| Comfort Harmony Care Ltd | Health & social care | 2022 |
| Commito Ltd | Information & communication | 2026 |
| Concept Facilities Holdings Limited | Professional & scientific | 2015 |
| Concept Facilities Management Limited | Construction | 2000 |
| Concept Facilities Property Limited | Real estate | 2018 |
| Concept Homes Limited | Extraterritorial | 2000 |
| Concurrent Systems Incorporated Limited | Information & communication | 2001 |
| Conference Selection Limited | Administrative & support | 2001 |
| Connected Media Partners Ltd | Information & communication | 2024 |
| Connic Limited | Professional & scientific | 2014 |
| Conscious Life Limited | Information & communication | 2014 |
| Conscious Psychology Limited | Health & social care | 2012 |
| Contrillient Ltd | Other services | 2022 |
| Controlled Logistics Limited | Transport & logistics | 1996 |
| Cool Rock Holdings Ltd | Financial services | 2020 |
| Cool Rock Property Management Ltd | Households | 2026 |
| Coolpower Electrical Limited | Construction | 2018 |
| Copse Farm Ltd | Information & communication | 2013 |
| Corgi Couriers Ltd | Extraterritorial | 2025 |
| Corgi Digital Ltd | Extraterritorial | 2025 |
| Coria Limited | Information & communication | 2025 |
| Corp ACT Ltd | Professional & scientific | 2020 |
| Corporate Logistics Limited | Transport & logistics | 2013 |
| Corr (Andover) Limited | Administrative & support | 2015 |
| Corr Property Services Limited | Real estate | 2022 |
| Corr Recruitment Limited | Administrative & support | 2006 |
| Cost Saver UK Limited | Wholesale & retail | 2022 |
| Cosy Coliving Ltd | Real estate | 2020 |
| Cothelstone Consulting Ltd | Professional & scientific | 2026 |
| Cotswold Treehouses Ltd | Construction | 2022 |
| Cram Limited | Administrative & support | 2014 |
| Cranley Commodities Limited | Financial services | 1982 |
| Create Tomorrow Today Limited | Professional & scientific | 2007 |
| Create Travel Group Ltd | Administrative & support | 2026 |
| Createco Ltd | Professional & scientific | 2025 |
| Creative Content Studio Limited | Information & communication | 2024 |
| Crescella Ricci Ltd | Agriculture & fishing | 2024 |
| Crest Home Improvements (Reading) Ltd | Construction | 2005 |
| Croft Risk Management Limited | Professional & scientific | 2007 |
| Cronin Engineering Construction Ltd | Professional & scientific | 2023 |
| Cronk Advisory Ltd | Information & communication | 2026 |
| Cronos App Ltd | Information & communication | 2025 |
| Crookham Common Residents Management Company Limited | Households | 2006 |
| Crossways Pharma Limited | Professional & scientific | 2018 |
| Crossways Security Limited | Administrative & support | 2006 |
| Crown Electric Company (Newbury) Ltd | Construction | 2019 |
| Crown Imagery Ltd | Professional & scientific | 2024 |
| Crownwood Strategic Leisure Ltd | Professional & scientific | 2025 |
| Cuckoo Consulting Limited | Professional & scientific | 2012 |
| Current Connection Ltd | Construction | 2020 |
| D D Motor Trader Ltd | Wholesale & retail | 2025 |
| D G Tiling Ltd | Construction | 2007 |
| D Gilmore Property Services Limited | Construction | 2013 |
| D L T Plumbing & Heating Ltd | Construction | 2017 |
| D Van DER Spuy Limited | Health & social care | 2019 |
| D'Urberville Limited | Construction | 1998 |
| D.W.B. Property Services Ltd | Households | 2019 |
| Dagda Industries Ltd. | Wholesale & retail | 2017 |
| Daisy’S Independent Coffee Shop Ltd | Hospitality | 2025 |
| Dalal Consulting Limited | Professional & scientific | 2017 |
| Dalmann Limited | Wholesale & retail | 2013 |
| Darlington 1 Ltd | Real estate | 2025 |
| Data Minds Consulting Ltd | Professional & scientific | 2023 |
| Datajac Solutions Limited | Information & communication | 2026 |
| Datalytics Solutions Ltd | Professional & scientific | 2026 |
| David Thompson Home Improvements Limited | Construction | 2011 |
| DAZ Property Maintenance L.P. | | 2016 |
| DBD Leisure Limited | Hospitality | 2010 |
| DBD70047 Ltd | Financial services | 2026 |
| DBR Roofing & Handyman Ltd | Construction | 2022 |
| Dbrmb Ltd | Information & communication | 2017 |
| DCA Dragon Limited | Wholesale & retail | 2015 |
| Ddnmkf Limited | Financial services | 2026 |
| DE Sports Therapy Limited | Arts & recreation | 2021 |
| Dealfuel Ltd | Information & communication | 2016 |
| Dean White Marine Consultancy Limited | Manufacturing | 2003 |
| Decaf Post Production Limited | Information & communication | 2020 |
| Decidon Ltd | Information & communication | 2024 |
| Decision Comfort Limited | Information & communication | 2020 |
| Delamere Property Investments Ltd | Construction | 2025 |
| Delta Fragrance and Flavour Limited | Manufacturing | 1993 |
| Derby 1 Ltd | Real estate | 2023 |
| Derwent Apartments Limited | Real estate | 1999 |
| Derwent House Investment LLP | | 2012 |
| Designs by Sazz Limited | Wholesale & retail | 2017 |
| Detail My Car Limited | Wholesale & retail | 2015 |
| Dexter Newbury Ltd | Real estate | 2017 |
| DFM Advisory Ltd | Information & communication | 2026 |
| DHG Consultancy Services Ltd | Information & communication | 2023 |
| Dieu-Donne Health Care Ltd | Health & social care | 2019 |
| Digimedia Limited | Information & communication | 1992 |
| Diginet Marketing Ltd | Information & communication | 2010 |
| Discovery Place (Newbury) Management Company Limited | Households | 2003 |
| Disraeli Limited | Real estate | 2017 |
| Divergent Works Ltd | Information & communication | 2024 |
| Diyers Ltd | Construction | 2025 |
| DJS Commercials Ltd | Wholesale & retail | 2018 |
| DK Investments Holdings Ltd | Hospitality | 2020 |
| DMS Fabrications Ltd | Manufacturing | 2006 |
| DNA Home Improvements Ltd | Construction | 2018 |