| Name | Company Number | Date Appointed | Rating |
|---|---|---|---|
| HARTHAM HALL LIMITED | 02058207 | 13/02/2008 | Silver |
| LATTICE GROUP LIMITED | 03900804 | 01/10/2019 | Silver |
| NATIONAL GRID COMMERCIAL HOLDINGS LIMITED | 04042700 | 01/11/2017 | Silver |
| NATIONAL GRID ELECTRICITY GROUP TRUSTEE LIMITED | 08100662 | 01/10/2024 | Not Trading |
| NATIONAL GRID HOLDINGS ONE PLC | 02367004 | 01/07/2020 | Silver |
| NATIONAL GRID TWENTY THREE LIMITED | 06999009 | 01/11/2017 | Dissolved |
| NATIONAL GRID US 6 LLC | FC028513 | 13/07/2020 | Amber |
| Name | Company Number | Date Appointed | Date Resigned | Rating |
|---|---|---|---|---|
| GAST MIDCO LIMITED | 14177081 | 31/01/2023 | 11/03/2024 | Bronze |
| GAST PLEDGECO LIMITED | 14176779 | 31/01/2023 | 11/03/2024 | Gold |
| GAST TOPCO LIMITED | 14176279 | 31/01/2023 | 11/03/2024 | Bronze |
| NATGRID ONE LIMITED | 05521240 | 01/07/2020 | 21/06/2022 | Dissolved |
| NATGRIDTW1 LIMITED | 07579324 | 01/07/2020 | 01/10/2024 | Not Trading |
| NATIONAL GAS METERING LIMITED | 03705992 | 31/01/2023 | 11/03/2024 | Silver |
| NATIONAL GAS TRANSMISSION HOLDINGS LIMITED | 03675375 | 31/01/2023 | 11/03/2024 | Amber |
| NATIONAL GAS TRANSMISSION PLC | 02006000 | 31/01/2023 | 11/03/2024 | Silver |
| NATIONAL GRID (US) HOLDINGS LIMITED | 02630496 | 01/11/2017 | 01/10/2024 | Gold |
| NATIONAL GRID (US) INVESTMENTS 2 LIMITED | 03784528 | 01/07/2020 | 21/06/2022 | Dissolved |
| NATIONAL GRID (US) INVESTMENTS 4 LIMITED | 03867128 | 01/07/2020 | 01/10/2024 | Bronze |
| NATIONAL GRID (US) PARTNER 1 LIMITED | 04314432 | 01/07/2020 | 01/10/2024 | Amber |
| NATIONAL GRID ELECTRICITY GROUP TRUSTEE LIMITED | 08100662 | 01/06/2022 | 01/10/2024 | Not Trading |
| NATIONAL GRID HOLDINGS LIMITED | 03096772 | 01/10/2019 | 01/10/2024 | Silver |
| NATIONAL GRID INTERNATIONAL LIMITED | 02537092 | 01/07/2020 | 01/10/2024 | Gold |
| NATIONAL GRID SEVENTEEN LIMITED | 04492598 | 01/11/2017 | 22/11/2019 | Dissolved |
| NATIONAL GRID THIRTY FIVE LIMITED | 05284987 | 01/11/2017 | 22/11/2019 | Dissolved |
| NATIONAL GRID THIRTY SIX LIMITED | 04611486 | 01/11/2017 | 21/06/2022 | Dissolved |
| NATIONAL GRID TWELVE LIMITED | 04355616 | 01/07/2020 | 01/10/2024 | Not Trading |
| NATIONAL GRID TWENTY-FIVE LIMITED | 07290258 | 01/11/2017 | 22/11/2019 | Dissolved |
| NATIONAL GRID UK LIMITED | 04508773 | 01/07/2020 | 01/10/2024 | Silver |
| NG JERSEY LIMITED | FC035094 | 05/03/2018 | 09/03/2020 | Dissolved |
| NGG FINANCE PLC | 04220381 | 01/07/2020 | 01/10/2024 | Silver |
| NGT TELECOM NO. 1 LIMITED | 03751494 | 01/11/2017 | 05/12/2019 | Dissolved |
| NGT TWO LIMITED | 05234289 | 01/11/2017 | 21/06/2022 | Dissolved |
| THE NATIONAL GRID GROUP QUEST TRUSTEE COMPANY LIMITED | 03297313 | 01/11/2017 | 01/10/2024 | Not Trading |