| Cyber Tech Squad Limited | Information & communication | 2023 |
| Cyberspark Limited | Professional & scientific | 2000 |
| Cyberzenithlab Limited | Information & communication | 2025 |
| Cycloploid Ltd | Wholesale & retail | 2025 |
| Cygnet Ceilings Limited | Construction | 2004 |
| Cygnet Court (Bishop's Stortford) Management Company Limited | Real estate | 1993 |
| Cyril MAE Trader Ltd | Wholesale & retail | 2026 |
| D & a Health & Pet Foods Limited | Wholesale & retail | 2003 |
| D & D Decor (UK) Ltd | Construction | 2006 |
| D & E Landscapes Ltd | Administrative & support | 2001 |
| D & P Scaffolding Limited | Construction | 1999 |
| D & P Smith Fencing Limited | Wholesale & retail | 2006 |
| D & S Electrical Limited | Construction | 1999 |
| D a & SON Ltd | Real estate | 2006 |
| D and G Electrical Contractors Limited | Construction | 2000 |
| D and T Haulage Limited | Information & communication | 2005 |
| D B Whiting Limited | Construction | 2002 |
| D Barker Interiors Limited | Construction | 2006 |
| D Biggs Joinery Ltd | Manufacturing | 2015 |
| D Cannon Limited | Construction | 1997 |
| D G Publishing Limited | Information & communication | 2003 |
| D G Residential Developments Limited | Construction | 2004 |
| D J Baker & SON Limited | Wholesale & retail | 2003 |
| D J Selfe Transport Limited | | 1994 |
| D Jones Electrical Limited | Construction | 2007 |
| D R Baker Financial Services Ltd | Financial services | 2006 |
| D Shoe Repair Limited | Other services | 2007 |
| D T Trucks Limited | Wholesale & retail | 2006 |
| D W Squier Limited | Agriculture & fishing | 2014 |
| D Zambelis Holdings Ltd | Financial services | 2018 |
| D Zambelis Ltd | Wholesale & retail | 2015 |
| D Zambelis Stone Machinery Ltd | Wholesale & retail | 2011 |
| D&D Rail (UK) Limited | Construction | 2006 |
| D&R Accounting Services Limited | Professional & scientific | 2003 |
| D'Cruz & White Limited | Professional & scientific | 1999 |
| D'Vine Limited | Wholesale & retail | 2010 |
| D. B. M. Chemicals Limited | Wholesale & retail | 1975 |
| D. Barham Limited | Health & social care | 2005 |
| D. Essex Freight Services Limited | | 1975 |
| D. Hampton & Co. Limited | Professional & scientific | 2000 |
| D. Johnson and Sons Limited | Wholesale & retail | 1961 |
| D. Kirby (Metal Merchants) Limited | Administrative & support | 1992 |
| D. Salmon Cars Limited | Wholesale & retail | 1969 |
| D.C.A. Properties Limited | Real estate | 2004 |
| D.C.G. Panel Products Ltd. | Wholesale & retail | 1997 |
| D.F. MAY Roofing Limited | Construction | 2005 |
| D.G. Farran Consultants Limited | Information & communication | 1997 |
| D.G. Supplyline Limited | Wholesale & retail | 2000 |
| D.G. White & Co. (Builders) Limited | | 1972 |
| D.H. Saunders Property Limited | Real estate | 1973 |
| D.J. Higgins Building Works Limited | Construction | 1978 |
| D.J. Higgins Construction Limited | Construction | 1978 |
| D.J. Higgins Investments Limited | Real estate | 1980 |
| D.M. Property Services Limited | Real estate | 2003 |
| D.R Barnes & Sons Ltd | Construction | 2000 |
| D.R.M. Investments Limited | Real estate | 2006 |
| D.Salmon Garages Limited | Professional & scientific | 1986 |
| D.T. Mathews & Co. (Coggeshall) Limited | Wholesale & retail | 1974 |
| D4K Estate Limited | Real estate | 2016 |
| Dacia Ecohealth Ltd | Health & social care | 2013 |
| Dada Investments Limited | Real estate | 2002 |
| Daddata Limited | Health & social care | 2005 |
| Dadini Icecream Limited | Extraterritorial | 2008 |
| Dadu Ice Cream Ltd | Wholesale & retail | 2005 |
| Dagenham Gospel Trust | Professional & scientific | 2003 |
| Dagenham Green Phase 1 Commercial Ltd | Real estate | 2026 |
| Dagenham Properties Ltd | Real estate | 2006 |
| Dahnay Logistics (UK) Ltd | Transport & logistics | 2021 |
| Dairylicious Wholesalers Ltd | Wholesale & retail | 2023 |
| Daisy’S Burgers BR Ltd | Hospitality | 2025 |
| Dalau Limited | Manufacturing | 1958 |
| Dallas & Noble Limited | | 1988 |
| Daltruism Limited | Health & social care | 2007 |
| Damark Electrical Limited | Wholesale & retail | 2006 |
| Damstead Park Management Company Limited | Households | 2015 |
| Damton Limited | Agriculture & fishing | 1996 |
| Damus Workshop (1983) Limited | | 1983 |
| DAN Consultants Limited | Information & communication | 1993 |
| Danasim Ltd | Wholesale & retail | 2025 |
| Danbury Plaster Mouldings Ltd | Construction | 2000 |
| Dander Appliance Services Limited | Wholesale & retail | 1964 |
| Dandy Paws Ltd | Wholesale & retail | 2025 |
| Dandy Rose Limited | Hospitality | 2025 |
| Danea UK Limited | Professional & scientific | 2007 |
| Danframpton.Com Limited | Information & communication | 2010 |
| Danica Services Limited | | 1982 |
| Daniel Bean Holdings Limited | Professional & scientific | 2024 |
| Danimac Limited | Wholesale & retail | 1999 |
| Dannells Limited | Wholesale & retail | 2018 |
| Danny Aarons Capital Management Ltd | Real estate | 2026 |
| Danzer UK Limited | Wholesale & retail | 1978 |
| Dapple Steed Limited | Agriculture & fishing | 2005 |
| Dappled Light Limited | Information & communication | 2021 |
| Dara Healthcare Solutions Limited | Health & social care | 2026 |
| Darkarpavin Ltd | Professional & scientific | 2025 |
| Darley Global Limited | Agriculture & fishing | 2025 |
| Dart Design Ltd | Professional & scientific | 2005 |
| Dartpack Limited | | 1986 |
| Darvy Properties Ltd | Real estate | 2014 |
| DAS Works Ltd | Professional & scientific | 1998 |