| Cruz Clean Ltd | Manufacturing | 2026 |
| Cryofix Ltd | Professional & scientific | 2006 |
| Crystal Clear Competitions Ltd | Information & communication | 2025 |
| Crystal Clear GT Limited | Manufacturing | 2017 |
| Crystal Mountain Products Limited | Other services | 2002 |
| CS Design Consultants Limited | Professional & scientific | 2002 |
| CS22 Veteran Expeditions CIC | Other services | 2023 |
| CSI Northwest Ltd | Administrative & support | 2018 |
| CSK Hydraulics Limited | Manufacturing | 2022 |
| CSS Hydraulics Limited | Administrative & support | 2021 |
| CST Hydraulics Limited | Extraterritorial | 2022 |
| CSY Hydraulics Limited | Administrative & support | 2022 |
| Ctel Global Limited | Real estate | 2014 |
| CTN Flooring Contractors Limited | Wholesale & retail | 2012 |
| CTS Homes Ltd | Real estate | 2025 |
| CTW UK Limited | Real estate | 2017 |
| Cube Camper Hire Ltd | Administrative & support | 2018 |
| Cubebtl Ltd | Real estate | 2021 |
| Cudworth & Associates Limited | Health & social care | 2023 |
| Cuisine Creators Consultancy Limited | Professional & scientific | 2025 |
| Culkin & Co Plumbing and Heating Ltd | Construction | 2026 |
| Cultured UK Limited | Wholesale & retail | 2014 |
| Cummins Civil Engineering Limited | Construction | 1985 |
| CUR8 Limited | Information & communication | 2025 |
| Curioso Games Limited | Information & communication | 2018 |
| Curious Coach and Consulting Limited | Professional & scientific | 2024 |
| Curious FOX Consultancy Ltd | Wholesale & retail | 2024 |
| Curly Top Productions Ltd | Information & communication | 2009 |
| Currentbody Skin Ltd | Other services | 2024 |
| Currentbody UK Limited | Wholesale & retail | 2024 |
| Curtain Services Ltd | Wholesale & retail | 2004 |
| Curtis James Limited | Administrative & support | 2016 |
| Custom Floor Studio Limited | Wholesale & retail | 2026 |
| Custom Panel Company Limited | Manufacturing | 2025 |
| Custom Worktops UK Ltd | Construction | 2022 |
| Cute Cute Limited | Manufacturing | 2012 |
| Cutler Cleaning Supplies Limited | Wholesale & retail | 1980 |
| Cvcwd Limited | Energy | 2023 |
| Cvjm Limited | Other services | 2022 |
| CW Advisory Services LLP | | 2010 |
| Cyber Quote Limited | Administrative & support | 2010 |
| Cyberlab Consulting Ltd | Information & communication | 2020 |
| Cyberlab One Limited | Extraterritorial | 2025 |
| Cyberlab Security Limited | Information & communication | 1994 |
| D & a Holehouse Builders Limited | Construction | 2003 |
| D & H Construction Limited | Construction | 2021 |
| D & P Quality Construction Ltd | Construction | 2015 |
| D & R Services (UK) Ltd | Manufacturing | 2003 |
| D and L Flack and Sons Limited | Transport & logistics | 2011 |
| D F Broadhead Limited | Construction | 2006 |
| D H Contractors & Shopfitters Ltd | Construction | 2014 |
| D Kennerley Groundwork Ltd | Construction | 2025 |
| D Stokoe Legacy Limited | Professional & scientific | 2026 |
| D Turnock Limited | Construction | 2016 |
| D&D Haulage & Service Ltd | Transport & logistics | 2022 |
| D&V Farms Ltd | Agriculture & fishing | 2020 |
| D'Oro Italiano Ltd | Hospitality | 2026 |
| D. Croft Site Services Limited | Construction | 2004 |
| D.A.M.S Innovation Ltd | Extraterritorial | 2013 |
| D.B.C. Wood (Cheshire) Limited | Real estate | 1978 |
| D.G Bespoke Projects Ltd | Construction | 2025 |
| D.J.Park Ltd | Professional & scientific | 2025 |
| DAB Holdings Limited | Financial services | 2024 |
| DAC Clinical Limited | Health & social care | 2011 |
| DAC Electrical Limited | Construction | 2010 |
| Daisy Tree Montessori Nursery Limited | Education | 2007 |
| Dale Land Management Limited | Real estate | 2020 |
| Dalton Properties (UK) Limited | Real estate | 2001 |
| DAN Pritchard Electrical Limited | Construction | 2019 |
| DAN Syson Limited | Extraterritorial | 2025 |
| Danali Solutions Ltd | Information & communication | 2021 |
| Dance Consultants International LLP | | 2015 |
| Dance Education Limited | Education | 2020 |
| Dancesalsa Ltd | Other services | 2025 |
| Dandelion Head Ltd | Professional & scientific | 2014 |
| Dangerluxe Limited | Extraterritorial | 2018 |
| Daniel Gould & Company Limited | Transport & logistics | 2015 |
| Danielscottkitchens Ltd | Manufacturing | 2014 |
| DAP Bespoke Automotive Limited | Wholesale & retail | 2012 |
| DAP Cars Limited | Wholesale & retail | 2009 |
| Dara House Consultancy Limited | Administrative & support | 2018 |
| Daring Minds Limited | Health & social care | 2020 |
| Dark Side of the Moon Crystal Company Ltd | Wholesale & retail | 2024 |
| Darling Buds Ltd | Education | 2022 |
| Darren Leech Garden and Landscape Services Limited | Administrative & support | 2023 |
| Dartnall Insight Ltd | Professional & scientific | 2025 |
| Dasilver Associates Limited | Professional & scientific | 2025 |
| DAT Collective Ltd | Information & communication | 2025 |
| Data Tycoons Limited | Information & communication | 2024 |
| Datadate Limited | Professional & scientific | 2007 |
| Dave Beal Plastering Services Limited | Construction | 2004 |
| David Bell Leisure Limited | Real estate | 2021 |
| David Birch Consulting Limited | Professional & scientific | 2017 |
| David Crouch Building Limited | Construction | 2007 |
| David Delew & Associates Limited | Professional & scientific | 2020 |
| David Lucas Limited | Professional & scientific | 1994 |
| David Moseley CMC Ltd | Professional & scientific | 2018 |
| David T Hairdressing Ltd | Other services | 2022 |
| David Warburton Limited | Other services | 2015 |
| Davidson Powell Design Limited | Manufacturing | 2002 |