| C.I.E.89 Ltd | Transport & logistics | 2025 |
| C.Lee Investments Ltd | Real estate | 2019 |
| C.M.F. Consultancy Services Limited | Professional & scientific | 1997 |
| C.N.R Property Ltd | Real estate | 2025 |
| C.S Pipetech Ltd | Construction | 2015 |
| C.Vban Ltd | Transport & logistics | 2021 |
| C2 Build Limited | Real estate | 2003 |
| C2 Safety (South Yorkshire) Ltd | Administrative & support | 2002 |
| C3 Architectural Planning and Design Limited | Professional & scientific | 2018 |
| C3R Technologies Limited | Manufacturing | 2023 |
| C4 Communication Benelux Limited | Construction | 2006 |
| CA Manufacturing Solutions Ltd | Professional & scientific | 2024 |
| CA Wealth Management Limited | Professional & scientific | 2018 |
| CA Wills Ltd | Professional & scientific | 2025 |
| Ca&O Retail Ltd | Wholesale & retail | 2025 |
| Caballero Bespoke Ltd | Wholesale & retail | 2021 |
| Cabana.Neagra Ltd | Transport & logistics | 2023 |
| Cabbie Coach Limited | Education | 2025 |
| Cable Safe Limited | Manufacturing | 2000 |
| Cablelincs Limited | Information & communication | 2023 |
| Cabot Industries Ltd | Extraterritorial | 2012 |
| Cabwi Awarding Body | Education | 1991 |
| Cabwi Awarding Body Trading Limited | Education | 2022 |
| Cacao Partners Ltd | Wholesale & retail | 2018 |
| CAD Coaching Ltd | Education | 2025 |
| Cadman Funeral Services Limited | Other services | 2010 |
| Cadventure (Europe) Limited | Professional & scientific | 1994 |
| Cafe Cocktail Ltd | Hospitality | 2018 |
| Cafe Express Ltd | Extraterritorial | 2015 |
| Cafe on the Corner Limited | Hospitality | 2020 |
| Cafe Totem Limited | Hospitality | 2017 |
| CAFE28 at the Mill Ltd | Hospitality | 2024 |
| Cahill Consultants Ltd | Real estate | 2019 |
| Cairns Joinery Ltd | Construction | 2026 |
| Cairns TM Ltd | Construction | 2024 |
| Cakc Music Ltd | Information & communication | 2021 |
| CAL Centre Project | Health & social care | 2012 |
| Calder & Finch Ltd | Extraterritorial | 2026 |
| Calderstone Group Ltd | Extraterritorial | 2026 |
| Caldrion Group Ltd | Extraterritorial | 2026 |
| Cali Cutz Limited | Other services | 2021 |
| Calibre Surfacing and Driveways Limited | Construction | 2019 |
| California Mission Limited | Information & communication | 2026 |
| Calista Properties Limited | Real estate | 2022 |
| Calladine Roofing Limited | Construction | 2016 |
| Callide Senior Management Limited | Administrative & support | 2005 |
| Callo Cafe Ltd | Hospitality | 2026 |
| Calls Landing Ltd | Financial services | 2025 |
| Cally London Ltd | Manufacturing | 2026 |
| Calm Circuit Ltd | Information & communication | 2025 |
| Calm Pelican Ltd | Arts & recreation | 2025 |
| Calmpawz Ltd | Professional & scientific | 2021 |
| Calvani Healthcare Ltd | Health & social care | 2022 |
| Calzados Boreal UK Limited | Wholesale & retail | 2021 |
| CAM Coaching Ltd | Education | 2024 |
| CAM Coffee Club Ltd | Hospitality | 2023 |
| CAM Funding Solutions Ltd | Financial services | 2019 |
| Camberwella International Ltd | Financial services | 2019 |
| Cambeth Community Project C.I.C. | Health & social care | 2020 |
| Cambleforth Limited | Construction | 1992 |
| Cambourne Properties Ltd | Households | 2025 |
| Cambria Sports Culture CIC | Education | 2021 |
| Cambridge Laser Clinic Ltd | Extraterritorial | 2010 |
| Camden Sloane 2 Ltd | Construction | 2023 |
| Camden Sloane Limited | Construction | 2019 |
| Camel Collective Limited | Wholesale & retail | 2025 |
| Camelia Fragrance Ltd | Wholesale & retail | 2025 |
| Cameron Shaw TM Ltd | Public administration | 2025 |
| Camille Communication Ltd | Extraterritorial | 2025 |
| Camion Transport Ltd | Transport & logistics | 2020 |
| Campbell & Stenton Ltd | Professional & scientific | 2011 |
| Campbell Design & Engineering Limited | Manufacturing | 1997 |
| Campbell Living Limited | Real estate | 2021 |
| Camy Medical Ltd | Health & social care | 2012 |
| Canal Side Developments Limited | Real estate | 2001 |
| Canal View 1965 Limited | Extraterritorial | 2014 |
| Canberra House TDC Ltd | Real estate | 2012 |
| Candid Hire Ltd | Administrative & support | 2025 |
| Candlecraft Ltd | Wholesale & retail | 2019 |
| Cando Pizza Limited | Hospitality | 2026 |
| Cands Diving Supplies Ltd | Wholesale & retail | 2016 |
| Candy Island Sweets Ltd | Wholesale & retail | 2021 |
| Canine Paradise Limited | Other services | 2007 |
| Canine Sports Support Ltd | Professional & scientific | 2012 |
| Canon (Yorks) Construction Ltd | Construction | 2022 |
| Cansum Beauty Ltd | Hospitality | 2021 |
| Cantilever House Ltd | Real estate | 2020 |
| Cantley Barbers Limited | Other services | 2022 |
| Cantley House Ltd | Households | 2022 |
| Cantley SH Limited | Wholesale & retail | 2020 |
| CAP IT Managed Services Ltd | Information & communication | 2013 |
| Capiens Limited | Wholesale & retail | 2018 |
| Capital Housing Solutions Ltd | Real estate | 2025 |
| Capital SEC Solutions Ltd | Administrative & support | 2019 |
| Capital UK Investment Solutions Ltd | Real estate | 2016 |
| Capman Ltd | Financial services | 2015 |
| Capricorn Technical Services Ltd | Administrative & support | 2015 |
| Caprina Holdings Ltd | Financial services | 2024 |
| Caprina Limited | Water & waste | 1986 |
| Caprina Trading Limited | Hospitality | 2007 |