| Ducers Ltd | Professional & scientific | 2012 |
| Duchess & Bloom Ltd | Manufacturing | 2025 |
| Duchy Court Management (Harrogate) Limited | Households | 1977 |
| Duchy Homes (ANO2) Limited | Construction | 2025 |
| Duchy Homes (ANO3) Limited | Construction | 2026 |
| Duchy Homes (Bowgreave) Limited | Construction | 2019 |
| Duchy Homes (Chapelgarth) Limited | Construction | 2020 |
| Duchy Homes (Elwick) Limited | Construction | 2018 |
| Duchy Homes (Green Lane) Limited | Construction | 2022 |
| Duchy Homes (Holdings) Limited | Financial services | 2017 |
| Duchy Homes (Hoyland North) Limited | Construction | 2022 |
| Duchy Homes (Humshaugh) Limited | Real estate | 2016 |
| Duchy Homes (Micklefield) Limited | Construction | 2020 |
| Duchy Homes (Morley) Limited | Construction | 2025 |
| Duchy Homes (Nmgc) Limited | Construction | 2025 |
| Duchy Homes (North Cave) Limited | Construction | 2019 |
| Duchy Homes (Willerby) Limited | Construction | 2022 |
| Duchy Homes (Winterley 2) Limited | Construction | 2022 |
| Duchy Homes (Winterley) Limited | Construction | 2019 |
| Duchy Homes (Wynyard) Limited | Construction | 2023 |
| Duchy Homes Limited | Construction | 2011 |
| Duchy Park Mews Management Co. Limited | Households | 1986 |
| Duck Ltd | Arts & recreation | 2024 |
| Duck Soup Films Limited | Information & communication | 2014 |
| Duckers Furniture Limited | Water & waste | 1961 |
| Ducklings Childcare Limited | Health & social care | 2015 |
| Duct-Tech Solutions (UK) Ltd | Manufacturing | 2011 |
| Ductwork Solutions (Leeds) Limited | Construction | 2008 |
| Dudaan Ltd | Arts & recreation | 2021 |
| Dudecorp Ltd | Real estate | 2026 |
| Dudley Bower Group PLC | Professional & scientific | 1956 |
| Dudley Summit PLC | Administrative & support | 2001 |
| Dudleys Consulting Engineers Ltd | Professional & scientific | 2009 |
| Dudson Consultancy Limited | Information & communication | 2014 |
| DUE Mare Ltd | Hospitality | 2026 |
| DUE North Property Management Limited | Administrative & support | 2010 |
| Duffdefiance Limited | Wholesale & retail | 2003 |
| Duffy Homes Ltd | Real estate | 2023 |
| Duffys Barbershop Ltd | Other services | 2021 |
| Dufton Plumbing & Heating Supplies Limited | Wholesale & retail | 1986 |
| DUI Ltd | Transport & logistics | 2025 |
| Duissern Grundbesitz Ltd | Construction | 2012 |
| Dukahn Limited | Real estate | 2024 |
| Duke Studios Limited | Professional & scientific | 2015 |
| Dukevale Limited | Extraterritorial | 1995 |
| Duko Properties Limited | Real estate | 2017 |
| Dulit Ltd | Wholesale & retail | 2026 |
| Dullingham Park Limited | Agriculture & fishing | 2022 |
| Dumbledore Limited | Wholesale & retail | 2021 |
| Dumcrieff Ltd | Households | 2025 |
| Dume Group Ltd | Construction | 2021 |
| Dumilie Services Limited | Health & social care | 2016 |
| Duminy Consulting Ltd | Information & communication | 2013 |
| Dumouchel Limited | Wholesale & retail | 2002 |
| DUN Lane Limited | Households | 2013 |
| Dunamax Fitness UK Ltd | Information & communication | 2022 |
| Dunarea Limited | Wholesale & retail | 2022 |
| Dunarea MED Ltd | Wholesale & retail | 2021 |
| Duncan Market Ltd | Wholesale & retail | 2025 |
| Duncan Maxwell-Stewart Ltd | Professional & scientific | 2015 |
| Duncan Mini Market Limited | Wholesale & retail | 2025 |
| Dundee Holdco 3 Limited | Administrative & support | 2005 |
| Dundee Holdco 4 Limited | Administrative & support | 2005 |
| Dundee Pikco Limited | Administrative & support | 2007 |
| Dundonald (Cumbernauld) Limited | Real estate | 2006 |
| Dundonald Property Investments Limited | Real estate | 1998 |
| Dune Developments Limited | Real estate | 2003 |
| Dune Financial Holdings Limited | Financial services | 2017 |
| Dune Financial Planning Limited | Financial services | 2012 |
| Dunelm Pharma Limited | Health & social care | 2009 |
| Dunford House Fish Farm Ltd | Agriculture & fishing | 2025 |
| Dungle Ltd | Information & communication | 2019 |
| Dunkeswick Farm Developments LLP | | 2026 |
| Dunkeswick Farm Ventures Limited | Real estate | 2025 |
| Dunkeswick Homes (Investments) Limited | Real estate | 2024 |
| Dunkeswick Homes Limited | Extraterritorial | 2004 |
| Dunleavy Medical Limited | Health & social care | 2021 |
| Dunmore Holdings Limited | Financial services | 2018 |
| Dunmore Properties Ltd | Households | 2022 |
| Dunne Consulting Associates Ltd | Information & communication | 2023 |
| Dunne Defence Systems Limited | Professional & scientific | 2013 |
| Dunning & Fairbank Limited | Manufacturing | 1978 |
| Dunning Plant Hire Limited | Administrative & support | 2023 |
| Dunnington Enterprises Limited | Hospitality | 2017 |
| Dunnock Developments Limited | Construction | 2020 |
| Dunnock Homes Limited | Construction | 2020 |
| Dunnock Investments Limited | Financial services | 2020 |
| Dunnock Properties Limited | Construction | 2020 |
| Dunnrite Construction and Plant Ltd | Construction | 2025 |
| Dunnrite Properties Ltd | Real estate | 2023 |
| Dunnrite Protection Dogs Ltd | Administrative & support | 2024 |
| Dunnrite Roofing Ltd | Construction | 2024 |
| Dunnrite Scaffolding Ltd | Construction | 2021 |
| Dunorlan Freehold Association Limited | Households | 2014 |
| Dunraven Street Mayfair Limited | Real estate | 2022 |
| Dunsforth Court Management Company Ltd | Real estate | 2026 |
| Dunstall Holdings Limited | Professional & scientific | 2010 |
| Dunston Enterprise Limited | Health & social care | 2015 |
| Dunya Enterprise Ltd | Wholesale & retail | 2024 |
| DUO Dine Ltd | Hospitality | 2025 |