| COR Echo Ltd | Professional & scientific | 2025 |
| Cotton Accounting Limited | Professional & scientific | 2020 |
| Country Firewood Ltd | Agriculture & fishing | 2018 |
| Countryside Home & Garden Limited | Construction | 2012 |
| Countryside Trees Limited | Agriculture & fishing | 2019 |
| Cove Naturals Ltd | Manufacturing | 2021 |
| Cpez Limited | Professional & scientific | 2024 |
| Crave Natural Limited | Hospitality | 2025 |
| Crave Outdoors Ltd | Other services | 2025 |
| Cread Media Limited | Professional & scientific | 2004 |
| Creating Caring Connections CIC | Health & social care | 2022 |
| CREATIVITY.EST25 Ltd | Wholesale & retail | 2025 |
| CRN Training Limited | Extraterritorial | 2012 |
| Crockatt Garage Limited | Wholesale & retail | 2011 |
| Cronin Inspection Services Ltd | Mining & quarrying | 2020 |
| Crown Street 1961 Limited | Extraterritorial | 2014 |
| Crystalla Spring Water Ltd | Manufacturing | 2026 |
| Csif Limited | Professional & scientific | 2007 |
| Cunningham Holdings Limited | Real estate | 2018 |
| Cunningham Owlstone LLP | | 2018 |
| Curve Property Development Limited | Construction | 2020 |
| CUSTOMER100 Ltd | Professional & scientific | 2023 |
| Cutsafe Clothing Ltd | Wholesale & retail | 2011 |
| D & T Powell Ltd | Transport & logistics | 2019 |
| D a Shave Carpentry & Joinery Limited | Construction | 2013 |
| D B Electrical and Security Limited | Construction | 2013 |
| D Baitan Ltd | Construction | 2019 |
| D S Client Account Ltd | Information & communication | 2026 |
| D Williams Services Limited | Agriculture & fishing | 2018 |
| D&M Logistics Group Limited | Financial services | 2025 |
| D&R Macrae Ltd | Financial services | 2017 |
| D. Brett Associates Limited | Administrative & support | 2003 |
| D.I.Alston Limited | Agriculture & fishing | 1955 |
| D.K. Appliances Limited | Other services | 2009 |
| DA Vinci Direct Relationships Limited | Administrative & support | 1997 |
| Daddology Limited | Professional & scientific | 2011 |
| Dafarish Kitchen Ltd | Manufacturing | 2025 |
| Damian Goddard Lighting Limited | Arts & recreation | 2008 |
| Damson House Recruitment Ltd | Administrative & support | 2025 |
| Darren Davey Traditional Building Limited | Construction | 2013 |
| Darwin Consulting (HR) Ltd | Professional & scientific | 2012 |
| Dave Hannah Home and Garden Ltd | Construction | 2019 |
| Davey Limited | Real estate | 2003 |
| David 2 Goliath Limited | Professional & scientific | 2024 |
| David Black & SON Limited | Agriculture & fishing | 1956 |
| David Evans Distribution Limited | Other services | 2023 |
| David Porter Media Limited | Wholesale & retail | 2011 |
| Davies and Macpherson Ltd | Health & social care | 2012 |
| DCE Commercial Services Limited | Transport & logistics | 2020 |
| DCM Change Management Ltd | Professional & scientific | 2025 |
| Dczm Property Holdings Ltd | Real estate | 2021 |
| Deben Homes Limited | Construction | 1998 |
| Debenham Community Centre Limited | Arts & recreation | 1991 |
| Debenham Garage Limited | Wholesale & retail | 2014 |
| Debenham Village Hall and Playing Field Trust | Arts & recreation | 2003 |
| Debtoy Limited | Extraterritorial | 2013 |
| Decor and Decorum Events Limited Liability Partnership | | 2023 |
| Deep Blue Biotech Limited | Professional & scientific | 2023 |
| DEF Construction Services Limited | Construction | 2025 |
| Delfino Pescara 1936 Finance PLC | Financial services | 2018 |
| Demat Limited | Professional & scientific | 2020 |
| Deniss Construction Ltd | Construction | 2021 |
| Dent Press Limited | Wholesale & retail | 2006 |
| Dent Worx Limited | Wholesale & retail | 2006 |
| Dentrix Limited | Wholesale & retail | 2022 |
| Denvi Contractors Ltd | Construction | 2019 |
| Depiqd Limited | Information & communication | 2016 |
| Design Floor Systems Limited | Construction | 2007 |
| Desirable Travel Ltd | Administrative & support | 2025 |
| Desire Wealth Management Limited | Professional & scientific | 2014 |
| Deskspan Limited | Information & communication | 2008 |
| Devereux Consultancy Limited | Professional & scientific | 2025 |
| DG Hospitality Limited | Hospitality | 2026 |
| Dgas Media Ltd | Professional & scientific | 2021 |
| DGF Groundworks Limited | Construction | 2017 |
| Diaper Poultry Limited | Manufacturing | 2008 |
| Dino Heating Ltd | Construction | 2026 |
| Diogenes Consulting Limited | Professional & scientific | 2004 |
| Directree Ltd | Professional & scientific | 2018 |
| Disco LEG Climbing Ltd | Manufacturing | 2014 |
| Disruptive Systems Limited | Manufacturing | 2023 |
| DJ Agri Services Limited | Professional & scientific | 2024 |
| Djelo Limited | Construction | 2013 |
| Djtl Consultancy Ltd | Professional & scientific | 2024 |
| DLC Electrical Contractors Ltd | Construction | 2018 |
| DM Paper & Packaging Products Ltd | Wholesale & retail | 2015 |
| Dmhc Properties Limited | Real estate | 2020 |
| DMN Contracts Limited | Professional & scientific | 2016 |
| DNA Mobiles & Computers Ltd | Wholesale & retail | 2021 |
| Dncaf Limited | Real estate | 2016 |
| Doss Developments & Design Ltd | Real estate | 2025 |
| Dote Transport Ltd | Transport & logistics | 2024 |
| Dotly Services Ltd | Other services | 2018 |
| Dove Stream Plumbing and Heating Ltd | Construction | 2020 |
| DPC Plumbing & Heating Ltd | Construction | 2014 |
| DPW Construction Limited | Construction | 2008 |
| DR Adam Farmer Limited | Health & social care | 2019 |
| DR R J Lloyd Limited | Health & social care | 2019 |
| Dragoman (Holdings) Limited | Financial services | 1995 |
| Dragoman Travel Limited | Construction | 2007 |