| British Gas Trading Limited | 5000 to 19,999 staff | 5.2% | 36.7% |
| Bwsc Generation Services Northern Ireland Ltd | Less than 250 staff | 20.3% | 0.0% |
| Bwsc Generation Services UK Ltd | 250 to 499 staff | 22.3% | 3.7% |
| Cadent Gas Limited | 5000 to 19,999 staff | 17.0% | 20.3% |
| Centrica PLC | 1000 to 4999 staff | 18.6% | 33.5% |
| Clarke Energy Limited | 250 to 499 staff | 18.2% | 15.6% |
| Corona Energy Retail 1 Limited | 250 to 499 staff | 6.5% | 38.1% |
| Daikin Airconditioning UK Limited | 250 to 499 staff | 26.0% | 19.2% |
| Drax Energy Solutions Limited | 250 to 499 staff | 25.0% | 32.0% |
| Drax Power Limited | 1000 to 4999 staff | 14.9% | 26.7% |
| E.on UK Limited | 5000 to 19,999 staff | 24.1% | 36.8% |
| Edf Energy Customers Limited | 500 to 999 staff | 27.3% | 8.8% |
| Edf Energy Limited | 5000 to 19,999 staff | 27.5% | 28.2% |
| Edf Energy Nuclear Generation Limited | 5000 to 19,999 staff | 9.3% | 13.9% |
| Edf Energy Renewables Limited | 500 to 999 staff | 1.5% | 36.9% |
| Electricity North West Limited | 1000 to 4999 staff | 10.2% | 16.0% |
| Engie UK Limited | Less than 250 staff | 26.3% | 23.9% |
| Equans Fm Limited | 500 to 999 staff | 34.1% | 14.8% |
| First Hydro Company | Less than 250 staff | 30.1% | 4.8% |
| Good Energy Limited | 250 to 499 staff | 20.3% | 40.0% |
| Lightsource Development Services Limited | 250 to 499 staff | 5.5% | 44.0% |
| Londonenergy Ltd | 250 to 499 staff | 0.0% | 15.2% |
| Love Business Group Limited | 250 to 499 staff | 0.0% | 43.7% |
| National Gas Transmission PLC | 1000 to 4999 staff | 0.1% | 25.5% |
| National Grid Electricity Distribution (East Midlands) PLC | 1000 to 4999 staff | 7.8% | 18.8% |
| National Grid Electricity Distribution (South Wales) PLC | 1000 to 4999 staff | 10.1% | 8.1% |
| National Grid Electricity Distribution (South West) PLC | 1000 to 4999 staff | 9.4% | 11.5% |
| National Grid Electricity Distribution (West Midlands) PLC | 1000 to 4999 staff | 3.6% | 11.9% |
| National Grid Electricity Transmission PLC | 1000 to 4999 staff | 4.6% | 24.1% |
| Northern Powergrid (Northeast) PLC | 1000 to 4999 staff | 29.9% | 13.0% |
| Northern Powergrid (Yorkshire) PLC | 1000 to 4999 staff | 13.2% | 11.0% |
| Octopus Energy Limited | 1000 to 4999 staff | 1.3% | 48.4% |
| Orsted Power (UK) Limited | 1000 to 4999 staff | -7.4% | 24.4% |
| Px Limited | 500 to 999 staff | 23.6% | 12.6% |
| Rwe Generation UK PLC | 500 to 999 staff | 9.2% | 15.7% |
| Scotland Gas Networks PLC | Less than 250 staff | 12.9% | 8.0% |
| Scottish And Southern Energy Power Distribution Limited | 250 to 499 staff | 16.4% | 0.0% |
| Scottish Hydro Electric Power Distribution PLC | 1000 to 4999 staff | 4.0% | 17.3% |
| Scottish Hydro Electric Transmission PLC | 1000 to 4999 staff | 13.4% | 22.5% |
| Scottishpower Energy Retail Limited | 500 to 999 staff | 12.9% | 37.0% |
| Scottishpower Renewables (UK) Limited | 500 to 999 staff | 10.3% | 26.0% |
| Sefe Energy Limited | Less than 250 staff | 13.5% | 35.0% |
| Sefe Marketing & Trading Limited | 250 to 499 staff | 24.0% | 15.2% |
| Severn Waste Services Limited | 250 to 499 staff | 5.9% | 8.8% |
| Smartestenergy Limited | 500 to 999 staff | 25.6% | 29.0% |
| So Energy Trading Limited | 250 to 499 staff | 10.0% | 29.4% |
| Southern Electric Power Distribution PLC | 1000 to 4999 staff | 4.7% | 19.1% |
| Southern Gas Networks PLC | 250 to 499 staff | 7.9% | 6.0% |
| Sp Distribution PLC | 500 to 999 staff | 7.2% | 14.0% |
| Sp Manweb PLC | 500 to 999 staff | 11.5% | 10.0% |
| Sp Transmission PLC | 500 to 999 staff | 10.7% | 14.0% |
| Sse Airtricity Energy Supply (Ni) Limited | 250 to 499 staff | -4.2% | 40.5% |
| Sse Energy Supply Limited | 1000 to 4999 staff | 18.2% | 32.6% |
| Sse Renewables Services (UK) Limited | 1000 to 4999 staff | 10.7% | 18.2% |
| Sse Thermal Energy Operations Limited | 250 to 499 staff | 27.7% | 18.8% |
| Sse Utility Solutions Limited | 250 to 499 staff | 20.8% | 17.0% |
| Storengy UK Limited | Less than 250 staff | 15.2% | 0.0% |
| The Freedom Group Of Companies LTD. | 500 to 999 staff | 28.9% | 9.8% |
| Totalenergies Gas & Power Limited | 500 to 999 staff | 12.0% | 21.1% |
| UK Power Networks (Operations) Limited | 5000 to 19,999 staff | 14.7% | 13.5% |
| Uniper UK Limited | 500 to 999 staff | 9.9% | 15.5% |
| United Infrastructure Power T&d Limited | 250 to 499 staff | 42.2% | 3.0% |
| Utilita Energy Limited | 500 to 999 staff | 3.6% | 36.0% |
| Vattenfall Wind Power Ltd | 250 to 499 staff | 10.0% | 30.7% |
| Veolia Energy & Utility Services UK Limited | 250 to 499 staff | 34.4% | 8.8% |
| Vital Energi Utilities Limited | 500 to 999 staff | 38.2% | 7.8% |
| Vpi Holding Limited | 250 to 499 staff | 15.8% | 5.3% |
| Wales & West Utilities Limited | 1000 to 4999 staff | 6.0% | 15.0% |
| Western Biomass Operating Company Limited | Less than 250 staff | 27.3% | 0.0% |
| YĆ¼ Energy Retail Limited | 250 to 499 staff | -22.9% | 22.2% |