| Country Manor Holdings (International) Limited | Professional & scientific | 1997 |
| Countryfiled Ltd | Professional & scientific | 2005 |
| County Marquees (East Anglia) Ltd | Extraterritorial | 2025 |
| Coval Limited | Administrative & support | 2021 |
| Coversure Sevenoaks Ltd | Financial services | 2020 |
| CPP Civil Engineering Limited | Financial services | 2020 |
| CPP Enterprises Limited | Financial services | 2020 |
| CPP Plant Limited | Construction | 2012 |
| Cralin Property Services Ltd | Construction | 2015 |
| Cravenwood Close Residents Management Ltd | Households | 2011 |
| CRB Plumbing and Heating Essex Ltd | Construction | 2025 |
| Creative Fabrik Limited | Professional & scientific | 2025 |
| Creative MAX Limited | Wholesale & retail | 1999 |
| Cropco Limited | Agriculture & fishing | 2004 |
| CRS Building and Property Maintenance Ltd | Administrative & support | 2020 |
| Crystal Water Plumbing and Heating Limited | Construction | 2018 |
| Cultured World Creative Limited | Administrative & support | 2015 |
| Cuppa Trading Ltd | Wholesale & retail | 2021 |
| Curry Cottage Halstead Limited | Hospitality | 2018 |
| Curry Cottage Head Street Limited | Hospitality | 2023 |
| Cursed Monkey PAW Limited | Information & communication | 2019 |
| CUT Maple Fires & Stoves Limited | Other services | 2008 |
| CWD Plant & Haulage Limited | Agriculture & fishing | 2004 |
| Cxw/Cpw Wrestling Ltd | Arts & recreation | 2025 |
| D & I London Limited | Real estate | 2023 |
| D C Denny & SON (Roofing) Limited | Construction | 2006 |
| D C Electrical Contractors Limited | Construction | 1999 |
| D G Electrical Installations (Essex) Limited | Construction | 2019 |
| D Line Markings Ltd | Construction | 2014 |
| D Mason Builders Limited | Professional & scientific | 2008 |
| D Ollivier Designs Limited | Real estate | 2017 |
| D P (UK) Limited | Arts & recreation | 1993 |
| D P Fencing Contractors Limited | Construction | 2013 |
| D S & M a Mellor Car Sales Limited | Wholesale & retail | 2005 |
| D T Service Ltd | Manufacturing | 2002 |
| D&A Lettings Group Ltd | Real estate | 2025 |
| D. Mason Developments Limited | Construction | 2005 |
| D.O.G Security Services Ltd | Administrative & support | 2010 |
| Daisy Walker Ltd | Professional & scientific | 2023 |
| Dale's the Hair Salon Limited | Other services | 2013 |
| DALGIC27 Ltd | Hospitality | 2025 |
| DAN J S Limited | Administrative & support | 2018 |
| Danial Convenience Store Limited | Wholesale & retail | 2026 |
| Daniel Gibbons Limited | Construction | 1972 |
| Dare to Aspire Ltd | Education | 2020 |
| Davenpool Ltd | Real estate | 2012 |
| David & Aaron's Ltd | Wholesale & retail | 2023 |
| Davidson Developments Limited | Extraterritorial | 2016 |
| Day's of Hedingham Limited | Wholesale & retail | 1987 |
| Dcnc Properties Limited | Real estate | 2025 |
| DCS Corporate Limited | Manufacturing | 2017 |
| Dcss Legal Services Limited | Administrative & support | 2013 |
| DE Vere Development and Construction Ltd | Construction | 2015 |
| DE Vere Transport Limited | Transport & logistics | 2016 |
| Deacon Properties (Lavenham) Limited | Extraterritorial | 2013 |
| Dean Middleton Limited | Professional & scientific | 2021 |
| Define ME Ltd | Information & communication | 2016 |
| Delivery Through Insight Limited | Professional & scientific | 2019 |
| Delmat Ltd | Professional & scientific | 2008 |
| Demanda Concepts Limited | Extraterritorial | 2024 |
| Denbigh Care Group Limited | Health & social care | 2018 |
| Derek Snell Lift Solutions Limited | Professional & scientific | 2019 |
| Design Fabrications Ltd | Manufacturing | 2023 |
| Desilt Limited | Extraterritorial | 2015 |
| Detaclip Limited | Wholesale & retail | 2006 |
| Development Project Recovery Services Limited | Real estate | 2009 |
| Diamond Cristal Valeting Centre Ltd | Administrative & support | 2023 |
| Digital Bookkeeping Ltd | Professional & scientific | 2019 |
| Digital Kelp Ltd | Information & communication | 2025 |
| Digital KIN Limited | Information & communication | 2017 |
| DIGITALMEDIA24 Limited | Professional & scientific | 2014 |
| Dimensions Trampoline Club | Arts & recreation | 2012 |
| Dixey Developments Limited | Construction | 2012 |
| DJR Electrical Limited | Construction | 2007 |
| DK & M Property Limited | Real estate | 2019 |
| DK & O Property Limited | Real estate | 2021 |
| DLB Supply Chain Limited | Professional & scientific | 2020 |
| DN Butler Limited | Professional & scientific | 2023 |
| DNJ Enterprises Ltd | Real estate | 2026 |
| DO Creative Design Consultants Limited | Professional & scientific | 2009 |
| Dohoz Ltd | Real estate | 2025 |
| Doshghor Limited | Hospitality | 2026 |
| DOTSLASH360 Solutions Ltd | Information & communication | 2024 |
| Down to the Wire Ltd | Extraterritorial | 2025 |
| DR Claire Warner Limited | Health & social care | 2018 |
| DR4X4 Limited | Manufacturing | 2012 |
| Draak Limited | Other services | 2013 |
| DRB Compliance Limited | Administrative & support | 2020 |
| Drift Nutters Ltd | Arts & recreation | 2019 |
| DS Services (Southeast) Limited | Wholesale & retail | 2014 |
| DSB Build Ltd | Construction | 2023 |
| DSB Investments Ltd | Financial services | 2026 |
| DSB Rentals Limited | Real estate | 2022 |
| DSR Commercials Ltd | Extraterritorial | 2020 |
| DT Home Services Ltd | Construction | 2026 |
| Durnbury Limited | Manufacturing | 1967 |
| E Edmunds Ltd | Administrative & support | 2022 |
| E.B.W.I. Ltd | Construction | 2004 |
| EA Vehicle Rental Limited | Administrative & support | 2012 |
| East Anglia & London Properties Limited | Construction | 1978 |