| CH Tech Solutions Limited | Information & communication | 2025 |
| Challenger Food & Safety Ltd | Professional & scientific | 2018 |
| Chalvingtons Sussex Ltd | Wholesale & retail | 2014 |
| Chapel at Barn Cottage Ltd | Hospitality | 2017 |
| Chariot Schemes Limited | Financial services | 2012 |
| Chasecroft Limited | Hospitality | 2013 |
| Cherished Glass Limited | Construction | 2021 |
| Chinchilla SKI Ltd | Manufacturing | 2025 |
| Citystar Limited | Professional & scientific | 2000 |
| CJ Gray Plant Hire Limited | Construction | 2003 |
| CK Asset Analytics Limited | Real estate | 2024 |
| Classic Modern Sports Limited | Wholesale & retail | 2009 |
| Classic Retrofit Limited | Wholesale & retail | 2015 |
| Clear Consultancy Ltd | Professional & scientific | 1997 |
| Clearly Cloudy Limited | Information & communication | 2015 |
| Clearwater Property Services Limited | Construction | 2023 |
| Clive Irwin Electrical Ltd | Construction | 2021 |
| Cloverfield Limited | Information & communication | 2015 |
| CMC Hope Building Ltd | Construction | 2018 |
| CMM Limited | Financial services | 2005 |
| Cocolino Shine Ltd | Wholesale & retail | 2020 |
| Cognitio Consultancy Ltd | Professional & scientific | 2026 |
| Coldharbour Services Limited | Professional & scientific | 2025 |
| Commerce House Freeholders Limited | Households | 2024 |
| Compact Cutting Contractors Ltd | Administrative & support | 2017 |
| Compost Club Ltd | Water & waste | 2021 |
| Context Editions Limited | Information & communication | 2020 |
| Contron Limited | Professional & scientific | 2000 |
| Convert Property Investments Limited | Real estate | 1958 |
| Copla Ltd | Information & communication | 2004 |
| Copseland Ltd | Agriculture & fishing | 2017 |
| Corjon Properties Ltd | Real estate | 2003 |
| Coronatech Studios Limited | Information & communication | 2005 |
| Cosmos Electrical Services Limited | Construction | 2001 |
| Cottage Joinery Limited | Manufacturing | 2000 |
| Country & Town Property Management Limited | Construction | 1994 |
| County the Home Improvers Limited | Extraterritorial | 2022 |
| County Windows (Heathfield) Limited | Construction | 2010 |
| Coxdown Construction Ltd | Construction | 2010 |
| CPB Consultancy Limited | Professional & scientific | 2015 |
| CR Secure Limited | Administrative & support | 2025 |
| CR1CH1 Ltd | Transport & logistics | 2023 |
| Cream Roll Ltd | Hospitality | 2019 |
| Creative Preservation Ltd | Construction | 2012 |
| Creative Tailored Therapy Ltd | Health & social care | 2020 |
| Crimson Advisory LLP | | 2021 |
| Croftstead Ltd | Agriculture & fishing | 2025 |
| Crossan Creative Ltd | Professional & scientific | 2025 |
| Crouch Farm (Sussex) Limited | Agriculture & fishing | 2014 |
| Crowborough Accident Repair Services Limited | Wholesale & retail | 2002 |
| Crown Yard Business Services Ltd | Wholesale & retail | 2022 |
| Crowndeed UK Ltd | Wholesale & retail | 2008 |
| Croxton Building Ltd | Construction | 2021 |
| CS Home Solutions Ltd | Construction | 2024 |
| CSK Ventures Ltd | Construction | 2025 |
| Cuckmere Consulting Ltd | Other services | 2008 |
| Cuckmere Training Limited | Education | 2017 |
| Cuculo Heathfield Ltd | Wholesale & retail | 2022 |
| Cumberland (VC) Ltd | Hospitality | 2019 |
| Curstan Systems Ltd | Information & communication | 2016 |
| Curved Space Design Limited | Administrative & support | 2020 |
| Custom Carpet Cleaning Ltd | Administrative & support | 2020 |
| CWH Holdings Ltd | Administrative & support | 2025 |
| Cycle Revival Ltd | Wholesale & retail | 2021 |
| Cycling COW Ltd | Real estate | 2020 |
| Cyth Limited | Professional & scientific | 2010 |
| D H Robinson Limited | Professional & scientific | 2003 |
| D Izzard General Building Ltd | Construction | 2018 |
| D M & C ASH Limited | Construction | 1993 |
| D Stevens Utility Arboriculture Ltd | Administrative & support | 2021 |
| D. Ellis Plumbing & Heating Ltd | Construction | 2017 |
| D.C. Engineering UK Limited | Information & communication | 2007 |
| D.D.E Services Ltd | Energy | 2005 |
| Dadelon SA Ltd | Professional & scientific | 2014 |
| Daedal Designs Limited | Manufacturing | 2003 |
| DAISY2017 Limited | Agriculture & fishing | 2017 |
| Dallington Forest Development Ltd. | Agriculture & fishing | 2014 |
| Danebury Management Limited | Professional & scientific | 1999 |
| Danecroft Developments Ltd | Construction | 2016 |
| Dark Water Gallery Limited | Wholesale & retail | 2015 |
| DAS Hand Car Wash Ltd | Wholesale & retail | 2025 |
| Dave of ALL Trades Ltd | Construction | 2020 |
| David Blower Garage Door Solutions Ltd | Manufacturing | 2021 |
| David Cordon Limited | Information & communication | 2024 |
| David Mahani Limited | Health & social care | 2014 |
| David Read Creative Limited | Professional & scientific | 2011 |
| Davies Plastering Services Ltd | Construction | 2023 |
| Davigdor House LLP | | 2022 |
| Dayan Hand Car Wash Limited | Other services | 2026 |
| DBL Developments (S.E) Ltd | Construction | 2022 |
| DC Timber Framed Buildings Limited | Extraterritorial | 1998 |
| DC Timber Products Limited | Construction | 1996 |
| DDL Capital Limited | Professional & scientific | 2008 |
| Dead Lucky Ltd | Professional & scientific | 2019 |
| Delhi Spice Cottage Ltd | Hospitality | 2017 |
| Deus Eris Ltd | Information & communication | 2022 |
| Devon Healthcare Solutions Ltd | Health & social care | 2020 |
| Diamond Fibres Limited | Manufacturing | 1988 |
| Diamond Focus UK Limited | Professional & scientific | 2001 |
| Diamond Harbour Media Limited | Health & social care | 2012 |