| Candide Farms LLP | | 2022 |
| Candy Group Limited | Financial services | 2015 |
| Candy Melts Mini Market Ltd | Wholesale & retail | 2024 |
| Candy Professional Services Ltd | Professional & scientific | 2012 |
| Cannabotech UK Ltd | Other services | 2020 |
| Cannon Classic Cars Limited | Wholesale & retail | 2025 |
| Canterbury Court (Phase II) Management Company Limited | Households | 2002 |
| CAO Global Limited | Transport & logistics | 2024 |
| Capella Computer Solutions Ltd | Information & communication | 2018 |
| Capital & General (UK) Limited | Construction | 2007 |
| Capital Belting Holdings (UK) Limited | Financial services | 2025 |
| Capital Belting Limited | Manufacturing | 2015 |
| Capital Chauffeurs Ltd | Transport & logistics | 2024 |
| Capital Conflict Management CIC | Public administration | 2008 |
| Capital Global Freight Forwarding Ltd | Transport & logistics | 2023 |
| Capital Infrastructure Limited | Professional & scientific | 2007 |
| Capital Property Investments Ltd | Real estate | 2006 |
| Capital Sustainable Innovation Ltd | Professional & scientific | 2023 |
| Capital Tax Accountants Limited | Professional & scientific | 2000 |
| Capital Tax Consulting Ltd | Professional & scientific | 2011 |
| Capitalquarry Ltd | Financial services | 2025 |
| Capitopia Limited | Real estate | 2024 |
| Capone Electrical & Sons Ltd | Construction | 2023 |
| Capri Brit One Limited | Real estate | 2016 |
| Capscan Imaging Ltd | Health & social care | 2023 |
| Captain's Badge Ltd | Arts & recreation | 2025 |
| Captems Ltd | Information & communication | 2025 |
| Car Finance R US Ltd | Financial services | 2017 |
| CAR2YOUSERVICE Ltd | Wholesale & retail | 2026 |
| Carabel Homes LLP | | 2014 |
| Carabel Properties Ltd | Real estate | 2018 |
| Caravall Ltd | Professional & scientific | 2015 |
| Care Bridge Solutions Ltd | Public administration | 2025 |
| Care by Lily Limited | Health & social care | 2024 |
| Carecommitted Limited | Health & social care | 2021 |
| Career Personnel (London) Ltd | Administrative & support | 2019 |
| Career Tech Limited | Education | 2021 |
| Caremarque Ltd | Other services | 2017 |
| Carenest Solutions Ltd | Administrative & support | 2022 |
| Careplus Pharmacy Limited | Wholesale & retail | 2011 |
| Careprogress Limited | Health & social care | 1999 |
| Caribou Nest Ltd | Real estate | 2025 |
| Carina Enterprises Limited | Professional & scientific | 2021 |
| Caring Kindly Limited | Administrative & support | 2025 |
| Carisbrooke House (Northwood) Management Company Limited | Households | 2007 |
| Carisbrooke House Freeholders Limited | Households | 2009 |
| Carl Knight Motor Services Ltd | Wholesale & retail | 2016 |
| Carlsen & Betner Limited | Information & communication | 2014 |
| Carlton Hill Construction Limited | Construction | 2023 |
| Carlton Hill Renovations LLP | | 2023 |
| Carlton Residents Management Limited | Households | 1968 |
| Carlton Star Ltd | Real estate | 2024 |
| Carltpool Limited | Wholesale & retail | 2018 |
| Caroe Court Limited | Households | 1998 |
| Carol Giles Consultancy Ltd | Professional & scientific | 2021 |
| Carolann Properties Limited | Construction | 2007 |
| Carpediam Diamonds Ltd | Wholesale & retail | 2010 |
| Carpet Charmers Ltd | Construction | 2025 |
| Carpet London Ltd | Administrative & support | 2025 |
| Carpet M Ltd | Administrative & support | 2025 |
| Carrie Chappell Coaching Ltd | Administrative & support | 2021 |
| Carrington Services (UK) Ltd | Other services | 2012 |
| Carrowheane Ltd | Construction | 2017 |
| Carter & Co (Stretton) Ltd | Hospitality | 2018 |
| Carter & Co Bars Ltd | Hospitality | 2020 |
| Carter Court Management Limited | Households | 1996 |
| Carter Gregson Gray Ltd | Professional & scientific | 2022 |
| Carter Reid Limited | Other services | 2017 |
| Cartland Limited | Wholesale & retail | 1990 |
| CAS Advisory Ltd | Professional & scientific | 2019 |
| Casa Virtue Ltd | Wholesale & retail | 2024 |
| Casc Limited | Manufacturing | 2023 |
| Casetone Solutions Limited | Information & communication | 2017 |
| Casey & Sons Roofing Ltd | Construction | 2025 |
| Caseyfierro Limited | Professional & scientific | 2015 |
| CASH4EVENTS Ltd | Administrative & support | 2021 |
| Cast Heating & Plumbing Ltd | Construction | 2007 |
| Castle Enterprises 1882 Ltd | Professional & scientific | 2023 |
| Castle Road Homes Limited | Real estate | 2007 |
| Castlebar Global Ltd | Wholesale & retail | 2020 |
| Castlewood Holdco Limited | Financial services | 2019 |
| Cat 89 Ltd | Construction | 2017 |
| Cat Cloud Ltd | Health & social care | 2022 |
| Cata Homes&Son Ltd | Construction | 2025 |
| Catalyst Spirits Limited | Professional & scientific | 2021 |
| Catch the Cat Marketing Limited | Professional & scientific | 2018 |
| Caterpillars Preschool (Coldean) Ltd | Education | 2009 |
| Cava Spiliadis UK Limited | Wholesale & retail | 2015 |
| Cayo Investment Ltd | Real estate | 2017 |
| CBG Contracts Ltd | Construction | 2016 |
| Cbie Limited | Administrative & support | 2003 |
| CBM Woodwork Ltd | Manufacturing | 2019 |
| Cbnservices Ltd | Administrative & support | 2026 |
| CBR Interiors Limited | Professional & scientific | 2006 |
| Cbuns Ltd | Arts & recreation | 2021 |
| Ccadkl Limited | Real estate | 2026 |
| CCL (WT) Newco 4 Limited | Financial services | 2016 |
| CCS Creative Consulting Ltd | Arts & recreation | 2014 |
| CD Leasing Limited | Real estate | 2016 |
| CD Rail Services Ltd | Construction | 2020 |