| 4001 | NM&O Operating Company | Tulsa, OK 74103 | Oil & Gas Operator | Feb 2025 |
| 4002 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | May 2026 |
| 4003 | Noble Energy Production Inc | Houston, TX 77067 | Oil & Gas Operator | May 2026 |
| 4004 | Noble Operating Company Inc | Garden City, KS 67846 | Oil & Gas Operator | Sep 2014 |
| 4005 | Noble Operating, LLC | Flower Mound, TX 75028 | Oil & Gas Operator | Sep 2013 |
| 4006 | Noble Resources Inc | Mannford, OK 74044 | Oil & Gas Operator | Jan 2026 |
| 4007 | Noco Investment Company Inc | Tulsa, OK 74159-0470 | Oil & Gas Operator | Mar 2005 |
| 4008 | Nogp Operating Company Inc | Tomball, TX 77377 | Oil & Gas Operator | Jan 2026 |
| 4009 | Nondorf Oil & Gas Inc | Oklahoma City, OK 73154 | Oil & Gas Operator | Feb 2008 |
| 4010 | Nooner Cynthia | Ratliff City, OK 73481 | Oil Operator | Oct 2025 |
| 4011 | Nordan Oil & Gas Corporation | Abilene, TX 79604 | Oil & Gas Operator | Feb 2018 |
| 4012 | Nordstrand Engineering Inc | Houston, TX 77019 | Oil & Gas Operator | May 2026 |
| 4013 | Norman Brothers Tank Truck Inc | Pauls Valley, OK 73075 | Oil & Gas Operator | May 2020 |
| 4014 | Norman Kenneth W | Sasakwa, OK 74867-0086 | Oil Operator | Oct 2017 |
| 4015 | Norman Oil Corporation | Abilene, TX 79608 | Oil & Gas Operator | Mar 2000 |
| 4016 | Norman Production Company | Chandler, OK 74834-8538 | Oil & Gas Operator | May 2015 |
| 4017 | Nortex Gas & Oil Co | Tulsa, OK 74135 | Oil & Gas Operator | Sep 1993 |
| 4018 | North American Energy Inc | Duncan, OK 73533-9604 | Oil & Gas Operator | Nov 2000 |
| 4019 | North American Operating, LLC | Ardmore, OK 73401 | Oil & Gas Operator | Feb 2026 |
| 4020 | North American Royalties, Inc. | Chattanooga, TN 37408 | Oil & Gas Operator | Oct 2001 |
| 4021 | North Bound Exploration Co | Pauls Valley, OK 73075-0863 | Oil & Gas Operator | Jan 2018 |
| 4022 | North Canadian Production LLC | Okemah, OK 74859 | Oil & Gas Operator | Jan 2026 |
| 4023 | North Lake Resources LLC | Oklahoma City, OK 73132 | Oil & Gas Operator | Feb 2026 |
| 4024 | North Star Exploration Company | Oklahoma City, OK 73116 | Oil & Gas Operator | Jan 2026 |
| 4025 | North Star Petroleum Corp. | San Antonio, TX 78209 | Oil & Gas Operator | Oct 1993 |
| 4026 | Northam Oil Company Inc | Ada, OK 74820-3334 | Oil & Gas Operator | Jan 2026 |
| 4027 | Northbrook Oil & Gas Co LLC | Norman, OK 73072 | Oil & Gas Operator | Nov 2014 |
| 4028 | Northbrook Oil & Gas Company | Norman, OK 73070-4916 | Oil & Gas Operator | Jun 2016 |
| 4029 | Northcote Cleveland LLC | Borger, TX 79008 | Oil & Gas Operator | Nov 2025 |
| 4030 | Northeast Shelf Energy, L.L.C. | | Oil & Gas Operator | Jun 2017 |
| 4031 | Northern Pump Company | Denver, CO 80202-3130 | Oil & Gas Operator | Feb 2006 |
| 4032 | Northport Production Company | Oklahoma City, OK 73113 | Oil & Gas Operator | Feb 2026 |
| 4033 | Northwest Disposal Corporation | Laverne, OK 73848-0504 | Oil & Gas Operator | Jul 2014 |
| 4034 | Northwest Exploration Co | Salt Lake City, UT 84108-0900 | Oil & Gas Operator | Sep 1991 |
| 4035 | Northwest Oil Company | Dallas, TX 75204 | Oil & Gas Operator | Jun 2014 |
| 4036 | Northwind Development Company | | Oil Operator | Oct 1995 |
| 4037 | Northwind Oil Company | Tulsa, OK 74137 | Oil & Gas Operator | May 1998 |
| 4038 | Nossaman E Oil Inc | Del City, OK 73155-5449 | Oil Operator | Oct 2002 |
| 4039 | Notting Hill Energy LLC | Fort Worth, TX 76101 | Oil & Gas Operator | May 2026 |
| 4040 | Nova Energy Corporation | Denver, CO 80201 | Oil & Gas Operator | Jun 2003 |
| 4041 | Novo II Operating, LLC | Oklahoma City, OK 73116 | Gas Operator | Feb 2026 |
| 4042 | Novy Oil & Gas, Inc. | Goddard, KS 67052 | Oil & Gas Operator | Mar 2026 |
| 4043 | Nowata Gas Company | Tulsa, OK 74136 | Oil & Gas Operator | Sep 1997 |
| 4044 | Nowata Petroleum Operating Co | Nowata, OK 74048-9617 | Oil Operator | Aug 2014 |
| 4045 | NRG Oil LLC | Stratford, OK 74872-9732 | Oil Operator | Feb 2012 |
| 4046 | NS Oil LLC | Minneapolis, MN 55410 | Oil Operator | Jan 2026 |
| 4047 | NTR Energy LLC (Osage Cty Only) | | Oil & Gas Operator | Apr 2020 |
| 4048 | Nub'S Well Servicing Inc | Ratliff City, OK 73481 | Oil & Gas Operator | Feb 2026 |
| 4049 | Nutt Jerrie | Duncan, OK 73534-0698 | Oil & Gas Operator | Nov 2016 |
| 4050 | NV O&G Investments LLC /Osage Only | | Oil Operator | Sep 2022 |
| 4051 | NWM Operating Inc | Okeene, OK 73763 | Oil & Gas Operator | Feb 2026 |
| 4052 | NWM Properties LLC | Tulsa, OK 74131-4426 | Oil Operator | Feb 2026 |
| 4053 | Nyc Resources LTD | Tulsa, OK 74133-5700 | Oil & Gas Operator | Sep 2014 |
| 4054 | Nye Oil Company | Oklahoma City, OK 73118-1245 | Oil & Gas Operator | Jun 2004 |
| 4055 | Nytex Energy LLC | Edmond, OK 73083-5946 | Oil & Gas Operator | Sep 2015 |
| 4056 | Nytex, L.L.C. | Edmond, OK 73083 | Oil & Gas Operator | Feb 2006 |
| 4057 | O G & E | Oklahoma City, OK 73124 | Oil & Gas Operator | Feb 2014 |
| 4058 | O K Swabbing Inc | Hennessey, OK 73742 | Oil & Gas Operator | Feb 2026 |
| 4059 | O'Blue Corp. | Kerrville, TX 78028 | Oil & Gas Operator | Mar 1998 |
| 4060 | O'Brien Energy Resources Corp | Portsmouth, NH 03801 | Oil & Gas Operator | May 2026 |
| 4061 | O'Brien Oil Corporation | Guthrie, OK 73044-3154 | Oil & Gas Operator | Jan 2026 |
| 4062 | O'Brien Oil LLC | Guthrie, OK 73044-3154 | Oil & Gas Operator | Apr 2020 |
| 4063 | O'Brien Resources LLC | Shreveport, LA 71136 | Oil Operator | Nov 2017 |
| 4064 | O'Donnell Bill C | Tulsa, OK 74135-4241 | Oil & Gas Operator | Oct 2014 |
| 4065 | O'Hern Morris D | Mounds, OK 74047-5163 | Oil & Gas Operator | Sep 2016 |
| 4066 | O'Neal Oil & Gas Co | Fort Worth, TX 76107-1479 | Oil & Gas Operator | Feb 2026 |
| 4067 | O'Neal Oil Company | Nocona, TX 76255 | Oil & Gas Operator | May 2026 |
| 4068 | O'Neal, Lindell | Nocona, TX 76255 | Oil & Gas Operator | Jan 2026 |
| 4069 | O'Neill Properties, LTD. | Midland, TX 79702 | Oil & Gas Operator | May 2026 |
| 4070 | O.G.P. Operating, Inc. | Dallas, TX 75231 | Oil & Gas Operator | May 2026 |
| 4071 | Oak Hill Petroleum Corporation | Oklahoma City, OK 73116-5627 | Oil & Gas Operator | Jan 2026 |
| 4072 | Oak Hills Drilling & Oper., LLC | Holdenville, OK 74848 | Oil & Gas Operator | May 2013 |
| 4073 | Oak Hills Energy Inc | Holdenville, OK 74848-0470 | Oil & Gas Operator | Sep 2014 |
| 4074 | Oak Resources Inc | Tulsa, OK 74153 | Oil & Gas Operator | Aug 2013 |
| 4075 | Oak Tree Natural Res LLC | Oklahoma City, OK 73120-5065 | Oil & Gas Operator | Mar 2015 |
| 4076 | Oak Valley SWD LLC | Enid, OK 73703-4637 | Oil Operator | Aug 2022 |
| 4077 | Oakland Petroleum Oper Co., Inc. | Kilgore, TX 75663 | Oil & Gas Operator | May 2026 |
| 4078 | Oakwood Resources Inc | Dallas, TX 75374 | Oil & Gas Operator | May 1998 |
| 4079 | Oasis Energy Resources LLC | Norman, OK 73072-9668 | Oil & Gas Operator | Jun 2025 |
| 4080 | Obele Oil Corporation | Sedona, AZ 86336-5745 | Oil & Gas Operator | May 2017 |
| 4081 | Obele Operating Company LLC | Sedona, AZ 86336-5745 | Oil & Gas Operator | Oct 2025 |
| 4082 | Oberlander Leslie A Jake | Covington, OK 73730 | Oil Operator | Jun 2007 |
| 4083 | Ochiltree Oil Company | Edmond, OK 73034 | Oil & Gas Operator | Apr 2020 |
| 4084 | Octagon Resources LLC | Norman, OK 73071-1295 | Oil & Gas Operator | May 2015 |
| 4085 | Odell Larry | Oologah, OK 74053 | Oil Operator | Apr 2011 |
| 4086 | Odessa Oil Investment Co., Inc. | Odessa, TX 79762 | Oil & Gas Operator | Nov 2016 |
| 4087 | Odum Ronald L | Ponca City, OK 74601 | Oil Operator | Jan 2026 |
| 4088 | Oex-1 LLC | Tulsa, OK 74105-5153 | Oil & Gas Operator | Mar 2024 |
| 4089 | Oexco, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2015 |
| 4090 | Offield Lease Operations LLC | Wilson, OK 73463 | Oil & Gas Operator | May 2023 |
| 4091 | Ofs-Tulsa Corporation | Fort Worth, TX 76102 | Oil & Gas Operator | Feb 1997 |
| 4092 | Oil & Gas Exploration Inc | Cleveland, OK 74020 | Oil & Gas Operator | Aug 2013 |
| 4093 | Oil Capital Operating, LLC | Tulsa, OK 74103 | Oil & Gas Operator | May 2026 |
| 4094 | Oil Center Operating Inc | Fort Worth, TX 76102-5108 | Oil & Gas Operator | Apr 2014 |
| 4095 | Oil Creek Production Company | Prague, OK 74864-0667 | Oil & Gas Operator | Dec 2025 |
| 4096 | Oil Exploration Of America Inc | Sisseton, SD 57262-9503 | Oil & Gas Operator | Jun 2001 |
| 4097 | Oil Investors Inc | Crescent, OK 73028 | Oil & Gas Operator | Feb 2026 |
| 4098 | Oil Lift Inc | Metairie, LA 70002 | Oil & Gas Operator | Apr 2020 |
| 4099 | Oil Operations Inc | | Oil & Gas Operator | Apr 2011 |
| 4100 | Oil Patch Energy LLC | Broken Arrow, OK 74014 | Oil & Gas Operator | Nov 2025 |