| Danny Homeware Import Ltd | Wholesale & retail | 2023 |
| Danny's Engineering Services Ltd | Construction | 2015 |
| Danush Ltd | Construction | 2024 |
| Daoud 288 Trading Ltd | Wholesale & retail | 2024 |
| DAR Carpets and Flooring Ltd | Wholesale & retail | 2018 |
| DAR Holiday Lettings Ltd | Hospitality | 2021 |
| Darap Limited | Professional & scientific | 2011 |
| Dare 2 BE Agency Ltd | Information & communication | 2024 |
| Dark Electrical Limited | Construction | 2019 |
| Dark Property Developments Ltd | Real estate | 2023 |
| Darling Investments Ltd | Construction | 2019 |
| Darren Roberts Limited | Professional & scientific | 2014 |
| Darwin Inns Limited | Hospitality | 2010 |
| DAS Electrical Services Ltd | Manufacturing | 2022 |
| Datamedica Ltd | Information & communication | 2026 |
| Datatel Networks Ltd | Information & communication | 2011 |
| Date Electronic Supplies Limited | Professional & scientific | 2014 |
| Datum Advanced Composites Limited | Extraterritorial | 2022 |
| Daughters of Asili Ltd | Wholesale & retail | 2025 |
| Dave Brunnock Decorating Ltd | Construction | 2023 |
| Dave Death Motorcycles (IW) Limited | Wholesale & retail | 2005 |
| Dave Gooding Site Services Limited | Construction | 2022 |
| Dave Sargent Windows Limited | Extraterritorial | 1987 |
| Davenport Business Solutions Ltd | Information & communication | 2025 |
| David Bragg Roofing Contractor Limited | Construction | 2022 |
| David Childs Music Limited | Wholesale & retail | 2012 |
| David Dowling Limited | Manufacturing | 1985 |
| David J Stevenson Installations Limited | Construction | 2023 |
| David Krystie Properties Ltd | Real estate | 2022 |
| David Leek Ltd | Health & social care | 2024 |
| David Lewis Plant Hire Limited | Administrative & support | 2011 |
| David Lippiatt FM Ltd | Wholesale & retail | 2023 |
| David Lippiatt Properties Ltd | Real estate | 2022 |
| David M J Owens Limited | Health & social care | 2018 |
| David Merry Ltd | Wholesale & retail | 2013 |
| David Stock & Co Limited | Financial services | 1999 |
| David Taylor Properties Ltd | Real estate | 2020 |
| David Winforth Property (UK) Limited | Real estate | 2023 |
| DAVID4XL Construction Ltd | Construction | 2023 |
| Davies & Jones Developments Ltd | Construction | 2020 |
| Davies & Jones Groundworks Ltd | Construction | 2025 |
| Davies and Jones Home Solutions Ltd | Real estate | 2025 |
| Davies Brothers (Newport) Limited | Construction | 2022 |
| Davies Contractors Group Ltd | Construction | 2023 |
| Davies Contractors Ltd | Construction | 2015 |
| Davies Kidd Ltd | Administrative & support | 2013 |
| Davies Roofing South Wales Ltd | Construction | 2025 |
| Davies White & Perry Limited | Real estate | 2017 |
| Davis Commercials (South Wales) Limited | Wholesale & retail | 2023 |
| Davis Knight Homes Limited | Real estate | 2018 |
| Davis Knight Renovations Limited | Construction | 2021 |
| Davlan Construction Limited | Construction | 1981 |
| Dawcon Limited | Construction | 2000 |
| Dawks Security Limited | Administrative & support | 2016 |
| Dawlish Property Partners Ltd | Real estate | 2015 |
| Dawn H Property Ltd | Real estate | 2026 |
| Dawn to Dusk Autos Limited | Wholesale & retail | 2008 |
| Day in Day OUT Limited | Arts & recreation | 2024 |
| Day to Day Store Import Ltd | Wholesale & retail | 2026 |
| Day's Building Services Ltd | Construction | 2005 |
| Days of Steam Ltd | Manufacturing | 2020 |
| Daytodayebay Limited | Information & communication | 2018 |
| Dazzler Grips Ltd | Information & communication | 2020 |
| DB Commercial Consulting Ltd | Professional & scientific | 2025 |
| DB Holdings (2024) Ltd | Financial services | 2024 |
| DBK Assets Ltd | Real estate | 2025 |
| DC Site Services 2020 Limited | Manufacturing | 2020 |
| DC Sound Production Ltd | Information & communication | 2019 |
| DC Williams Cardiff Limited | Manufacturing | 2016 |
| Dcam Chauffeur Services Ltd | Transport & logistics | 2013 |
| DCH Agricultural Engineering Ltd | Manufacturing | 2016 |
| DCI Electrical (Wales) Limited | Construction | 2007 |
| DCI Fire Protection Limited | Construction | 2018 |
| DCJ Investments Ltd | Real estate | 2025 |
| DCN Builders Ltd | Construction | 2019 |
| DD Electrical Holdings Limited | Financial services | 2023 |
| DD Training Limited | Professional & scientific | 2019 |
| Ddga Ltd | Construction | 2021 |
| DDJ Services Ltd | Hospitality | 2015 |
| DDP6 Ltd | Arts & recreation | 2019 |
| DDR Electrics Limited | Construction | 2006 |
| DDS Site Assessment Services Ltd. | Professional & scientific | 2016 |
| DE Emirate Pacific Limited | Public administration | 2025 |
| De-Fragmented by Design Ltd | Information & communication | 2026 |
| Deaconplastering Ltd | Administrative & support | 2025 |
| Dean & Dean Ltd | Professional & scientific | 2024 |
| Dean Lewis Ltd | Information & communication | 2024 |
| Dean Ottley Building Contractors Limited | Construction | 2005 |
| Dean Parkman Architecture Limited | Professional & scientific | 2017 |
| Dean Street Units Ltd | Real estate | 2019 |
| Deans Court (Ryde) Management Co Limited | Households | 1997 |
| DEB Mayo Properties Limited | Real estate | 2016 |
| Debbysigishealthcare Ltd | Health & social care | 2025 |
| Debi Green Spa Consultancy Limited | Professional & scientific | 2017 |
| Debrief Accounting Limited | Professional & scientific | 2024 |
| Debyanne Ltd | Health & social care | 2023 |
| Decor Panel Limited | Wholesale & retail | 1998 |
| Decorpanel KBB Limited | Manufacturing | 1997 |
| Decsta Limited | Financial services | 2021 |
| Dee'Z Pizza Ltd | Hospitality | 2025 |