| Name | Company Number | Date Appointed | Rating |
|---|---|---|---|
| DWR CYMRU CUSTOMER SERVICES LIMITED | 08114592 | 09/07/2012 | Dissolved |
| S4C DIGITAL MEDIA LIMITED | 03418710 | 01/04/2021 | Gold |
| S4C MASNACHOL CYF | 03418713 | 01/04/2021 | Silver |
| S4C PTG CYFYNGEDIG | 11838942 | 01/04/2021 | Gold |
| S4C RHYNGWLADOL CYF | 03542938 | 01/04/2021 | Amber |
| S4C2 CYF. | 03725740 | 01/04/2021 | Gold |
| WELSH WATER UTILITIES FINANCE PLC | 02869784 | 11/05/2001 | Dissolved |
| XOSERVE LIMITED | 05046877 | 01/11/2020 | Silver |
| Name | Company Number | Date Appointed | Date Resigned | Rating |
|---|---|---|---|---|
| CAMBRIAN UTILITIES LIMITED | 10082803 | 24/03/2016 | 19/11/2019 | One Red Flag |
| DWR CYMRU (FINANCING) LIMITED | FC023222 | 11/05/2001 | 15/05/2020 | Dissolved |
| DWR CYMRU (FINANCING) UK PLC | 11949988 | 16/04/2019 | 15/05/2020 | Silver |
| DWR CYMRU (HOLDINGS) LIMITED | 03954867 | 11/05/2001 | 15/05/2020 | Silver |
| DWR CYMRU CYFYNGEDIG | 02366777 | 07/02/1996 | 03/11/2000 | Amber |
| Dwr Cymru (Properties) Ltd | 03310610 | 12/03/1997 | 03/11/2000 | Dissolved |
| Electricity Association Ltd | 02367010 | 15/08/1999 | 01/12/2000 | Dissolved |
| GLAS CYMRU (SECURITIES) CYFYNGEDIG | 04129132 | 01/02/2001 | 15/05/2020 | Amber |
| GLAS CYMRU ANGHYFYNGEDIG | 03975719 | 13/04/2000 | 15/05/2020 | Bronze |
| GLAS CYMRU HOLDINGS CYFYNGEDIG | 09917809 | 15/12/2015 | 15/05/2020 | Bronze |
| Hyder Utilities (Operations) Ltd | 03405264 | 19/05/1998 | 03/11/2000 | Dissolved |
| INSTITUTE OF WELSH AFFAIRS | 02151006 | 05/07/2005 | 13/10/2009 | Gold |
| Infralec Investments Ltd | 02624639 | 04/05/1999 | 03/11/2000 | Dissolved |
| WATER UK | 03539600 | 01/06/2008 | 31/03/2020 | Bronze |
| WELSH WATER HOLDINGS LIMITED | 10079953 | 23/03/2016 | 19/11/2019 | One Red Flag |
| WELSH WATER INFRASTRUCTURE LIMITED | 10082776 | 24/03/2016 | 19/11/2019 | One Red Flag |
| WELSH WATER ORGANIC ENERGY (CARDIFF) LTD | 08356859 | 19/12/2017 | 19/11/2019 | Amber |
| WELSH WATER ORGANIC ENERGY LTD | 08356949 | 19/12/2017 | 19/11/2019 | Bronze |
| WELSH WATER ORGANIC WASTE LIMITED | 11468450 | 17/07/2018 | 19/11/2019 | Silver |
| WELSH WATER UTILITIES FINANCE PLC | 02869784 | 29/01/1997 | 03/11/2000 | Dissolved |