| Crunchspark Advisory Limited | Professional & scientific | 2023 |
| Crusade Home Improvements Ltd | Construction | 2026 |
| Crusaders Community Basketball CIC | Arts & recreation | 2022 |
| Crxss Limited | Administrative & support | 2018 |
| Cryptodata Live Limited | Professional & scientific | 2021 |
| Crystal Domestic Limited | Administrative & support | 2009 |
| CS Nominees Limited | Administrative & support | 2017 |
| CSJ Clerk of Works Services Limited | Construction | 2018 |
| CT Barbell Limited | Arts & recreation | 2021 |
| CT Kent Building Group Limited | Construction | 2016 |
| CT Property Group Ltd | Real estate | 2026 |
| CT1 Security Limited | Administrative & support | 2026 |
| CT1 Technologies Limited | Information & communication | 2025 |
| CT3 Quality, Compliance & Validation Services Limited | Information & communication | 2026 |
| CTL Car and Commercials Ltd | Wholesale & retail | 2025 |
| CTL Commercials Ltd | Wholesale & retail | 2022 |
| CTL Systems Ltd | Information & communication | 2015 |
| CTN Innovations UK Ltd | Other services | 2026 |
| Ctrlspc Ltd | Information & communication | 2019 |
| CTT Charity Payments Limited | Administrative & support | 2001 |
| Cubos Solutions Ltd | Wholesale & retail | 2024 |
| Culinary Adventures Limited | Administrative & support | 2023 |
| Culinary Ninja Creations Ltd | Manufacturing | 2026 |
| Culminare Capital Limited | Financial services | 2025 |
| Cult 94 Ltd | Information & communication | 2024 |
| Culturesmith Limited | Administrative & support | 2015 |
| Cumi Ltd | Wholesale & retail | 2008 |
| Cured & RAW Limited | Wholesale & retail | 2025 |
| Curing Shed Ltd | Manufacturing | 2020 |
| Curtis Squared Limited | Professional & scientific | 2020 |
| Curtiss Health & Performance Limited | Education | 2026 |
| Cusroe Investments Limited | Real estate | 2024 |
| Custom House (Gravesend) Limited | Construction | 2020 |
| CUT ABOVE2 Ltd | Other services | 2022 |
| Cuthbert and Maude Ltd | Arts & recreation | 2023 |
| Cvme Self Drive Hire Ltd | Administrative & support | 2016 |
| CW Watches (UK) Limited | Wholesale & retail | 2025 |
| CW Window Cleaning Ltd | Administrative & support | 2021 |
| CWS Solutions Ltd | Construction | 2024 |
| Cyanide and Method Limited | Arts & recreation | 2023 |
| Cybercast Limited | Information & communication | 2015 |
| Cyberclimb Technologies Limited | Information & communication | 2025 |
| Cyel Engineering Limited | Construction | 2024 |
| Cyel Technologies Limited | Wholesale & retail | 2024 |
| Cygnet Business Solutions Limited | Professional & scientific | 2004 |
| Cyphernity Limited | Information & communication | 2021 |
| D & Co Group Limited | Other services | 2019 |
| D Ahkye Limited | Public administration | 2018 |
| D C Maintenance Ltd | Construction | 2022 |
| D L Utilities Limited | Construction | 2008 |
| D M Maude Limited | Wholesale & retail | 2009 |
| D R C Productions Limited | Manufacturing | 2019 |
| D&A TEC Ltd | Arts & recreation | 2026 |
| D&D Asset Management Holdings Ltd | Financial services | 2024 |
| D&D Asset Management Ltd | Professional & scientific | 2017 |
| D&F Stevens & Co Ltd | Financial services | 2017 |
| D&J Country Farm Retreats Ltd | Hospitality | 2022 |
| D&K Bakery&Coffee Ltd | Wholesale & retail | 2021 |
| D.B. Project Management Ltd | Professional & scientific | 1998 |
| D.N.A. Walter Ltd | Professional & scientific | 2018 |
| D.T.S. Investments Limited | Real estate | 1972 |
| D6 Digital Ltd | Extraterritorial | 2022 |
| DA Digital Ltd | Information & communication | 2026 |
| Dacab Ltd | Transport & logistics | 2023 |
| Daddy Homes Ltd | Real estate | 2025 |
| Dagama Strakes Limited | Financial services | 2013 |
| Dakota Sussex Limited | Financial services | 2016 |
| Dalemarch Limited | Real estate | 1999 |
| Daly Trading Holdings Ltd | Wholesale & retail | 2025 |
| Dams Smiles Ltd | Health & social care | 2025 |
| DAN and Lucy Ltd | Professional & scientific | 2022 |
| Dance Academy HQ London LLP | | 2023 |
| Dance Academy HQ Ltd | Education | 2018 |
| Dane Valley Vehicle Services Limited | Wholesale & retail | 2018 |
| Danell SQL Limited | Information & communication | 2010 |
| Daniel Bayle Ltd | Arts & recreation | 2019 |
| Daniel M Delivery Ltd | Transport & logistics | 2020 |
| Daniel Tzipi Ltd | Construction | 2022 |
| Dardha Construction Ltd | Construction | 2021 |
| Dare to Tread Limited | Professional & scientific | 2025 |
| Daring Technologies Ltd | Wholesale & retail | 2025 |
| Dark Blue Professional Ltd | Professional & scientific | 2018 |
| Dark Blue Umbrella Ltd | Professional & scientific | 2015 |
| Dark Matter Partners Ltd | Administrative & support | 2023 |
| Darkhorseone Limited | Information & communication | 2023 |
| Dary Transport Ltd | Transport & logistics | 2024 |
| DAT IT Risk Services Ltd | Information & communication | 2022 |
| Data-X Technology Limited | Information & communication | 2020 |
| Datawise Technology Limited | Information & communication | 2002 |
| Dataxsphere Solutions Limited | Professional & scientific | 2025 |
| Dauntless London Ltd | Professional & scientific | 2016 |
| Davcon Investments Ltd | Financial services | 2025 |
| Dave Mannings Painting Contractors Limited | Construction | 2005 |
| Dave N CHY Ltd | Real estate | 2023 |
| David Allchurch Investments Limited | Administrative & support | 2024 |
| David Cuff Limited | Professional & scientific | 2009 |
| David Cuff Motorsport Consultant LLP | | 2025 |
| David James Roberts Consultancy Limited | Information & communication | 2019 |
| David Lilford Fine Art Ltd | Arts & recreation | 2004 |
| David Lilford Framing Limited | Professional & scientific | 2006 |