| Castillo Developments Ltd | Professional & scientific | 2015 |
| Castle Arcade Properties Limited | Real estate | 2024 |
| Castle Chauffeuring &Close Protection Services Ltd | Transport & logistics | 2017 |
| Castle Climate Control Ltd | Construction | 2015 |
| Castle Clinic Consulting Ltd | Education | 2025 |
| Castle Coachworks (Northampton) Holdings Limited | Financial services | 2025 |
| Castle Coachworks (Northampton) Limited | Wholesale & retail | 1996 |
| Castle Coachworks (Northampton) Properties Limited | Real estate | 2015 |
| Castle Conservatories Limited | Construction | 2005 |
| Castle Construction Group Ltd | Construction | 2025 |
| Castle Court Management Limited | Households | 1984 |
| Castle Vehicle Servicing Limited | Wholesale & retail | 2021 |
| Castlemaine Holdings Limited | Real estate | 2022 |
| Castles Home & Garden Services Ltd | Construction | 2022 |
| Castleton Group Holdings Limited | Professional & scientific | 2025 |
| Caston Construction Limited | Construction | 2014 |
| Cat & Wickets Properties Ltd | Real estate | 2018 |
| Cat and ELA Properties Ltd | Financial services | 2017 |
| Cat James Limited | Information & communication | 2004 |
| Cat Kitchens Ltd | Construction | 2023 |
| Cat With a HAT Limited | Arts & recreation | 2022 |
| Cat's Head Industries Limited | Wholesale & retail | 2000 |
| Cat's Head Vintage Limited | Wholesale & retail | 2021 |
| Catalyst Fabrication Services Limited | Manufacturing | 2023 |
| Catalyst Group Services Ltd | Financial services | 2023 |
| Catalyst Heating and Cooling Services Ltd | Construction | 2019 |
| Catalyst Land Solutions Ltd. | Construction | 2014 |
| Catalysts of Change Ltd | Professional & scientific | 2012 |
| Catch the Moment Ltd | Transport & logistics | 2018 |
| Catchfuture Limited | Real estate | 1986 |
| Catella Shoemaker Limited | Manufacturing | 2020 |
| Cater-Serve Wholesale Ltd | Wholesale & retail | 2026 |
| Caterfire Limited | Professional & scientific | 2014 |
| Caterham Capital Limited | Administrative & support | 2003 |
| Catering on Wheels Ltd | Wholesale & retail | 2021 |
| Caterzone Ltd | Manufacturing | 2017 |
| Catford Barbers Ltd | Other services | 2018 |
| Catfoss Recruitment Limited | Administrative & support | 2009 |
| Catherine Place Property 5 Limited | Real estate | 2023 |
| Catom Construction Ltd | Professional & scientific | 2023 |
| Cattle Dog Crossfit Ltd | Arts & recreation | 2017 |
| Cattle Market (Management) Limited | Households | 2006 |
| Catyvitcor Ltd | Construction | 2024 |
| Cauldwell Commercial Limited | Real estate | 2023 |
| Causeway 2000 Limited | Professional & scientific | 2000 |
| Causeway Diner Limited | Hospitality | 2020 |
| Cava Milana Ltd | Wholesale & retail | 2021 |
| Cavaedium Ltd | Construction | 2024 |
| Cavallo Land Limited | Real estate | 2025 |
| Cavalry Cleaning Ltd | Administrative & support | 2015 |
| Cavalry Finance Ltd | Financial services | 2026 |
| Cavan Property Limited | Real estate | 2016 |
| Cavendish Health Ltd | Health & social care | 2015 |
| Cavendish Hepburn Career Management Consultants Limited | Professional & scientific | 2011 |
| Cavener Ltd | Manufacturing | 2007 |
| CAW Solutions Ltd | Information & communication | 2015 |
| Caw-Tech Ltd | Professional & scientific | 2018 |
| Cawley Landscapes Ltd | Professional & scientific | 2018 |
| CB Advanced Engineering Ltd | Manufacturing | 2024 |
| CB Commercial Cleaning Ltd | Administrative & support | 2015 |
| CB Golden Limited | Wholesale & retail | 2025 |
| CB Investments Limited | Real estate | 2026 |
| CB Promotors Limited | Wholesale & retail | 2025 |
| CB Racing Ltd | Other services | 2026 |
| CB Recovery Ltd | Wholesale & retail | 2023 |
| CB Restaurants Ltd | Hospitality | 2024 |
| CBA Associates Limited | Information & communication | 2016 |
| CBA Construction Ltd | Construction | 2025 |
| CBA Trans Ltd | Transport & logistics | 2023 |
| CBE Network Limited | Wholesale & retail | 2026 |
| Cbel Properties Ltd | Real estate | 2024 |
| CBI Construct Ltd | Construction | 2023 |
| CBM Property Limited | Real estate | 2025 |
| CBR Electrical Ltd | Construction | 2023 |
| CBS Building (Midlands) Ltd | Construction | 2024 |
| CBS Design & Construction Limited | Professional & scientific | 2020 |
| CBS Engineering & Heat Treatment Limited | Manufacturing | 2009 |
| CBS Engineering Holdings Limited | Administrative & support | 2011 |
| CC Colours Ltd | Construction | 2025 |
| CC Direct Trading Ltd | Wholesale & retail | 2021 |
| CC Estimating & Drawing Limited | Professional & scientific | 2016 |
| CC Roofing & Maintenance Ltd | Construction | 2025 |
| CC Town Planning Ltd | Professional & scientific | 2015 |
| CCF Limited | Construction | 1982 |
| CCH Glebe Land Limited | Real estate | 2020 |
| CCH Kislingbury Limited | Real estate | 2020 |
| CCH Milton HAM Limited | Real estate | 2021 |
| Cchairsalon Limited | Other services | 2018 |
| CCR Complex Care and Rehabilitation Ltd | Health & social care | 2026 |
| CCR Estate Limited | Real estate | 2024 |
| CCS 1 Limited | Transport & logistics | 2011 |
| CCS Developments (Midlands) Limited | Construction | 2022 |
| CCW Technical Services Ltd | Professional & scientific | 2025 |
| CD GAH Ltd | Construction | 2018 |
| CD Solutions North West Limited | Water & waste | 2014 |
| Cda-Trans Limited | Transport & logistics | 2017 |
| CDB Civil Engineering Ltd | Construction | 2018 |
| CDI Global Ltd | Education | 2017 |
| CDJ Transport Ltd | Transport & logistics | 2025 |
| CDM Delivery Ltd | Transport & logistics | 2019 |