| Cywatch Technologies Limited | Professional & scientific | 2025 |
| CZ Zhaoyangenn Limited | Manufacturing | 2025 |
| D & a Design Group Limited | Financial services | 2025 |
| D & T Industries Limited | Wholesale & retail | 2001 |
| D a Receivables Limited | Professional & scientific | 2013 |
| D Baker & Co Limited | Professional & scientific | 2002 |
| D Carman Bssr Limited | Construction | 2014 |
| D Church Financial Solutions Limited | Financial services | 2019 |
| D Clarke Developments Ltd | Construction | 2017 |
| D D Building Limited | Construction | 2020 |
| D Ford Construction Consultants Limited | Professional & scientific | 2018 |
| D Foster Limited | Construction | 2017 |
| D FOX Aviation Ltd | Manufacturing | 2016 |
| D Holt Electrical Services Ltd | Construction | 2013 |
| D J Baker & Sons (Electrical) Ltd | Construction | 2021 |
| D J Barratt Ltd | Agriculture & fishing | 2003 |
| D J Bradford Ltd | Administrative & support | 2014 |
| D J Cross Limited | Information & communication | 2014 |
| D J S Capital Limited | Professional & scientific | 2024 |
| D K Brown Construction Ltd | Construction | 2020 |
| D N Urban Clean Ltd | Administrative & support | 2025 |
| D Osbourne Groundworks and Scaffold Services Ltd | Construction | 2012 |
| D Purvis Carpentry & Building Limited | Construction | 2013 |
| D S Martin Electrical Services Ltd | Construction | 2014 |
| D Schofield Consulting Limited | Professional & scientific | 2009 |
| D W Brooks Conveyor Belt Services Ltd | Administrative & support | 2008 |
| D&T Holdings Ltd | Real estate | 2017 |
| D'Abo Development & Property Management Limited | Real estate | 2004 |
| D'Angelo's Limited | Professional & scientific | 2004 |
| D'Arcy Inspired Limited | Professional & scientific | 2001 |
| D-Global Commerce Co., Ltd. | Wholesale & retail | 2020 |
| D-Mont Ltd | Real estate | 2021 |
| D-Wealth Care Limited | Public administration | 2022 |
| D. & R. Hankins (Manea) Holdings Limited | Agriculture & fishing | 2018 |
| D.F.Rawlinson & Co.,Limited | Professional & scientific | 1961 |
| D.G. Advertising Sales Limited | | 1980 |
| D.Hive Joy Ltd | Wholesale & retail | 2025 |
| D.J. Everson Property Development Ltd | Construction | 2013 |
| D.J. Hale Limited | Other services | 2010 |
| D.Pan Services Ltd | Manufacturing | 2025 |
| D.R.E. Pest Control Ltd. | Administrative & support | 1999 |
| D.S.L International Trading Co., Ltd | Wholesale & retail | 2025 |
| D12 Dc-Ne Limited | Real estate | 2025 |
| D12 Developments (Real Estate) Limited | Real estate | 2025 |
| D12 Developments Ltd | Construction | 2018 |
| D12 Holdco Limited | Financial services | 2020 |
| D12 Investco Limited | Real estate | 2020 |
| D12 IOS Northfleet Limited | Real estate | 2024 |
| D12 Wyck Hill Limited | Real estate | 2021 |
| D2 Direct Limited | Wholesale & retail | 2016 |
| DA Academy Limited | Education | 2019 |
| DA Medical International Limited | Wholesale & retail | 2020 |
| DA Products Ltd | Wholesale & retail | 2020 |
| DA Vicius Consulting Ltd | Information & communication | 2025 |
| DA Vinci Laboratory Solutions UK & Ireland Limited | Professional & scientific | 2008 |
| DA Vinci Life Skills CIC | Education | 2025 |
| Dabalash UK Limited | Wholesale & retail | 2025 |
| Dabo Bio-Medical Consultancy Services Limited | Professional & scientific | 2019 |
| Dacia Ltd | Manufacturing | 2025 |
| Dack Cleaning Services Ltd | Administrative & support | 2017 |
| DAD Contract Services Ltd | Energy | 2021 |
| Daedalus Ideas Limited | Financial services | 2025 |
| Daemon Consultants Limited | Information & communication | 1991 |
| Dafcam Autos Limited | Wholesale & retail | 2024 |
| Dafi Original Ltd | Manufacturing | 2023 |
| DAG Management & Consulting Ltd | Professional & scientific | 2022 |
| Daily Store Limited | Wholesale & retail | 2017 |
| DAILYNEEDS21 Limited | Wholesale & retail | 2025 |
| Daino Ltd | Professional & scientific | 2026 |
| Dairy Product Nutrition Research Center Limited | Extraterritorial | 2021 |
| Dairy Way Management Company Limited | Households | 2020 |
| Daishar Limited | Wholesale & retail | 2024 |
| Daisy Housden Studio Ltd | Professional & scientific | 2024 |
| Daisy Management and Consultancy Limited | Health & social care | 2019 |
| Daisy’S Garden Limited | Other services | 2011 |
| DAK Aviation Services Limited | Manufacturing | 2015 |
| Dakins House RTM Company Limited | Households | 2019 |
| Dakram Materials Ltd. | Wholesale & retail | 2003 |
| Dakshin Delights Limited | Hospitality | 2025 |
| Dalaid | Other services | 1997 |
| Dalby's Limited | Wholesale & retail | 1947 |
| Dalegarth Residents Company Limited | Households | 1966 |
| Dali Services Ltd | Manufacturing | 2026 |
| Dalian Dashixing Woodworking Co., Ltd. | Manufacturing | 2025 |
| Dalian XIN Ding Yuan Trade Co., Ltd | Wholesale & retail | 2018 |
| Dallas Building Services Ltd | Construction | 2023 |
| Dalmont Consulting Ltd | Construction | 2025 |
| Dalton House Services Cambridge Ltd | Professional & scientific | 2011 |
| Dalton's Houses Ltd | Real estate | 2018 |
| Daly Property Solutions Limited | Construction | 2018 |
| Dama Court Residents Management Company Limited | Professional & scientific | 2014 |
| Dama Developments Limited | Construction | 2002 |
| Dama Healthcare Limited | Health & social care | 2024 |
| Damargo Ltd | Professional & scientific | 2020 |
| Damian Brenlla Structural Workshop Limited | Professional & scientific | 2025 |
| Damian Wear Ltd | Wholesale & retail | 2025 |
| DAN and Carol Engineering Ltd | Manufacturing | 2026 |
| DAN Bespoke Automotive Ltd | Manufacturing | 2023 |
| DAN George Limited | Real estate | 2024 |
| DAN Holdings Limited | Financial services | 2008 |