| Cartagrid Limited | Information & communication | 2026 |
| Carter Farncroft Limited | Professional & scientific | 2019 |
| Carter Property Management LLP | | 2024 |
| Carter Property Rentals Ltd | Real estate | 2019 |
| Carter Surveys Ltd | Professional & scientific | 2026 |
| Cartnell Properties (Leeds) Ltd | Real estate | 2023 |
| Carve Architecture (York) Ltd | Professional & scientific | 2026 |
| Carve Architecture LLP | | 2018 |
| CAS Commercial Ltd | Real estate | 2025 |
| Case Key Ltd | Information & communication | 2014 |
| Casey Swales Developments Ltd | Construction | 2021 |
| Casey Swales Group Ltd | Real estate | 2022 |
| Caseyscoffee Limited | Wholesale & retail | 2020 |
| Cash Converters Limited | Extraterritorial | 1992 |
| Cask Crusaders Ltd | Hospitality | 2023 |
| Casling Cleaning Services Limited | Administrative & support | 2002 |
| Cassel Investments Limited | Financial services | 2019 |
| Cassinobattlefields Ltd | Administrative & support | 2012 |
| Casson Properties Limited | Administrative & support | 2016 |
| Cast Iron Services Ltd | Financial services | 2022 |
| Castellum Grange (Colchester) Residents Management Company Limited | Households | 2020 |
| Castelvy Spaniels Ltd | Agriculture & fishing | 2025 |
| Castelyn and Associates Limited | Professional & scientific | 2017 |
| Castle Court Northern RTM Company Limited | Households | 2017 |
| Castle Court Southern RTM Company Limited | Households | 2017 |
| Castle Court Western RTM Company Limited | Households | 2017 |
| Castle Dawson Limited | Professional & scientific | 2011 |
| Castle Electrics (2010) Limited | Wholesale & retail | 2009 |
| Castle Hill (Cottingham) Management Company Limited | Households | 2018 |
| Castle Howard Arboretum Trust | Arts & recreation | 1995 |
| Castle Howard Developments Limited | Construction | 2023 |
| Castle Howard Estate Limited | Wholesale & retail | 1950 |
| Castle Howard Foundation | Arts & recreation | 2023 |
| Castle Keep (Wetherby) Management Company Limited | Households | 2005 |
| Castle Spa Sheena Ltd | Other services | 2022 |
| Castle Sports Camps Ltd | Health & social care | 2026 |
| Castle ST Limited | Real estate | 2019 |
| Castle Tea Rooms (York) Limited | Hospitality | 2019 |
| Castle Vets Limited | Professional & scientific | 2008 |
| Castle View (Netherton) Management Company Limited | Households | 2022 |
| Castlegate Catering (York) Limited | Hospitality | 2014 |
| Castlegate Education Ltd | Education | 2020 |
| Castlegate Holdings Limited | Hospitality | 2016 |
| Castlegate I.T. Limited | Information & communication | 2011 |
| Castlegate Practice Limited | Health & social care | 2020 |
| Castlehead Commercial Services Limited | Professional & scientific | 2022 |
| Castlemead (953) Trowbridge Management Company Limited | Households | 2016 |
| Castlemead (Persimmon 950) Town Trowbridge Limited | Households | 2016 |
| Castlemead (Persimmon 964) Town Trowbridge Limited | Households | 2016 |
| Castlerock Solutions Limited | Professional & scientific | 2004 |
| Castles UK (Mattresses) Limited | Manufacturing | 2007 |
| Castleton Grange (EYE) Residents Management Company Limited | Households | 2023 |
| Cat in the Wall Ltd | Hospitality | 2021 |
| Cat Lane Vans Ltd | Wholesale & retail | 2019 |
| Catalyse Capital Holdings Limited | Financial services | 2022 |
| Catalyse Capital Limited | Information & communication | 2022 |
| Catalyst BI Limited | Wholesale & retail | 2005 |
| Catalyst Cloud Limited | Information & communication | 2024 |
| Catalyst ERP Limited | Information & communication | 2014 |
| Catalyst Holdings Limited | Financial services | 2019 |
| Catalyst Horsaba Limited | Information & communication | 2015 |
| Catalyst Training & Development Limited | Professional & scientific | 2021 |
| Catapolt Limited | Manufacturing | 2023 |
| Categorical Determination Limited | Other services | 2015 |
| Category Marketing Limited | Professional & scientific | 2025 |
| Catenaria Ltd | Professional & scientific | 2013 |
| Cathay Strensall Ltd | Hospitality | 2016 |
| Cathedral Court (Salisbury) Management Company Limited | Households | 2020 |
| Cathedral View (Durham) Management Company Limited | Households | 2018 |
| Catherine Thompson Consultancy Ltd | Professional & scientific | 2020 |
| Catlin Estates Limited | Arts & recreation | 1996 |
| Catronics Ltd | Other services | 2019 |
| Catton Turkeys Limited | Agriculture & fishing | 1977 |
| Caunton Management Holdings Limited | Financial services | 2024 |
| Caunton Management Limited | Real estate | 1992 |
| Causa Ltd | Professional & scientific | 2023 |
| Cave Plumbing & Renewables Limited | Construction | 2010 |
| Cavendish Place (Harrogate) Management Company Limited | Households | 2001 |
| Cavere Group Limited | Professional & scientific | 2008 |
| Cavere Limited | Financial services | 2008 |
| Cavere Property Management Limited | Real estate | 2008 |
| Cawood Poultry Limited | Agriculture & fishing | 2012 |
| Cawood Property Limited | Real estate | 2020 |
| Cawton Heights Farm LLP | | 2025 |
| Caxton Projects Ltd | Professional & scientific | 2011 |
| Caydence Ltd | Wholesale & retail | 2024 |
| Cayton Meadows (Scarborough) Management Company Limited | Real estate | 2020 |
| Cazaly Engineering Limited | Professional & scientific | 2022 |
| CAZNEAUX4 Ltd | Real estate | 2025 |
| CB Affiliate Ltd | Wholesale & retail | 2021 |
| Cbdgo Ltd | Hospitality | 2017 |
| CBM Firewood Ltd | Wholesale & retail | 2023 |
| CC Electric (KMS) Ltd | Construction | 2026 |
| CCL Holdco Limited | Financial services | 2024 |
| CCM Universal Limited | Health & social care | 2022 |
| CCP Financial Consultants Limited | Extraterritorial | 2018 |
| CCW Mahon Limited | Professional & scientific | 2021 |
| CDC & Partners Ltd | Professional & scientific | 2020 |
| CDL Joinery & Construction Ltd | Construction | 2024 |
| CDM Electrical Commissioning Ltd | Professional & scientific | 2023 |