| Desifa Ltd | Information & communication | 2018 |
| Design 365 Solutions Limited | Information & communication | 2011 |
| Design Visualisation Limited | Professional & scientific | 2003 |
| DESIGN4 Ltd | Construction | 2019 |
| Designed by Nature Ltd | Extraterritorial | 2024 |
| Designs 4 Less Limited | Administrative & support | 2018 |
| Destination X Marketing Ltd | Professional & scientific | 2025 |
| Destiny Consulting Limited | Real estate | 2008 |
| Dev's Auto Logistics Ltd | Transport & logistics | 2025 |
| Devilish Detailing Ltd | Wholesale & retail | 2025 |
| Devine Publishing Services Ltd | Information & communication | 2009 |
| Devonport Hospitality Limited | Hospitality | 2018 |
| Deyvora Limited | Wholesale & retail | 2026 |
| DFL Materials Handling Limited | Manufacturing | 1994 |
| DFM Consulting UK Limited | Information & communication | 2009 |
| DG Builders (MK) Ltd | Construction | 2021 |
| Dgap UK Limited | Wholesale & retail | 2016 |
| DGB Building Services Limited | Construction | 2016 |
| DGS Futures Ltd | Real estate | 2024 |
| DH Electrical & Mechanical Ltd | Construction | 2017 |
| Dhilpe House Ltd | Real estate | 2024 |
| DHM Roofing and Building Specialists Ltd | Construction | 2023 |
| Diaden Limited | Information & communication | 2011 |
| Diagnose & FIX (NE) Ltd | Manufacturing | 2016 |
| Diagram Learning Studio Ltd | Information & communication | 2026 |
| Diamond 4X4 Repairs Limited | Wholesale & retail | 2010 |
| Diamond Emerald Holdings Ltd | Financial services | 2025 |
| Diamond Restaurant Limited | Hospitality | 2021 |
| Diamondcarsalescompany Limited | Wholesale & retail | 2024 |
| Diamonds Group Limited | Wholesale & retail | 2025 |
| Dianne Jefferies Hairdressing Ltd | Other services | 2019 |
| Dick Lawson County Durham Limited | Real estate | 2014 |
| Dickinson Media Limited | Other services | 2007 |
| Diecast Models Direct Ltd | Wholesale & retail | 2016 |
| Diffract Design Ltd | Professional & scientific | 2023 |
| Digital Evidence Virtual Centre of Excellence C.I.C. | Professional & scientific | 2015 |
| Digital Extra Limited | Information & communication | 2019 |
| Digital Innovations Ltd | Professional & scientific | 2009 |
| Digital Office Solutions (Tyne and Wear) Ltd | Manufacturing | 2005 |
| Digital Office Solutions Limited | Manufacturing | 1998 |
| Digital Publishing Agora Ltd | Information & communication | 2022 |
| Digitalpaintwin Ltd | Information & communication | 2026 |
| Dima (NA) Market Ltd | Wholesale & retail | 2025 |
| Dingers Hollow Farm Ltd | Extraterritorial | 2013 |
| Dinsdale Control Ltd | Professional & scientific | 2023 |
| Dinsdale Farming Limited | Agriculture & fishing | 2012 |
| Dinsdale Hall & Park Freehold & Management Company Ltd | Households | 2023 |
| Dinsdale Spa (Management) Limited | Households | 1983 |
| Dinsdale Technical Services Limited | Professional & scientific | 2016 |
| Diony Investigation Security Events Ltd | Administrative & support | 2015 |
| Direct Agile Ltd | Information & communication | 2013 |
| Direct Agility Limited | Extraterritorial | 2023 |
| Direct Catering Ltd | Hospitality | 2022 |
| Direct Flooring (North East) Ltd | Wholesale & retail | 2026 |
| Direct Signs (Northern) Limited | Manufacturing | 1990 |
| Direct Villas UK Limited | Professional & scientific | 2006 |
| Directsolo Ltd | Information & communication | 2026 |
| Dirtbusters Laundry Services Ltd | Other services | 2024 |
| Discerning Digital Limited | Information & communication | 2012 |
| Dishabille Ltd | Wholesale & retail | 2018 |
| Ditto CC Ltd | Wholesale & retail | 2024 |
| Divergent Roadman Digital Ltd | Information & communication | 2020 |
| Divergent Roadman Ltd | Other services | 2019 |
| Divine Digital Limited | Administrative & support | 2025 |
| Diyana 1 Store Ltd | Wholesale & retail | 2025 |
| DJ Autocare and Tuning Ltd | Wholesale & retail | 2022 |
| DJF Fibre Ltd | Information & communication | 2023 |
| DJG Care Services Ltd | Health & social care | 2021 |
| DJL Networks Contracting Limited | Professional & scientific | 2015 |
| DJL Renovations Ltd | Construction | 2021 |
| Djpb Limited | Manufacturing | 2019 |
| DJS Weld Limited | Manufacturing | 2016 |
| DJW Talent Ltd | Administrative & support | 2017 |
| DK Couriers Ltd | Transport & logistics | 2020 |
| DK Gell Construction Limited | Construction | 2012 |
| DK Security Services (Darlington) Limited | Administrative & support | 2012 |
| DKG Project Management Ltd | Construction | 2026 |
| DKS Resin Bound and Property Solutions Ltd. | Construction | 2024 |
| DKS Training Services Ltd | Professional & scientific | 2019 |
| DL Car and Commercial Sales Ltd | Wholesale & retail | 2021 |
| DL Ifone Centre Ltd | Wholesale & retail | 2024 |
| DL1 Recovery Ltd | Wholesale & retail | 2023 |
| DL3 Partners Limited | Education | 2026 |
| DL888DL Limited | Hospitality | 2024 |
| DLS Rigging Ltd | Mining & quarrying | 2018 |
| DLT8 Limited | Hospitality | 2025 |
| DLV Autos Limited | Wholesale & retail | 2021 |
| DM Prime Properties Ltd | Real estate | 2024 |
| DMA Law Limited | Professional & scientific | 2015 |
| DMH Electrical and Renewable Ltd | Construction | 2022 |
| DMH Renewables Ltd | Extraterritorial | 2024 |
| DMJ Ventures Limited | Hospitality | 2016 |
| DML Financial Planning Ltd | Financial services | 2010 |
| DML Properties (North East) Limited | Real estate | 2020 |
| Dmma Limited | Financial services | 2012 |
| DMR Property Maintenance & Landscaping Ltd | Administrative & support | 2025 |
| DMW Brickwork Ltd | Construction | 2018 |
| DND Engineering Northeast Ltd | Manufacturing | 2023 |
| DNE Transport and Business Solutions Ltd | Transport & logistics | 2025 |
| Dobelievhm Ltd | Wholesale & retail | 2026 |