| Denge Ltd | Real estate | 2020 |
| Dening Consultants Limited | Real estate | 2020 |
| Denzilcare Limited | Extraterritorial | 1983 |
| Derryglade Ltd | Real estate | 2024 |
| Descentai Limited | Information & communication | 2023 |
| Design Flow Studio Ltd | Information & communication | 2014 |
| Deutsche Telekom (UK) Limited | Information & communication | 2000 |
| Dewan Assets Ltd | Real estate | 2022 |
| DEX123 Ltd | Wholesale & retail | 2023 |
| Deyu LI Limited | Wholesale & retail | 2026 |
| Dftc Ltd | Administrative & support | 2017 |
| DG Care & Support Services Ltd | Public administration | 2025 |
| DHD Cleaning Ltd | Administrative & support | 2021 |
| DHD Smart Tyres Ltd | Wholesale & retail | 2019 |
| Diamas Partners Limited | Wholesale & retail | 2015 |
| Dick Moll, Inc. | | 1991 |
| Digimasters Ltd | Information & communication | 2017 |
| Digital Systems Pro Ltd | Information & communication | 2025 |
| Digitechnis Limited | Information & communication | 2023 |
| Digswell Lake Society | Arts & recreation | 1987 |
| Digswell Mews Management Company Limited | Households | 1986 |
| Digswell Place Management Company Limited | Households | 1987 |
| Dijitaliks Ltd | Wholesale & retail | 2024 |
| Dines Estates Ltd | Real estate | 2025 |
| DIP Dream Team Ltd | Other services | 2013 |
| DIP Dream Team Property Ltd | Real estate | 2025 |
| Director's CUT Theatre Company Ltd. | Arts & recreation | 2015 |
| Disruptive Accounting Limited | Professional & scientific | 2024 |
| Diverted Traffic Management Limited | Other services | 2019 |
| DIY Personalisation Ltd | Wholesale & retail | 2025 |
| Djaze Ltd | Information & communication | 2025 |
| DJJ Resources Ltd | Construction | 2024 |
| DJM Consultancy Services Limited | Administrative & support | 2004 |
| DLP Construction Ltd | Construction | 2019 |
| DMB Academy Ltd | Education | 2013 |
| DMJ Carpentry & Joinery Limited | Manufacturing | 2021 |
| Dnmjl Ltd | Financial services | 2025 |
| Dobbing Digital Consultancy Ltd | Information & communication | 2022 |
| Dobbing Holding Limited | Financial services | 2025 |
| Dobbing Nurseries Limited | Health & social care | 2025 |
| Dobbing Residential Lettings Ltd | Real estate | 2022 |
| Dolphin Civil Engineering Ltd | Construction | 2014 |
| DOM Whiting Ltd | Arts & recreation | 2022 |
| Donoghue Cricklewood Limited | Construction | 2022 |
| DOT to DOT Capital Ltd | Real estate | 2022 |
| DR Alex Edwards Limited | Health & social care | 2020 |
| DR Andre Angelino Ltd | Health & social care | 2021 |
| DR Journey Limited | Education | 2022 |
| DR ROB Hughes Oncology Services Limited | Health & social care | 2017 |
| Dragonfly Heart of Gold Ltd | Manufacturing | 2026 |
| Drainworx Limited | Water & waste | 2010 |
| Drake Internet Limited | Information & communication | 2022 |
| Drapers Blinds Limited | Construction | 2016 |
| DRC Construction Services Limited | Construction | 2017 |
| DRC Roofing Limited | Construction | 2019 |
| Dreni Connect Distributors Ltd | Wholesale & retail | 2026 |
| Dreni Properties Ltd | Real estate | 2026 |
| Drewmin Services Limited | Construction | 2019 |
| Drift Outdoors Ltd | Wholesale & retail | 2022 |
| Drift Technologies Ltd | Wholesale & retail | 2023 |
| Drive & Survive UK Limited | Extraterritorial | 2005 |
| Drive 121 Limited | Transport & logistics | 2016 |
| Driveline Motor Sports Limited | Administrative & support | 2010 |
| Driveway Pro Solutions Ltd | Construction | 2024 |
| Drivingnetzero Ltd | Professional & scientific | 2022 |
| DRJ Solutions Ltd | Professional & scientific | 2019 |
| Drsa Property Ltd | Real estate | 2020 |
| Dualrole Limited | Information & communication | 1986 |
| Dugo Properties Ltd | Real estate | 2020 |
| Dumitru Mihai Ltd | Professional & scientific | 2019 |
| Duncan Print Group Limited | Manufacturing | 1996 |
| Durbin Consulting & Coaching Ltd | Professional & scientific | 2023 |
| Dwarven Treasures Ltd | Wholesale & retail | 2024 |
| DXC Consulting Ltd | Professional & scientific | 2008 |
| Dxtra Limited | Wholesale & retail | 2023 |
| Dychem Limited | Wholesale & retail | 1991 |
| Dynamic Business Leaders Limited | Administrative & support | 2019 |
| Dynamic Horizon Investments Limited | Financial services | 2024 |
| Dynamic Process Management Solutions Ltd | Information & communication | 2021 |
| Dynamo 24/7 Limited | Construction | 2014 |
| Dynamo One Ltd | Health & social care | 2019 |
| Dynasty 119 Ltd | Hospitality | 2024 |
| E.W.A Consulting Ltd | Professional & scientific | 2015 |
| EAC Installations Limited | Construction | 2024 |
| Earlbrook Developments Ltd | Construction | 2025 |
| Early Years Services Limited | Administrative & support | 2025 |
| East Finchley Smiles Limited | Health & social care | 2021 |
| East Herts Accountants Limited | Professional & scientific | 2013 |
| Eastside GAS (Welwyn) Ltd | Construction | 2016 |
| Easy Autos Repair Ltd | Wholesale & retail | 2017 |
| Easy MIX Concrete Limited | Manufacturing | 2004 |
| Easy Reach Concrete Pumping Limited | Manufacturing | 2007 |
| Easyplan Building Solutions Limited | Construction | 2010 |
| Eatlunch Limited | Hospitality | 2009 |
| Eaton UK Pension Plan Trustee Limited | Manufacturing | 2016 |
| Ebbsfleet Homes Limited | Real estate | 2024 |
| Ebgca Exclusive Business Game Changers Alliance Ltd | Professional & scientific | 2018 |
| EC Sports Physiotherapy Limited | Health & social care | 2009 |
| Ecentral Ltd | Other services | 2005 |
| ECL.TRANSPORT.24 Ltd | Transport & logistics | 2024 |