| Cluetropolis Ltd | Rickmansworth | 2016 |
| Clumber Park Racing Ltd | Notts | 2005 |
| Cluny Activities Trading Ltd | Cluny | 2014 |
| Clusterflux Ltd | London | 2022 |
| Clusterfun Productions Ltd | Birmingham | 2026 |
| Clutch GG Media Limited | Birmingham | 2021 |
| Clutch Ltd | London | 2025 |
| Clutch Pro Tour Limited | Hassocks | 2021 |
| Clutter Cards Ltd | London | 2024 |
| CLW Art Limited | London | 2014 |
| CLW Coaching Limited | Rotherham | 2025 |
| Clwb Chwaraeon Ffestiniog Limited | Blaenau Ffestiniog | 1999 |
| Clwb Chwaraeon Seilo CYF | Y Felinheli | 2021 |
| Clwb Chwareuon Madog CYF. | Gwynedd | 1994 |
| Clwb Golff Aberteifi Masnachu CYF | Cardigan | 2021 |
| Clwb Golff Aberystwyth Golf Club Limited | Aberystwyth | 2011 |
| Clwb Golff Caerfyrddin - Carmarthen Golf Club Ltd | Carmarthen | 2023 |
| Clwb Golff Fairbourne Ltd | Fairbourne | 2025 |
| Clwb Golff Glynhir Golf Club Limited | Ammanford | 2022 |
| Clwb Music CYF | Cardiff | 2020 |
| Clwb Padel Limited | Cardiff | 2024 |
| Clwb PEL Droed Aberaeron Football Club Ltd | Aberaeron | 2019 |
| Clwb Pel-Droed Llanystumdwy CYF | Porthmadog | 2016 |
| Clwb Peldroed Llandeilo AFC CYF | Llandeilo | 2022 |
| Clwb Peldroed Penmachno Limited | Betws-Y-Coed | 2014 |
| Clwb Rygbi Aberteifi CYF | Cardigan | 2023 |
| Clwb Rygbi Bethesda CYF | Bangor | 2016 |
| Clwb Rygbi Betws RFC Limited | Ammanford | 2012 |
| Clwb Rygbi BRO Gwernant Ltd | Ellice Way | 2025 |
| Clwb Rygbi Brynaman Limited | Ammanford | 2018 |
| Clwb Rygbi Caernarfon Cyfyngedig | Caernarfon | 2012 |
| Clwb Rygbi Crymych CYF | Crymych | 2016 |
| Clwb Rygbi Cymry Caerdydd Cyfyngedig | Cardiff | 2009 |
| Clwb Rygbi Dolgellau CYF | Dolgellau | 2015 |
| Clwb Rygbi Ieuenctid Cwins Cymraeg Caerdydd CYF | Cardiff | 2016 |
| Clwb Rygbi Llambed Cyfyngedig | Lampeter | 2005 |
| Clwb Rygbi Llangefni CYF | Llangefni | 2015 |
| Clwb Rygbi Pen-Y-Bont AR Ogwr Limited | Bridgend | 2018 |
| Clwb Rygbi Pontiets Limited | Pontyates | 2018 |
| Clwb Rygbi Rhos CYF | Wrexham | 2018 |
| Clwb Rygbi Rhuthun CYF | Ruthin | 2015 |
| Clwb Rygbi Y Bala CYF | Y Bala | 2016 |
| Clwb Rygbi Y Tymbl CYF | Llandeilo | 2015 |
| Clwb Rygbi Ystradgynlais Ltd | Swansea | 2017 |
| Clwb Trotian Tregaron Cyfyngedig | Ceredigion | 2003 |
| Clwyd Fine Arts Trust(The) | St Asaph | 1985 |
| Clwydian Fitness Ltd | Rhyl | 2023 |
| Clxr Limited | Wilmslow | 2025 |
| Clydach Community Gardens CIC | Swansea | 2025 |
| Clydach Football Club CIC | Swansea | 2025 |
| Clyde Competitions Ltd | Kilmarnock | 2023 |
| Clyde Cruising Club Limited | Glasgow | 2012 |
| Clyde Fight Academy Ltd | Gourock | 2023 |
| Clyde Leisure Limited | | 1996 |
| Clyde Marina Limited | Ayrshire | 1995 |
| Clyde Marina North Limited | Ardrossan | 2020 |
| Clyde Maritime Centre Limited | Glasgow | 1992 |
| Clyde MÒD Studios CIC | Glasgow | 2024 |
| Clyde Studios Ltd | Ayr | 2013 |
| Clyde Unity Theatre | Glasgow | 1989 |
| Clyde Valley Family Park Limited | East Lothian | 2018 |
| Clyde Youth Theatre Productions Ltd | Greenock | 2024 |
| Clydebank Community Sports Hub | Clydebank | 2013 |
| Clydebank Football Club Limited | Glasgow | 2018 |
| Clydebank Holdings Limited | | 2000 |
| Clydebuilt Festival CIC | Glasgow | 2023 |
| Clydeside Films Ltd | London | 2024 |
| Clydeside Tapestry Ltd | Edinburgh | 2025 |
| Clydewin Competitions Ltd. | Glasgow | 2025 |
| Clym Studio Limited | Edgware | 2014 |
| Clynchmob Ltd | Coalville | 2020 |
| Clyne Golf Club Limited | Swansea | 1920 |
| Clyne Heritage Society | Brora | 2017 |
| Clyne Valley Community Project | Swansea | 2011 |
| Clynmelyn Limited | London | 2019 |
| Clyst Hydon Cricket & Sports Club | Cullompton | 2022 |
| Clyst Hydon Swimming Club | Cullompton | 2006 |
| Clyvale Media Limited | Wembley | 2003 |
| CM 1991 Ltd | Glasgow | 2021 |
| CM Adventure UK Ltd | Letchworth Garden City | 2019 |
| CM Basma Ltd | London | 2025 |
| CM Bull Ltd | London | 2023 |
| CM Community Ltd Ltd | Ilford | 2024 |
| CM Dollar Limited | London | 2017 |
| CM Entertainment Services Ltd | Stafford | 2024 |
| CM Entertainments Limited | Preston | 2016 |
| CM Fitness & Training Ltd | Peacehaven | 2022 |
| CM Football Consultancy Ltd | Huddersfield | 2025 |
| CM Futsal Academy Ltd | London | 2013 |
| CM Good Limited | Worthing | 2018 |
| CM Griffin Services Ltd | London | 2021 |
| CM Health & Fitness Ltd | Wigan | 2013 |
| CM Management Limited | Banbury | 2017 |
| CM Media 85 Ltd | Lisburn | 2026 |
| CM Mgmt Ltd | London | 2021 |
| CM Prime Ltd | London | 2013 |
| CM Production Management Ltd | Barking | 2016 |
| CM Racing Ltd | Northampton | 2025 |
| CM Sporting Club Limited | Wokingham | 2022 |
| CM Sporting Limited | Cupar | 2022 |