| Clark Mews Management Company Limited | Professional & scientific | 1997 |
| Clarke Building & Construction Limited | Construction | 2024 |
| Claypit Hotel Limited | Hospitality | 2025 |
| Claypit Management Limited | Real estate | 2025 |
| Clayton Country Cars Limited | Administrative & support | 2004 |
| Clean Difference (Andover) Ltd | Administrative & support | 2025 |
| Clean Difference Limited | Administrative & support | 2022 |
| Cleethorpes Coastal Retreats Ltd | Hospitality | 2021 |
| Cleracres Cattery Limited | Other services | 2013 |
| Cliffeco Limited | Arts & recreation | 1989 |
| Clock Barn Limited | Hospitality | 2013 |
| Clorley Access and Plant Hire Limited | Administrative & support | 2021 |
| Cluk Animations Limited | Professional & scientific | 2024 |
| Coates and Seely Limited | Manufacturing | 2008 |
| Coating Solutions Limited | Manufacturing | 2017 |
| Cobe Limited | Information & communication | 2016 |
| COD Father Whitchurch Ltd | Hospitality | 2025 |
| Cognition Secure Ltd | Information & communication | 2014 |
| Col's Car Boot Limited | Real estate | 2023 |
| Cold Hatton Propco Limited | Real estate | 2025 |
| Colourville Limited | Arts & recreation | 2015 |
| Comfort KIT Limited | Manufacturing | 2022 |
| Community Home Care Ltd | Health & social care | 2023 |
| Compliant Medical Devices Ltd | Professional & scientific | 2020 |
| Compotool Ltd | Transport & logistics | 2013 |
| Computer Support & Services Ltd | Information & communication | 2026 |
| Conac London Ltd | Professional & scientific | 2025 |
| Consto Limited | Professional & scientific | 2012 |
| Constructing Minds With Nature CIC | Administrative & support | 2026 |
| Contact Capital Limited | Financial services | 2020 |
| Control Services (Midlands) Ltd | Manufacturing | 2010 |
| Control Systems Maintenance Ltd. | Manufacturing | 2004 |
| Conversion Consulting Ltd | Financial services | 2023 |
| Copeaid Limited | Real estate | 1987 |
| Corefy Limited | Information & communication | 2020 |
| Cosham Electrical Limited | Other services | 2010 |
| Costsense LLP | | 2016 |
| Costsense Services Ltd | Administrative & support | 2013 |
| Costsense Utilities Ltd | Construction | 2013 |
| Coton Contractors Limited | Manufacturing | 2004 |
| Coton Estate Ltd | Hospitality | 2024 |
| Coton Park Services Ltd | Agriculture & fishing | 2020 |
| Cotswold Spa Bathing Company Limited | Other services | 2023 |
| Count on US Bookkeeping Ltd | Professional & scientific | 2016 |
| Countyloos Ltd. | Water & waste | 1987 |
| Crabmill Meadows Maintenance Ltd | Administrative & support | 2025 |
| Creative Options Ltd | Professional & scientific | 2023 |
| Creative Spaces by Design Ltd | Households | 2025 |
| Credit Security Limited | Administrative & support | 1967 |
| Credit Services Ltd | Administrative & support | 2004 |
| Creed & Shore Motorworks Limited | Manufacturing | 2017 |
| Creo Property and Maintenance Solutions Limited | Construction | 2015 |
| Creo Technology Limited | Professional & scientific | 2005 |
| Crockford Consultants Limited | Information & communication | 2010 |
| Croft Gardens (Whitchurch) Management Company Limited | Households | 2017 |
| Crolla Parkhouse Limited | Professional & scientific | 2005 |
| Cross Care Limited | Health & social care | 2019 |
| Crossland Technologies Ltd | Agriculture & fishing | 2014 |
| Crownstone Consulting Limited | Real estate | 2025 |
| Crumpet Consulting Limited | Hospitality | 2014 |
| Cultura Recruitment Limited | Administrative & support | 2019 |
| Cwmc Limited | Professional & scientific | 2003 |
| CWS Development Limited | Real estate | 2019 |
| Cyanby Ltd | Professional & scientific | 2023 |
| Cyberplus Limited | Information & communication | 2014 |
| Cyklop Needham Limited | Wholesale & retail | 2014 |
| D & L Properties (Lancashire) Limited | Construction | 2021 |
| D & M Packaging Limited | Administrative & support | 2017 |
| D a Taylor & SON Limited | Construction | 2007 |
| D Beck Fabrication Ltd | Manufacturing | 2014 |
| D Shaw Construction and Groundworks Ltd | Construction | 2025 |
| D. a. Roberts Investments Limited | Financial services | 2026 |
| D.A. Hayward & SON Limited | Construction | 2002 |
| D.A.Roberts Fuels Limited | Wholesale & retail | 1999 |
| D.A.Roberts Garage Limited | Manufacturing | 1999 |
| D.A.Roberts Haulage Limited | Extraterritorial | 1999 |
| D.C. Guppy Plumbing & Heating Limited | Construction | 2003 |
| D.I. Testing and Commissioning Ltd | Construction | 2015 |
| D.J. Huxley (Farms) Limited | Agriculture & fishing | 1987 |
| D.M.W.R. Ryder Ltd | Professional & scientific | 2012 |
| D2SJ Performance Limited | Professional & scientific | 2020 |
| Daiku Limited | Other services | 2019 |
| Dairy Spares Limited | Wholesale & retail | 1996 |
| Dakar Design Limited | Professional & scientific | 2018 |
| Dakar Limited | Professional & scientific | 2017 |
| Dakar Property Ltd | Real estate | 2021 |
| Dalus Technologies Ltd | Information & communication | 2017 |
| Data Network Computing Limited | Information & communication | 2001 |
| Davenham Propco Limited | Real estate | 2025 |
| Davey Roofing Contractors Limited | Construction | 2001 |
| David Rycroft Limited | Construction | 2011 |
| David Smith Joinery Limited | Manufacturing | 2012 |
| David V Williams Holdings Limited | Manufacturing | 2014 |
| Dead Pixel Productions Ltd | Information & communication | 2017 |
| Deals Expressed Ltd | Wholesale & retail | 2023 |
| Dear Sweet Henry Limited | Wholesale & retail | 2005 |
| Deli Central Limited | Hospitality | 2008 |
| Deluxe Property Developments Ltd | Construction | 2026 |
| Denman Project Services Limited | Real estate | 2017 |
| Denmans of Whitchurch Limited | Transport & logistics | 1965 |