| Name | Company Number | Date Appointed | Rating |
|---|---|---|---|
| COOK (E&P) LIMITED | 08116495 | 04/02/2013 | Dissolved |
| FIRST OIL EXPLORATION (UK) LIMITED | 01005418 | 13/08/2002 | Dissolved |
| First Oil International North Sea Ltd | 02487444 | 13/08/2002 | Dissolved |
| First Textile Flooring Ltd | SC227803 | 05/01/2005 | Dissolved |
| JERSEY OIL AND GAS PLC | 07503957 | 22/11/2021 | Amber |
| Roots Gas Ltd | SC205750 | 13/08/2002 | Dissolved |
| Name | Company Number | Date Appointed | Date Resigned | Rating |
|---|---|---|---|---|
| FIRST CAPITAL DEVELOPMENTS LIMITED | SC282301 | 27/07/2005 | 23/04/2010 | Dissolved |
| FIRST OIL EXPLORATION (NORTH SEA) LIMITED | SC248243 | 21/06/2007 | 23/04/2010 | Dissolved |
| FIRST OIL EXPRO LIMITED | 01021486 | 13/08/2002 | 23/04/2010 | Dissolved |
| FIRST OIL PLC | SC191745 | 13/08/2002 | 23/04/2010 | Dissolved |
| FIRST OIL ROYALTIES LIMITED | 02772880 | 30/10/2007 | 23/04/2010 | Dissolved |
| FIRST OIL SNS LIMITED | 00986309 | 19/10/2004 | 23/04/2010 | Dissolved |
| FIRST OIL UK HOLDINGS LIMITED | 01282732 | 13/08/2002 | 23/04/2010 | Dissolved |
| FIRST SUBSEA LIMITED | 02894198 | 01/04/2003 | 30/04/2003 | Bronze |
| FIRST TECH LIMITED | SC282302 | 27/07/2005 | 23/04/2010 | Silver |
| FIRST WHISKY LIMITED | SC223370 | 05/01/2005 | 23/04/2010 | Dissolved |
| ITHACA ENERGY (UK) LIMITED | SC272009 | 03/05/2010 | 31/01/2021 | Silver |
| ITHACA OIL AND GAS LIMITED | 01546623 | 08/11/2019 | 31/01/2021 | Amber |
| TANO ENERGY LIMITED | SC197827 | 13/08/2002 | 23/04/2010 | Dissolved |