| Casa Property Services of Sheffield Ltd | Construction | 2014 |
| Casa Ryder Property Developments Ltd | Real estate | 2021 |
| Casafia Limited | Health & social care | 2025 |
| Casafia Medical Aesthetics Limited | Health & social care | 2021 |
| Casamaei Limited | Information & communication | 2017 |
| Cascade Multi Academy Trust | Education | 2015 |
| Case Management Solutions Ltd | Health & social care | 2016 |
| Casey Plastering & Drylining Limited | Construction | 2016 |
| Casey Solutions Limited | Wholesale & retail | 2012 |
| Caseys Holdings Limited | Financial services | 2022 |
| Caseys Investments Limited | Real estate | 2022 |
| Cash 4 ANY Phone Ltd | Other services | 2022 |
| Cash 4 ANY Property Ltd | Real estate | 2022 |
| Cash 4 Cards Limited | Wholesale & retail | 2023 |
| Cash Academy Limited | Education | 2025 |
| Cash Money Global Money Transfer Ltd | Financial services | 2016 |
| Cash Stash Ltd | Professional & scientific | 2025 |
| Cashflow Restructured Limited | Other services | 2025 |
| Cashflow Restructuring Limited | Other services | 2017 |
| Casianis Limited | Transport & logistics | 2022 |
| Cask and Club Limited | Hospitality | 2018 |
| Casla Agency Limited | Professional & scientific | 2022 |
| Casmont Property Group Ltd | Real estate | 2024 |
| Caspercat Ltd | Wholesale & retail | 2022 |
| Cassal Restaurants (FOX Valley) Limited | Hospitality | 2015 |
| Cassal Restaurants (Grimsby) Limited | Hospitality | 2026 |
| Cassal Restaurants (Holdings) Limited | Hospitality | 2017 |
| Cassandra Tate Services Ltd | Health & social care | 2024 |
| Cassanell Limited | Real estate | 2013 |
| Cassco Limited | Professional & scientific | 2017 |
| Casse Croute Bakehouse Ltd | Hospitality | 2024 |
| Casson Construction Limited | Construction | 2024 |
| Cassy Marketing Communications Limited | Other services | 1989 |
| Cast Experience Limited | Manufacturing | 2017 |
| Castilli Property Group Limited | Real estate | 2025 |
| Casting & Craft Shop Ltd | Manufacturing | 2024 |
| Castle Brooke Tools (UK) Limited | Wholesale & retail | 1980 |
| Castle Building Services (South Yorkshire) Limited | Construction | 2013 |
| Castle Collexion Ltd | Wholesale & retail | 2024 |
| Castle Contractors and Developments Limited | Construction | 2015 |
| Castle Courtyard Management Company Limited | Households | 2022 |
| Castle Mill Equity Partners Limited | Professional & scientific | 2019 |
| Castle Owen Construction and Property Consultants Limited | Professional & scientific | 2001 |
| Castle Painting and Decorating Limited | Construction | 2014 |
| Castle Scaffolding Solutions Ltd | Construction | 2025 |
| Castle Solutions (Sheffield) Limited | Administrative & support | 2017 |
| Castle Square Corporate Finance Limited | Professional & scientific | 2009 |
| Castle Square Holdings Limited | Financial services | 2019 |
| CASTLE275 Ltd | Hospitality | 2026 |
| Castlebray Services Ltd | Real estate | 2009 |
| Castlebrooke Advisers Limited | Real estate | 2015 |
| Castlebrooke Asset Management Holdings Ltd | Real estate | 2016 |
| Castlebrooke Carry LLP | | 2016 |
| Castlebrooke Developments Limited | Real estate | 2015 |
| Castlebrooke HS Developments LLP | | 2024 |
| Castlebrooke HS2 Developments Limited | Construction | 2019 |
| Castlebrooke Investments Limited | Real estate | 2014 |
| Castlebrooke Landmark Asset Management Limited | Real estate | 2015 |
| Castlecap Asset Management Limited | Real estate | 2016 |
| Castlehill Accommodation Ltd | Administrative & support | 2016 |
| Castlehill Damage Restoration Ltd | Water & waste | 2021 |
| Castlewood Contracts Limited | Construction | 2010 |
| Castolina Trade Limited | Wholesale & retail | 2025 |
| Castree Limited | Professional & scientific | 2010 |
| Castree MMC Limited | Professional & scientific | 2021 |
| Castus Limited | Information & communication | 2007 |
| Cat Boss Limited | Hospitality | 2024 |
| Cat Hill Equine Water Treadmill Ltd | Other services | 2022 |
| Catalin Pana Ltd | Construction | 2026 |
| Catalyst Live Limited | Information & communication | 2020 |
| Catalyst Management Ltd | Professional & scientific | 2026 |
| Catalyst Records Ltd | Information & communication | 2018 |
| Catch 22 Consulting Limited | Professional & scientific | 2008 |
| Catch Food Services Limited | Hospitality | 2024 |
| Catch Fresh Food Limited | Hospitality | 2026 |
| Catcliffe Consulting Limited | Professional & scientific | 2026 |
| Cater Property Group Ltd | Real estate | 2026 |
| Cater PUB Company Ltd | Hospitality | 2026 |
| Caterbram Limited | Construction | 2025 |
| Caterfield SY Ltd | Wholesale & retail | 2019 |
| Catering Compliance Ltd | Hospitality | 2018 |
| Catering for ALL Tastes Limited | Administrative & support | 2014 |
| Caterpillars Tech Limited | Information & communication | 2024 |
| Cath Cafe Ltd | Hospitality | 2025 |
| Cath Properties Ltd | Real estate | 2024 |
| Catherall Construction Limited | Construction | 2025 |
| Catherall Developments Ltd | Construction | 2016 |
| Catherall Group Holdings Ltd | Financial services | 2025 |
| Catherall Homes Limited | Construction | 2025 |
| Catherall Properties Ltd | Construction | 2024 |
| Catherine Hallam Psychology Limited | Health & social care | 2022 |
| Cathy TEW Associates Ltd | Professional & scientific | 2008 |
| Catley Garage Ltd | Wholesale & retail | 2019 |
| Catlives Ltd | Wholesale & retail | 2024 |
| Catrina Healthcare Ltd | Health & social care | 2022 |
| Cats Property Ltd | Real estate | 2020 |
| Catton Taylor (Yorkshire) Ltd | Real estate | 2022 |
| Catton Taylor Ltd | Real estate | 2020 |
| Causeway Charitable Services | Health & social care | 2005 |
| Causeway Films Limited | Information & communication | 2003 |