| Name | Company Number | Date Appointed | Rating |
|---|---|---|---|
| COGAP LIMITED | 06454206 | 14/12/2007 | Dissolved |
| NATIONAL ROAD OPERATORS LIMITED | 02969113 | 12/09/2005 | Dissolved |
| PERSIMMON PUBLIC LIMITED COMPANY | 01818486 | 04/01/2021 | Silver |
| YORKSHIRE WATER SERVICES LIMITED | 02366682 | 01/09/2017 | Silver |
| Name | Company Number | Date Appointed | Date Resigned | Rating |
|---|---|---|---|---|
| BMT GROUP LIMITED | 01887373 | 21/10/2019 | 18/04/2023 | Bronze |
| C. G. NOMINEES LIMITED | 01445212 | 12/09/2005 | 25/05/2011 | Dissolved |
| COGAP (MIDDLE EAST) LIMITED | 06454224 | 14/12/2007 | 07/05/2019 | Amber |
| COSTAIN ALCAIDESA LIMITED | 02042076 | 12/09/2005 | 07/05/2019 | Bronze |
| COSTAIN BUILDING & CIVIL ENGINEERING LIMITED | 01054232 | 12/09/2005 | 07/05/2019 | Gold |
| COSTAIN CIVIL ENGINEERING LIMITED | 02757907 | 22/12/2005 | 07/05/2019 | Amber |
| COSTAIN CONSTRUCTION LIMITED | 00563270 | 12/09/2005 | 07/05/2019 | Not Trading |
| COSTAIN ENGINEERING & CONSTRUCTION (OVERSEAS) LIMITED | 02440830 | 12/09/2005 | 07/05/2019 | Gold |
| COSTAIN ENGINEERING & CONSTRUCTION LIMITED | 02440829 | 12/09/2005 | 07/05/2019 | Gold |
| COSTAIN GROUP PLC | 01393773 | 12/09/2005 | 07/05/2019 | Gold |
| COSTAIN INTEGRATED TECHNOLOGY SOLUTIONS LIMITED | 01439838 | 05/07/2016 | 07/05/2019 | Gold |
| COSTAIN INTERNATIONAL LIMITED | 00563275 | 12/09/2005 | 07/05/2019 | Amber |
| COSTAIN LIMITED | 00610201 | 12/09/2005 | 07/05/2019 | Silver |
| COSTAIN OIL, GAS & PROCESS (OVERSEAS) LIMITED | 00583789 | 12/09/2005 | 07/05/2019 | Not Trading |
| COSTAIN OIL, GAS & PROCESS LIMITED | 00786418 | 12/09/2005 | 07/05/2019 | One Red Flag |
| COUNTY & DISTRICT PROPERTIES LIMITED | 00675355 | 12/09/2005 | 07/05/2019 | Silver |
| RENOWN INVESTMENTS (HOLDINGS) LIMITED | 00683698 | 12/09/2005 | 07/05/2019 | Gold |
| RICHARD COSTAIN LIMITED | 00274453 | 12/09/2005 | 07/05/2019 | Bronze |
| SCOTTISH WATER BUSINESS STREAM HOLDINGS LIMITED | SC332622 | 25/03/2014 | 31/03/2017 | Gold |
| SCOTTISH WATER HORIZONS HOLDINGS LIMITED | SC334620 | 30/11/2011 | 31/03/2017 | Gold |
| WESTMINSTER PLANT CO. LIMITED | 00552140 | 12/09/2005 | 07/05/2019 | Not Trading |