| 201 | Mack Energy Co. | Duncan, OK 73534 | Oil & Gas Operator | Jan 2025 |
| 202 | Manursing Island Prod. Corp. | | Oil & Gas Operator | Sep 2002 |
| 203 | Mapco Oil & Gas Company | Tulsa, OK 74101-2115 | Oil & Gas Operator | Jan 1985 |
| 204 | Maple Gulf Coast Props. Corp. | | Oil & Gas Operator | Jun 1989 |
| 205 | Marine Cont. & Supply Inc. | | Oil & Gas Operator | Nov 1985 |
| 206 | Marline Petroleum Corporation | | Oil & Gas Operator | Dec 1985 |
| 207 | Marquee Corporation | Houston, TX 77024 | Oil & Gas Operator | Mar 2025 |
| 208 | Marshall Exploration, Inc. | | Oil & Gas Operator | Jun 1992 |
| 209 | Martin Exploration Co. | | Oil & Gas Operator | Apr 1986 |
| 210 | May Oil & Gas, L.L.C. | | Oil & Gas Operator | Dec 2013 |
| 211 | May Petroleum, Inc. | Dallas, TX 75231 | Oil & Gas Operator | Nov 1998 |
| 212 | McCord Exploration Co. | | Oil & Gas Operator | Dec 1990 |
| 213 | McCormick Operating Company | | Oil & Gas Operator | Mar 1984 |
| 214 | McCormick-Bintliff | | Oil & Gas Operator | Feb 1984 |
| 215 | McGowan Working Partners | Jackson, MS 39296 | Oil & Gas Operator | Dec 2000 |
| 216 | McGowan Working Partners, Inc. | Jackson, MS 39296 | Oil & Gas Operator | Mar 2025 |
| 217 | MCZ, Inc. | Houston, TX 77026 | Oil & Gas Operator | Sep 1990 |
| 218 | Medallion Production Company | Tulsa, OK 74103 | Oil & Gas Operator | May 1997 |
| 219 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Mar 2025 |
| 220 | Mertz Energy LLC | Houston, TX 77098 | Oil & Gas Operator | Jan 2025 |
| 221 | Meyers-Lasher, Inc. | | Oil & Gas Operator | Mar 1999 |
| 222 | Mideast Gas Systems, Inc. | Midland, TX 79702 | Oil & Gas Operator | Dec 2005 |
| 223 | Midstates Oil Company | Oklahoma City, OK 73112 | Oil & Gas Operator | Nov 2000 |
| 224 | Midstates Petroleum Company LLC | Tulsa, OK 74103 | Oil & Gas Operator | May 2018 |
| 225 | Midstates Petroleum Corp. | | Oil & Gas Operator | Dec 2008 |
| 226 | Milagro Exploration, LLC | Houston, TX 77010 | Oil & Gas Operator | Aug 2018 |
| 227 | Moco Operating Company | | Oil & Gas Operator | Mar 2002 |
| 228 | Mole Operating Co., Inc. | | Oil & Gas Operator | Oct 1983 |
| 229 | Monexco, Inc. | | Oil Operator | Dec 2003 |
| 230 | Moore McCormack Energy, Inc. | | Oil & Gas Operator | Jul 1988 |
| 231 | Murphy Exploration & Prod. Co. | Houston, TX 77094 | Oil & Gas Operator | Jun 2011 |
| 232 | Murphy Oil USA Inc | New Orleans, LA 70161 | Oil & Gas Operator | Jan 1993 |
| 233 | Mustang Energy Inc. | Porter, TX 77365 | Oil & Gas Operator | Mar 2008 |
| 234 | National Offshore LP | Oklahoma City, OK 73154 | Oil & Gas Operator | Mar 2008 |
| 235 | Neg Operating LLC | Oklahoma City, OK 73101 | Oil & Gas Operator | Nov 2024 |
| 236 | North Central Oil Corp | Houston, TX 77252 | Oil & Gas Operator | Dec 2005 |
| 237 | O'Sullivan & Scully, Inc. | | Oil & Gas Operator | Oct 1994 |
| 238 | O'Sullivan Oil & Gas Co., Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2000 |
| 239 | Ocean Energy, Inc. | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 240 | Orion Oil & Gas, LLC | Houston, TX 77042 | Oil & Gas Operator | Oct 2007 |
| 241 | Orx Resources, L.L.C. | Houston, TX 77067 | Oil & Gas Operator | Mar 2025 |
| 242 | Osman Global Services LLC | | Oil & Gas Operator | Jan 2025 |
| 243 | Output Acquisition Corp. | | Oil & Gas Operator | Jul 2010 |
| 244 | P. B. Operating Company | | Oil & Gas Operator | Feb 1978 |
| 245 | Panaco, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Oct 2024 |
| 246 | Paragon Resources, Inc | | Oil & Gas Operator | Nov 1991 |
| 247 | Penton And Penton | | Oil & Gas Operator | Jan 1983 |
| 248 | Perdido Energy Louisiana, LLC | | Oil & Gas Operator | Dec 2024 |
| 249 | Petro-Guard Company, Inc. | Houston, TX 77057 | Oil & Gas Operator | Nov 2014 |
| 250 | Petro-Guard Production,L.L.C. | Houston, TX 77063 | Oil & Gas Operator | Dec 2024 |
| 251 | Petro-Lewis Corp. | | Oil & Gas Operator | Feb 1994 |
| 252 | Petrohawk Operating Company | Houston, TX 77056 | Oil & Gas Operator | Oct 2021 |
| 253 | Petroleum Corporation Of Texas | Breckenridge, TX 76024 | Oil & Gas Operator | May 2002 |
| 254 | Petroleum Futures-Chapman Oil | | Oil & Gas Operator | Jul 1981 |
| 255 | Petromark Resources Company | Tulsa, OK 74136 | Oil & Gas Operator | Sep 1993 |
| 256 | Phillip A Guzzino | | Oil Operator | Jan 2000 |
| 257 | Pickens Company, Inc., The | Dallas, TX 75225 | Oil & Gas Operator | Jul 2024 |
| 258 | Pie La Operating, LLC | | Oil & Gas Operator | Jan 2025 |
| 259 | Pierce Production Company | Eunice, NM 88231 | Oil & Gas Operator | Oct 2012 |
| 260 | Pilot Resources, Inc. | | Oil & Gas Operator | May 2013 |
| 261 | Pine Island Operating, L.L.C. | Graham, TX 76450 | Oil & Gas Operator | Mar 2025 |
| 262 | Pintail Oil & Gas, LLC | Midland, TX 79702 | Oil & Gas Operator | Dec 2019 |
| 263 | Pittencrieff (Gulf Coast), Inc. | Abilene, TX 79608 | Oil & Gas Operator | Sep 1998 |
| 264 | Pittencrieff America Inc | Abilene, TX 79608 | Oil & Gas Operator | Feb 2003 |
| 265 | Plains Resources Inc. | Houston, TX 77002 | Oil & Gas Operator | Jul 2008 |
| 266 | Pmo | Garland, TX 75040 | Oil & Gas Operator | Feb 2018 |
| 267 | Prairie Producing Company | | Oil & Gas Operator | Dec 1992 |
| 268 | Prime Operating Company | Houston, TX 77024 | Oil & Gas Operator | Mar 2025 |
| 269 | Prudential Oil & Gas, Inc. | | Oil & Gas Operator | Jul 1987 |
| 270 | Pruet Production Co. | Jackson, MS 39201 | Oil & Gas Operator | Dec 2024 |
| 271 | Rebel Drilling Co. Inc. | | Oil & Gas Operator | Oct 1995 |
| 272 | Riceland Petroleum Company | | Oil & Gas Operator | Nov 2024 |
| 273 | Ridgeway Exco, Inc. | San Antonio, TX 78279 | Oil & Gas Operator | Mar 1996 |
| 274 | Rio Grande Drilling Company | San Antonio, TX 78212 | Oil & Gas Operator | Dec 1999 |
| 275 | Ripco | | Oil & Gas Operator | Jul 1986 |
| 276 | Riseden, LTD | | Oil & Gas Operator | Nov 1989 |
| 277 | Rme Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Nov 2016 |
| 278 | S & S Operating Company, Inc. | Winnie, TX 77665 | Oil & Gas Operator | Mar 2025 |
| 279 | S2 Energy Operating LLC | | Oil & Gas Operator | May 2023 |
| 280 | Sandpoint Energy Partners LLC | | Oil Operator | Jan 2025 |
| 281 | Sandridge Exploration And Production LLC | Oklahoma City, OK 73104 | Oil & Gas Operator | Mar 2025 |
| 282 | Santa Fe Energy Company | Midland, TX 79701 | Oil & Gas Operator | Dec 2015 |
| 283 | Santa Fe Energy Operg Parts LP | | Oil & Gas Operator | Nov 1993 |
| 284 | Schmid Properties Inc | Hico, TX 76457 | Oil & Gas Operator | Mar 2025 |
| 285 | Seaboard Pipe & Equip. Co. | | Oil & Gas Operator | May 1977 |
| 286 | Secondary Recovery, Inc. | | Oil & Gas Operator | Dec 1991 |
| 287 | Shell Oil Company | Houston, TX 77210 | Oil & Gas Operator | Apr 2015 |
| 288 | Silver Oak Energy, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2016 |
| 289 | Skelly Oil Co | | Oil & Gas Operator | Mar 2005 |
| 290 | Smith Operating And MGMT Co. | Shreveport, LA 71161 | Oil & Gas Operator | Jun 2023 |
| 291 | Smith Production Co. | Wichita Falls, TX 76308 | Oil & Gas Operator | Mar 2025 |
| 292 | Sohio Petroleum Co. | Casper, WY 82602 | Oil & Gas Operator | Apr 1986 |
| 293 | Sonat Exploration Co. | Houston, TX 77251 | Oil & Gas Operator | Dec 2021 |
| 294 | Sonoran Energy Inc. | Addison, TX 75001 | Oil & Gas Operator | Mar 2025 |
| 295 | Sotrana-Texas Corp. | | Oil & Gas Operator | Oct 1984 |
| 296 | Sound Resources Corporation | | Oil & Gas Operator | Dec 2003 |
| 297 | Source Petroleum Inc. | San Antonio, TX 78265 | Oil & Gas Operator | Mar 2025 |
| 298 | South La. Production Co., Inc. | | Oil & Gas Operator | Jun 1982 |
| 299 | Southco Oil And Gas Inc. | | Oil & Gas Operator | Nov 2000 |
| 300 | Southern Wells, Inc. | | Oil Operator | Sep 2002 |