| Deep Green JV (Darlington) Limited | Information & communication | 2025 |
| Deep Green JV (Glasgow) Ltd | Information & communication | 2025 |
| Deep Green JV (London) Ltd | Information & communication | 2025 |
| Deep Green JV (York) Limited | Information & communication | 2025 |
| Deep Green Technologies (Assets) Limited | Financial services | 2023 |
| Deep Green Technologies (Capital Assets) Ltd | Information & communication | 2024 |
| Deep Green Technologies (Services) Limited | Other services | 2023 |
| Deep Green Technologies Ltd | Information & communication | 2021 |
| Delaval Accountancy Limited | Professional & scientific | 2014 |
| Desiderata Psychotherapy Ltd | Health & social care | 2023 |
| Design Forge Solutions Ltd | Professional & scientific | 2024 |
| Design Lines Architects Limited | Professional & scientific | 2006 |
| Deus Boxing Limited | Arts & recreation | 2025 |
| Deusboxing Gym Ltd | Arts & recreation | 2025 |
| Devin Consulting Limited | Professional & scientific | 2005 |
| DFB Renewables Ltd | Extraterritorial | 2024 |
| DFM Accountancy Services Ltd | Professional & scientific | 2016 |
| DG Services (NE) Limited | Construction | 2013 |
| DI Mascio’S Ices Ltd | Wholesale & retail | 2023 |
| Diamond Aesthetics N.E Ltd | Other services | 2021 |
| Diamonds Mobile Valeting Specialists Ltd | Other services | 2025 |
| Digital Product Academy Ltd | Wholesale & retail | 2026 |
| Digitalab Holdings Ltd | Financial services | 2022 |
| Digitalab Limited | Manufacturing | 2015 |
| Digitax Electronics UK Limited | Administrative & support | 1989 |
| Diglitdear Engineering Limited | Professional & scientific | 2007 |
| DIL and the Bear Limited | Hospitality | 2012 |
| Dimana Ltd | Hospitality | 2025 |
| DIN Go AI Limited | Wholesale & retail | 2025 |
| Dine OUT Blyth Limited | Hospitality | 2026 |
| Diogenis Limited | Hospitality | 2015 |
| DIP Club Limited | Health & social care | 2023 |
| DIP Club Ventures Limited | Health & social care | 2026 |
| Direct Windows (North East) Limited | Manufacturing | 2011 |
| Discover Agile Ltd | Information & communication | 2020 |
| Discover Solutions Ltd | Information & communication | 2022 |
| Distripak Limited | Extraterritorial | 1971 |
| Dixon TTL Limited | Financial services | 2012 |
| DIY Media Ltd | Wholesale & retail | 2009 |
| DJ Packaging Limited | Administrative & support | 2024 |
| DJ Patterson Builders Ltd | Construction | 2007 |
| Djpp Limited | Real estate | 2024 |
| DLC Waste Services Ltd | Water & waste | 2025 |
| DLH Wealth Investment Limited | Real estate | 2023 |
| DMH and Associates Ltd | Administrative & support | 2013 |
| DN Transport North East Limited | Transport & logistics | 2026 |
| Dobson & Surrey Limited | Construction | 1976 |
| Dockwray Ltd | Professional & scientific | 2014 |
| Doctor Seaweed Limited | Hospitality | 2013 |
| Dodgins Eatery Ltd | Hospitality | 2025 |
| Dog Grooming at Darcy's Ltd | Other services | 2024 |
| Doggy Delish Ltd | Wholesale & retail | 2024 |
| Dolphin Tynemouth Ltd | Hospitality | 2025 |
| DOM Timney Consulting Limited | Professional & scientific | 2026 |
| Domino Technology Limited | Information & communication | 2018 |
| Dommus Cattus Ltd | Information & communication | 2022 |
| Double L Creative Ltd | Professional & scientific | 2025 |
| Double ZEE Developments Ltd | Real estate | 2026 |
| Dove House Cullercoats (Management) Limited | Real estate | 2007 |
| Down and OUT Ltd | Hospitality | 2024 |
| Downs Leisure Group Ltd | Hospitality | 2021 |
| Doxford Camping Ltd | Hospitality | 2025 |
| Doyle Law Limited | Professional & scientific | 2024 |
| DP General Ltd | Construction | 2012 |
| DPG North East Ltd | Construction | 2022 |
| DPH Construction (North East) Limited | Construction | 2005 |
| DR Industrial Ltd | Construction | 2025 |
| Drchriselliott Limited | Health & social care | 2017 |
| Dreaming Beds Ltd | Wholesale & retail | 2023 |
| Dreams Healthcare Recruitment Ltd | Health & social care | 2017 |
| Dreams Heathcare Limited | Health & social care | 2012 |
| Dressmezee Limited | Wholesale & retail | 2015 |
| Driway International Technologies Limited | Wholesale & retail | 2019 |
| Droh Limited | Manufacturing | 2023 |
| Drool Academy Ltd | Other services | 2024 |
| DSB Paints Limited | Construction | 2025 |
| DSC Electrical NE Ltd | Construction | 2014 |
| DSC Resilience CIC | Administrative & support | 2018 |
| DSM Long Property Limited | Real estate | 2024 |
| DTF Couriers Ltd | Transport & logistics | 2006 |
| Duncan HR Limited | Professional & scientific | 2010 |
| Durham and Newcastle Diocesan Learning Trust | Education | 2017 |
| Dustys Painting Company Limited | Construction | 2026 |
| Dynamic Deliveries Ltd | Transport & logistics | 2020 |
| Dynamic DUO Ltd | Administrative & support | 2019 |
| Dynamic Kitchen Limited | Wholesale & retail | 2022 |
| E&M OIL and GAS Services Ltd | Extraterritorial | 2018 |
| E-Comprocessing Ltd | Professional & scientific | 2011 |
| E. Hoult (Howdon) Ltd | Wholesale & retail | 2012 |
| E.R.C Auto's Ltd | Wholesale & retail | 2024 |
| Eadd Properties Limited | Households | 2025 |
| Eagles Wings Consultancy Ltd | Professional & scientific | 2021 |
| Earls Direct Limited | Wholesale & retail | 2017 |
| Earluxe Ltd | Health & social care | 2024 |
| Earth Sea Love Community Interest Company | Professional & scientific | 2022 |
| Eastcoast Martial Arts Ltd | Education | 2025 |
| Eastquayit Limited | Information & communication | 2011 |
| Easy Access Garage Doors Limited | Manufacturing | 2002 |
| Easyblock Ltd | Wholesale & retail | 2021 |
| Ebdc Holdings Limited | Extraterritorial | 2020 |