| DE Gournay Limited | Wholesale & retail | 1992 |
| Decisive Devices Limited | Information & communication | 2021 |
| Declan Davey Ltd. | Administrative & support | 2019 |
| Dedey Ltd | Wholesale & retail | 2024 |
| Deep Serv West Sussex Ltd | Administrative & support | 2018 |
| Deep Water Corrosion Services (U.K.) Limited | Mining & quarrying | 1986 |
| Deeproot Ventures Limited | Administrative & support | 2005 |
| DEI + Partners Limited | Construction | 2017 |
| Deixis Consulting LLP | | 2022 |
| Deja Estates Ltd | Real estate | 2025 |
| DEK Transport Ltd | Transport & logistics | 2013 |
| Delevantetapas Limited | Hospitality | 2024 |
| Deliverlooz Ltd | Administrative & support | 2021 |
| Dell Cattery Limited | Other services | 2025 |
| Dell Quay Marine Limited | Other services | 2002 |
| Dell Quay Sailing Club Ltd | Arts & recreation | 2014 |
| Delta Cyber Security Ltd | Information & communication | 2023 |
| Deltex Medical Holdings Limited | Manufacturing | 2025 |
| Demar (Sussex) Ltd | Professional & scientific | 2005 |
| Demar Accountancy Ltd | Professional & scientific | 2000 |
| Demar Group Ltd | Professional & scientific | 2019 |
| Demar Management Ltd | Professional & scientific | 2017 |
| Dementia Wellness Ltd | Extraterritorial | 2025 |
| Denbury Properties Ltd | Real estate | 2025 |
| Dendrityca Ltd | Professional & scientific | 2020 |
| Dennoti Ltd | Information & communication | 2019 |
| Dermatology and Oncology Consulting Ltd | Health & social care | 2019 |
| DESI9.81 Ltd | Professional & scientific | 2025 |
| Design a Windows Limited | Construction | 2003 |
| Design Egalite Limited | Wholesale & retail | 1996 |
| Design Warriors Limited | Information & communication | 2006 |
| Detail Dynamics Valet & Detailing Ltd | Wholesale & retail | 2025 |
| Developing Technologies | Professional & scientific | 2002 |
| Development Archaeology Services Limited | Administrative & support | 2007 |
| Device Doctors Repairs and Support Ltd | Wholesale & retail | 2020 |
| Devon & Cornwall Roofing Ltd | Construction | 2025 |
| Dfni Properties Ltd | Real estate | 2019 |
| DFS Roofing Limited | Construction | 2016 |
| DGN Engineering Ltd | Professional & scientific | 2019 |
| DGR Energies Limited | Construction | 2023 |
| Diamond Bookkeeping Ltd | Professional & scientific | 2022 |
| Diana Burden Limited | Professional & scientific | 2011 |
| Dickenson's Quality Meats Limited | Wholesale & retail | 1982 |
| Digiclass Ltd | Information & communication | 2022 |
| Digiloom Ltd | Professional & scientific | 2025 |
| Digital Asset Management & Surveying Solutions Ltd | Other services | 2017 |
| Digital Geek Ltd | Information & communication | 2023 |
| Digital Marketing DNA Ltd | Professional & scientific | 2015 |
| Digital Playmakers Ltd | Professional & scientific | 2019 |
| Digital Prospects 360 Limited | Administrative & support | 2007 |
| Digital Quest Limited | Arts & recreation | 2002 |
| Digital Republic Agency Limited | Information & communication | 2011 |
| Digital Republic Group Ltd | Information & communication | 2021 |
| Digital Team on Demand Ltd | Professional & scientific | 2016 |
| Digitally Dynamic Ltd | Information & communication | 2023 |
| Dignity Group Limited | Health & social care | 1997 |
| Dikulis Ltd | Wholesale & retail | 2026 |
| Diment Vera Holdings Limited | Real estate | 2024 |
| Dinamiks Limited | Information & communication | 2010 |
| Dings 'N' Dents Limited | Administrative & support | 2002 |
| Dinkys Sweets & Treats Ltd | Wholesale & retail | 2022 |
| Discontinuous Ltd | Wholesale & retail | 2022 |
| Discount Storage Limited | Real estate | 2025 |
| Discovery House | Other services | 2021 |
| Discript Limited | Information & communication | 1989 |
| Ditchburn Properties Limited | Real estate | 2024 |
| Diteven Advisory Limited | Professional & scientific | 2024 |
| Dixits Ltd | Health & social care | 2010 |
| Dixon Associates Ltd | Administrative & support | 2017 |
| Dj's Bars Limited | Hospitality | 2001 |
| Djam Rigs Ltd | Professional & scientific | 2020 |
| DJB Commercial Management Limited | Professional & scientific | 2024 |
| DJB Mortgage Solutions Ltd | Financial services | 2019 |
| DJC Build Group Limited | Construction | 2026 |
| DJC Housing Consultants Limited | Professional & scientific | 2010 |
| DL Brooks Ltd | Construction | 2024 |
| DLC Systems Ltd | Professional & scientific | 2016 |
| DLG Composites Ltd | Manufacturing | 2024 |
| DLL Services Ltd | Administrative & support | 2023 |
| DM Brow Bar Ltd | Other services | 2020 |
| DM Pipe Solutions Ltd | Construction | 2022 |
| DMB Composites Ltd | Manufacturing | 2023 |
| DND Consultancy Limited | Financial services | 2011 |
| DND Records Limited | Manufacturing | 2024 |
| Doctor Bird RUM Ltd | Manufacturing | 2017 |
| Dog Dotty Doggy Daycare and Boarding Ltd | Other services | 2025 |
| Dogan Handyman Services Limited | Other services | 2021 |
| Dolphin Mews Residents Company Limited | Households | 1986 |
| DOM Chester Sound Ltd | Arts & recreation | 2018 |
| Domeflow Limited | Hospitality | 1999 |
| Dometic UK Blind Systems Ltd | Manufacturing | 1990 |
| Domusea Northfields Limited | Construction | 2024 |
| DON Voyage Mobile Valeting Ltd | Administrative & support | 2025 |
| Donkomi Limited | Health & social care | 2024 |
| Donna Ockenden Limited | Health & social care | 2013 |
| Donna Ockenden Property Limited | Real estate | 2020 |
| Donnington House Care Home Limited | Health & social care | 2003 |
| Donnington Laboratories Limited | Professional & scientific | 2000 |
| Donovan Flooring Limited | Construction | 2025 |
| Doubleton Farm Cottages Limited | Hospitality | 1997 |