| Calibration Dynamics Limited | Extraterritorial | 2005 |
| Calico Soul Band Ltd | Arts & recreation | 2025 |
| Calisacare Limited | Health & social care | 2018 |
| Calke Consulting Ltd | Professional & scientific | 2013 |
| Callogate Ltd | Manufacturing | 2019 |
| Callquest for Care Limited | Health & social care | 2017 |
| Caltech Designs Limited | Professional & scientific | 2017 |
| Calton Investments Limited | Construction | 2018 |
| Calvin Walker Projects Limited | Professional & scientific | 2019 |
| Calypso Pictures Ltd | Information & communication | 2019 |
| Cambridge Interior Design Limited | Professional & scientific | 2024 |
| Cambridge Ztech Limited | Information & communication | 2017 |
| Cambtek Limited | Professional & scientific | 2011 |
| Camden Hill Limited | Real estate | 2024 |
| Cameron Cunningham Limited | Professional & scientific | 2005 |
| Camilla Lambert Project Management Services Limited | Professional & scientific | 2018 |
| Campbell Art Advisory Limited | Wholesale & retail | 2018 |
| Candidly Ltd | Administrative & support | 2020 |
| Candle Technologies Ltd | Information & communication | 2026 |
| Candleford Consulting Ltd | Professional & scientific | 2024 |
| Canine Retreat Ltd | Other services | 2025 |
| Cannon Investments Limited | Administrative & support | 1996 |
| Cannon Services Limited | Administrative & support | 2004 |
| Cannonshot Limited | Real estate | 1980 |
| Canterbury Creative Media Ltd | Professional & scientific | 2020 |
| Cantiaci Limited | Extraterritorial | 2025 |
| Cantium Limited | Professional & scientific | 2018 |
| CAP3D Limited | Financial services | 2020 |
| Capital Funding Partners Ltd | Administrative & support | 2019 |
| Capital Security Group Ltd | Administrative & support | 2016 |
| Capital UK Trading Ltd | Other services | 2024 |
| Capra Renewables Limited | Information & communication | 2024 |
| Caprici Financial Limited | Professional & scientific | 2015 |
| Capstone Consultants Limited | Professional & scientific | 2013 |
| Capture the Event Services Ltd | Professional & scientific | 2013 |
| Capture This Media Limited | Information & communication | 2023 |
| Car Forensics Ltd | Wholesale & retail | 2025 |
| Car Hood Warehouse Limited | Wholesale & retail | 1996 |
| Car Park Assist Ltd | Administrative & support | 2018 |
| Carbonpay Limited | Information & communication | 2020 |
| Carcary Holdings Ltd | Financial services | 2024 |
| Caremore Companions Limited | Health & social care | 2025 |
| Carey's Field Management Company Limited | Households | 1998 |
| Carismor Consulting Limited | Professional & scientific | 2026 |
| Carlton Internet Services Limited | Information & communication | 2002 |
| Carologist Group Ltd | Education | 2024 |
| Carpentry Design Ltd | Manufacturing | 2021 |
| Carrington Building Services Ltd | Construction | 2012 |
| Casa Matrix Ltd | Other services | 2018 |
| Casas Holdings Limited | Real estate | 2020 |
| Case Managed Limited | Extraterritorial | 2025 |
| Casebournes Limited | Manufacturing | 2003 |
| Casey & Associates (Services) Limited | Professional & scientific | 2022 |
| Cashback Traders.Com Ltd | Professional & scientific | 2025 |
| Cashmere Thoughts Limited | Arts & recreation | 2023 |
| CASITA33 Limited | Real estate | 2026 |
| Casstyle Blinds Limited | Extraterritorial | 1998 |
| Cast Developments Limited | Extraterritorial | 2022 |
| Cast Holdco Limited | Financial services | 2025 |
| Cast Propco Ltd | Real estate | 2023 |
| Castech Refrigeration Ltd | Manufacturing | 2014 |
| Castelli UK Limited | Wholesale & retail | 1997 |
| Castello Properties LLP | | 2009 |
| Castle Lifts Ltd | Administrative & support | 2023 |
| Castle Place Freehold Limited | Households | 2013 |
| Castlecomer Properties Limited | Mining & quarrying | 1998 |
| Castlefort Homes Limited | Construction | 2014 |
| Castlemain Corporate Finance Limited | Professional & scientific | 2016 |
| Catalyst Consultation Ltd | Information & communication | 2025 |
| Catchlight Productions Limited | Information & communication | 2004 |
| Caterpillar Homes Limited | Health & social care | 2020 |
| Cato Investments Ltd. | Information & communication | 2015 |
| Cavallo London Limited | Wholesale & retail | 2012 |
| Cavalry Consulting Limited | Administrative & support | 2012 |
| Cavendish Property Consultants Limited | Real estate | 2003 |
| Cavendry Ltd | Construction | 2026 |
| Cayus Limited | Information & communication | 2026 |
| Cazaly Consultants Limited | Real estate | 1996 |
| CB Auxilium Ltd | Wholesale & retail | 2019 |
| Cbtb Investments Company Limited | Real estate | 2022 |
| CC Ecomm Ltd | Wholesale & retail | 2025 |
| CC Piling Ltd | Professional & scientific | 2024 |
| CC Secretaries Limited | Administrative & support | 2010 |
| CCH Resorts Ltd | Real estate | 2025 |
| CCH Summerhill Lane Limited | Construction | 2017 |
| CDK Sales Ltd. | Wholesale & retail | 2011 |
| Cedar (Motor Spares) Limited | Real estate | 1963 |
| Cedar Stores Residents Association Limited | Households | 2003 |
| Cedars Residents Association (Sevenoaks) Limited | Households | 1984 |
| Cedro Ltd | Wholesale & retail | 2021 |
| Cefo CMS Ltd | Construction | 2020 |
| Cefo Group Limited | Financial services | 2020 |
| Cefo Marine Limited | Administrative & support | 2020 |
| Celcon Blocks Limited | Manufacturing | 1984 |
| Celcon Limited | Manufacturing | 1966 |
| Celtic Bookkeepers Ltd | Professional & scientific | 2014 |
| Centaur Estates (Southern) Limited | Construction | 2007 |
| Centered Care Records Limited | Wholesale & retail | 2022 |
| Centre Stage Agency Limited | Arts & recreation | 2017 |
| Centre Stage Clothing Limited | Wholesale & retail | 2022 |