| CT Cuisine Limited | Hospitality | 2023 |
| CT MED Ltd | Health & social care | 2026 |
| Ctgbd Property Ltd | Real estate | 2026 |
| Cullen & Mclean Holdings Limited | Financial services | 2019 |
| Cullen & Mclean Sourcing Limited | Professional & scientific | 2012 |
| Cullen's Catering Limited | Hospitality | 2012 |
| Cullens at the Cabin Limited | Hospitality | 2026 |
| Culmhead Business Park (Management Co.) Limited | Other services | 2003 |
| Culmhead Caravans Limited | Wholesale & retail | 2022 |
| Culmvale Farming Ltd | Financial services | 2023 |
| Cultura Capital Limited | Education | 2023 |
| Cultural Agility Sessions Ltd | Information & communication | 2020 |
| Culturalinks Community CIC | Professional & scientific | 2025 |
| Cunliffebright Limited | Professional & scientific | 2018 |
| Cureton Medical Services Ltd | Health & social care | 2021 |
| Curlew Medical Limited | Health & social care | 2022 |
| Curload Consultants Limited | Professional & scientific | 2009 |
| Curly Cottage Media Limited | Information & communication | 2013 |
| Curtabemdoodles Ltd | Agriculture & fishing | 2021 |
| Curtis Agricultural Limited | Agriculture & fishing | 2023 |
| Curtis Pitts Deer Services Ltd | Agriculture & fishing | 2025 |
| Curtis Tractors Limited | Agriculture & fishing | 2023 |
| Cushion Financial Limited | Financial services | 2019 |
| Customer PI Limited | Professional & scientific | 2022 |
| CUT NO Corners Limited | Administrative & support | 2011 |
| Cuthbert Tree Care Ltd | Agriculture & fishing | 2026 |
| Cutler Enterprises Limited | Hospitality | 2024 |
| CW Creation Group Ltd | Arts & recreation | 2024 |
| CW Trade Limited | Manufacturing | 2014 |
| CWS Racing Ltd | Professional & scientific | 2004 |
| Cyber FOX Limited | Information & communication | 2016 |
| Cyber Risk Management Group Limited | Information & communication | 2018 |
| Cyberfirm Limited | Extraterritorial | 2004 |
| Cybernetic Industries Ltd | Information & communication | 2024 |
| Cybervector Limited | Professional & scientific | 2011 |
| Cygnet House Vets Ltd | Professional & scientific | 2025 |
| CZ Property Holdings Limited | Real estate | 2020 |
| D & G Widden LLP | | 2018 |
| D & H Jones Properties Ltd | Real estate | 2022 |
| D & N Autogas Limited | Wholesale & retail | 2001 |
| D & S Agricultural Engineers Limited | Wholesale & retail | 2006 |
| D Birt & Company Limited | Professional & scientific | 2004 |
| D Burton Bricklayers Ltd | Construction | 2015 |
| D C & L Barrett Ltd | Wholesale & retail | 2023 |
| D Diems International Ltd | Wholesale & retail | 2024 |
| D Evans & SON Building Contractor Ltd | Construction | 2022 |
| D Glass (Yeovil) Limited | Professional & scientific | 2001 |
| D H Patten Limited | Agriculture & fishing | 2023 |
| D J B Machinery Compliance Ltd | Professional & scientific | 2017 |
| D J Hall Property Management Limited | Real estate | 2017 |
| D J Property Developments Limited | Construction | 2012 |
| D P Carpentry Limited | Construction | 2010 |
| D R Veterinary Services Limited | Professional & scientific | 2020 |
| D Stephens & Sons (Luckyard) Limited | Agriculture & fishing | 1988 |
| D T Electrical SW Limited | Energy | 2014 |
| D Whitworth Construction Limited | Construction | 2021 |
| D&C Barnes Construction Ltd | Construction | 2019 |
| D'Loummmies CIC | Education | 2023 |
| D'Urberville Vineyard Limited | Manufacturing | 2016 |
| D.E.A Property Ltd | Real estate | 2018 |
| D.R.W. Reddaway Ltd | Agriculture & fishing | 2003 |
| D.S. (HR) Limited | Professional & scientific | 2007 |
| D1NNER Limited | Health & social care | 2022 |
| D1SRUPT Ltd | Professional & scientific | 2021 |
| Daems Nederland LLP | | 2015 |
| Daffodil PR and Communications Limited | Professional & scientific | 2018 |
| Dagelia Ltd | Health & social care | 2011 |
| Daglish Co Limited | Financial services | 2025 |
| Daich Limited | Real estate | 2001 |
| Daily Needs Food and Wine Limited | Wholesale & retail | 2013 |
| Daily Needs Foods UK Ltd | Wholesale & retail | 2026 |
| Daisy Farm Produce Ltd | Extraterritorial | 2017 |
| Dakk Holdings Limited | Financial services | 2024 |
| DAL Electrical SW Ltd | Construction | 2024 |
| Dale Maggs Farrier Limited | Other services | 2012 |
| Dale Racing (Logistics) Ltd | Transport & logistics | 2013 |
| Dalir Property Limited | Real estate | 2020 |
| Dampier - Hill Developments Ltd | Construction | 2021 |
| DAN Alexandru Florea Ltd | Health & social care | 2015 |
| DAN Crowther Ltd | Administrative & support | 2023 |
| DAN Duddridge Services Limited | Administrative & support | 2023 |
| DAN Filip Limited | Wholesale & retail | 2024 |
| DAN Hobbs Ltd | Professional & scientific | 2024 |
| DAN Jones & Creative Associates Limited | Information & communication | 2026 |
| DAN White Engineering Services Ltd | Professional & scientific | 2022 |
| Danae Capital Limited | Financial services | 2020 |
| Dancing Lemur Studios Ltd | Wholesale & retail | 2024 |
| Dandelion Seeds Ltd | Professional & scientific | 2018 |
| Dandelion Worldwide Limited | Real estate | 2007 |
| Dangun Bristol Ltd | Hospitality | 2017 |
| Daniel Howe Ltd | Wholesale & retail | 2017 |
| Daniel WIN Limited | Other services | 2000 |
| Daniells Family Law Limited | Professional & scientific | 2015 |
| Danimar Limited | Health & social care | 2019 |
| Darcy JAY Ltd | Administrative & support | 2019 |
| Daren Partridge Limited | Professional & scientific | 2002 |
| Darren Alan Ward Ltd | Extraterritorial | 2022 |
| Darren Blows Carpentry Limited | Construction | 2011 |
| Darwin Innovation Limited | Information & communication | 2008 |
| Dash - Hyphen Limited | Financial services | 2016 |