |
| 21293 | Olive Oil & Gas | Ellensboro, WV 26346 | Oil & Gas Operator | Dec 2021 |
| 21294 | Olive Oil & Gas Inc | Jennings, OK 74052 | Oil & Gas Operator | Nov 2024 |
| 21295 | Oliver Oil & Gas | Midland, TX 79702 | Oil & Gas Operator | May 2025 |
| 21296 | Olmos Partners, Inc. | Boerne, TX 78006 | Oil & Gas Operator | May 2025 |
| 21297 | Olney Oil LLC | Boerne, TX 78006 | Oil Operator | May 2025 |
| 21298 | Olney Properties, Inc. | Wichita Falls, TX 76307 | Oil & Gas Operator | Sep 2003 |
| 21299 | Olsan Brothers, Inc. | Dallas, TX 75251 | Oil & Gas Operator | Apr 1994 |
| 21300 | Olsen Energy Inc. | Boerne, TX 78006 | Oil & Gas Operator | May 2025 |