| Case & Cold Services Limited | Professional & scientific | 1991 |
| Casedwell Limited | Manufacturing | 2025 |
| Caseterix Limited | Information & communication | 2026 |
| Cash COW Automation Limited | Administrative & support | 2021 |
| Cashbury Limited | Professional & scientific | 2025 |
| Cask Aged Ltd | Manufacturing | 2024 |
| Caski Ltd | Information & communication | 2002 |
| Caslau Limited | Professional & scientific | 2020 |
| Caspar Cooks Ltd | Hospitality | 2026 |
| Casperschopa Ltd | Extraterritorial | 2022 |
| Caspian Networks Limited | Hospitality | 1996 |
| Caspian Property Limited | Real estate | 2020 |
| Caspol Limited | Real estate | 2016 |
| Casppa Enterprises Limited | Health & social care | 2017 |
| Casquets Airlines Ltd | Extraterritorial | 2014 |
| Casse Cosmetics Limited | Wholesale & retail | 2026 |
| Cassell Properties Limited | Real estate | 2022 |
| Cassette Group Limited | Education | 2022 |
| Cassinelli Fitness Ltd | Health & social care | 2024 |
| Cassius Group Limited | Professional & scientific | 2025 |
| Cast and Connect CIC | Agriculture & fishing | 2025 |
| Cast Fluid Power Limited | Wholesale & retail | 2022 |
| Castara Resources Limited | Financial services | 2013 |
| Casterton Event Solutions Limited | Administrative & support | 2016 |
| Castle and Keep Ltd | Construction | 2012 |
| Castle Beds 4 YOU Ltd | Construction | 2024 |
| Castle Blinds Bristol Ltd | Administrative & support | 2025 |
| Castle Combe Rally School Limited | Extraterritorial | 2000 |
| Castle Construction (Bristol) Ltd. | Construction | 2002 |
| Castle Court (Dudley) Management Company Limited | Households | 2011 |
| Castle Court Mews Management Limited | Real estate | 2008 |
| Castle Loans Ltd | Financial services | 2013 |
| Castle Moda Limited | Hospitality | 2016 |
| Castle Nominees Limited | Real estate | 2008 |
| Castle Properties (Bristol) Ltd | Real estate | 2020 |
| Castle School Education Trust | Education | 2013 |
| Castle Truck Supplies Limited | Wholesale & retail | 1993 |
| Castle Vets Pet Healthcare Limited | Extraterritorial | 2011 |
| Castlebridge Finance Limited | Financial services | 2020 |
| Castlebridge RX SPV Ltd | Financial services | 2023 |
| Castlebridge SPV Limited | Financial services | 2020 |
| Castledrive Developments Limited | Construction | 2014 |
| Castleforest Audio Ltd | Information & communication | 2025 |
| Castlemead Holdings Limited | Financial services | 2019 |
| Castlemead Insurance Brokers Limited | Financial services | 1987 |
| Castletown Manor Ltd. | Real estate | 2017 |
| Castmech Ltd | Professional & scientific | 2022 |
| Casual Tea Ltd | Hospitality | 2026 |
| Casual Trilogy Limited | Wholesale & retail | 2023 |
| Casus Ltd | Professional & scientific | 2022 |
| Caswell Consulting Ltd. | Health & social care | 2009 |
| Cat GOT the Cream Limited | Wholesale & retail | 2024 |
| Cat Rose Ltd | Arts & recreation | 2022 |
| Cat Stephens Photography Ltd | Professional & scientific | 2018 |
| Cat UK Vehicle Logistics Limited | Wholesale & retail | 1973 |
| Cat-Uk Services Limited | Wholesale & retail | 1986 |
| Cataco Limited | Real estate | 2023 |
| Catalyse Change CIC | Education | 2016 |
| Catalyst at Large Limited | Financial services | 2011 |
| Catalyst Care Group Ltd | Financial services | 2011 |
| Catalyst CCG Limited | Financial services | 2023 |
| Catalyst Training Ltd | Education | 2018 |
| Catalytic AI Ltd | Information & communication | 2025 |
| Catastrophic Overload Ltd | Information & communication | 2019 |
| Catbrain Limited | Wholesale & retail | 2022 |
| Catch 22 Takeaway Limited | Wholesale & retail | 2012 |
| Catch Swim Ltd | Arts & recreation | 2024 |
| Cate Everitt Fundraising Consultancy Ltd | Professional & scientific | 2022 |
| Cate Moore Limited | Professional & scientific | 2011 |
| Category Insights Limited | Professional & scientific | 2003 |
| Category Vehicle Sales & Finance Limited | Wholesale & retail | 2023 |
| Cater Road Cars Ltd | Wholesale & retail | 2019 |
| Cater View Ltd | Hospitality | 2026 |
| Catering Components Ltd | Manufacturing | 1997 |
| Catersigns Limited | Administrative & support | 2008 |
| Cathedral Schools Trust | Education | 2008 |
| Catherine & Akers Limited | Arts & recreation | 2013 |
| Catherines Yard Limited | Real estate | 2022 |
| Catina Design Ltd | Professional & scientific | 2012 |
| Catley's Limited | Hospitality | 2023 |
| Catsoup Industries Ltd | Information & communication | 2025 |
| Cattle Dog House Ltd | Financial services | 2012 |
| Cattron UK Limited | Manufacturing | 1970 |
| Catyamaria Ltd | Administrative & support | 2015 |
| Caudal Peduncle Limited | Agriculture & fishing | 2013 |
| Caudex Ltd | Information & communication | 2026 |
| Caulfield Management Services Limited | Wholesale & retail | 2015 |
| Causeway Accountancy Bristol Limited | Professional & scientific | 2012 |
| Causeway Developments (Hereford) Limited | Real estate | 1995 |
| Cave Capital Ltd. | Information & communication | 2014 |
| Cave Digital Ltd | Information & communication | 2022 |
| Cave Electrical Ltd | Wholesale & retail | 2024 |
| Cave Ware Limited | Information & communication | 2009 |
| Cavendish Court (Cambourne) Management Company Limited | Real estate | 2003 |
| Cavendish Energy Limited | Administrative & support | 2020 |
| Cavendish Estates (Clifton) Ltd | Real estate | 2026 |
| Cavendish Estates Ltd | Real estate | 2020 |
| Cavendish House Operations LLP | | 2009 |
| Cavendish House Recruitment LLP | | 2009 |
| Cavendish House Trading LLP | | 2016 |