| Dorsal Energy Ltd | Manufacturing | 2025 |
| Dosie Trans Ltd | Transport & logistics | 2024 |
| DOT Cottons Ltd | Other services | 2017 |
| Douglas Cowper Ltd | Administrative & support | 2021 |
| Douglas Vertical Services Ltd | Manufacturing | 2026 |
| Douro Property Company Ltd | Real estate | 2017 |
| Dovedale Convenience Store Ltd | Wholesale & retail | 2023 |
| Doves Coaches Limited | Transport & logistics | 2024 |
| Down to the Wyre Limited | Other services | 2022 |
| Downeys of Barnes Limited | Hospitality | 2017 |
| Downeys of Pallion Limited | Hospitality | 2016 |
| Downeys of Roker Ltd | Hospitality | 2014 |
| Doxford Engineering Limited | Professional & scientific | 2004 |
| Doxford Pizza Ltd | Hospitality | 2020 |
| Doxford PUB Company Limited | Hospitality | 2017 |
| Doxy Runners C.I.C. | Arts & recreation | 2025 |
| DP Digital Services Limited | Wholesale & retail | 2019 |
| DPH Engineering (North East) Limited | Construction | 2011 |
| DPJ Elevate Impact CIC | Education | 2026 |
| DPR Wealth Management Limited | Professional & scientific | 2023 |
| DPS Northern Building and Maintenance Ltd | Construction | 2014 |
| DPS Northern Facilities Management Ltd | Construction | 2025 |
| DR Builders (North East) Limited | Construction | 2007 |
| DR Code Limited | Information & communication | 2026 |
| DR Funkenstein Limited | Wholesale & retail | 2019 |
| DR Properties (Sunderland) Limited | Real estate | 2025 |
| DR Q'S Food Factory Limited | Hospitality | 2019 |
| DR Q'S Grill and Pizza Limited | Hospitality | 2021 |
| DR Ruth Adebiyi Limited | Health & social care | 2023 |
| Dragu Building Limited | Construction | 2025 |
| Dream Closet Ltd | Wholesale & retail | 2018 |
| Drippyuk Ltd | Wholesale & retail | 2024 |
| Drking Building Services Limited | Construction | 2017 |
| Drmo Affordable Guarantor Service Ltd | Administrative & support | 2025 |
| Dropa Arts Ltd | Wholesale & retail | 2024 |
| DSA Building Performance Limited | Professional & scientific | 2002 |
| DSS Holdings Ltd | Manufacturing | 2015 |
| DST Certified Ltd | Professional & scientific | 2026 |
| DT Foods Ltd | Hospitality | 2019 |
| DT Joinery NE Limited | Construction | 2022 |
| DT Jointing Ltd | Construction | 2023 |
| DT TYE Logistics Ltd | Transport & logistics | 2025 |
| Dtattz Studio Limited | Other services | 2020 |
| DTB GAS Limited | Construction | 2026 |
| DTB Properties NE Limited | Real estate | 2026 |
| DU Property Management Limited | Households | 2021 |
| Duc-Okeysons Ltd | Administrative & support | 2025 |
| DUE4DELIVERY Ltd | Transport & logistics | 2023 |
| Duke Fitness C.I.C. | Health & social care | 2022 |
| Duke Power Engineering Limited | Construction | 2012 |
| Dulai Enterprises Limited | Hospitality | 2012 |
| Dunelm Associates (T&D) Ltd | Education | 2010 |
| Dunn House Accommodation RTM Company Limited | Households | 2021 |
| Dunningham Decorators (Yorkshire) Limited | Extraterritorial | 1982 |
| Duong Denny Ltd | Wholesale & retail | 2025 |
| Durham BED and Furniture Centre Cramlington Ltd | Wholesale & retail | 2020 |
| Durham BED and Furniture Centre Galleries Ltd | Wholesale & retail | 2020 |
| Durham BED and Furniture Centre South Shields Ltd | Wholesale & retail | 2020 |
| Durham BED and Furniture Centre Sunderland Ltd | Wholesale & retail | 2020 |
| Durham BED and Furniture Centre Washington Ltd | Wholesale & retail | 2020 |
| Durham BED and Furniture Group Ltd | Wholesale & retail | 2020 |
| Durham BED Centre Aycliffe Ltd | Wholesale & retail | 2021 |
| Durham Blinds Limited | Manufacturing | 2013 |
| Durham Driveways and Patios Ltd | Construction | 2026 |
| Durham Eco Grass Ltd | Manufacturing | 2025 |
| Durham Enterprises Limited | Administrative & support | 2015 |
| Durham Estates Limited | Real estate | 1990 |
| Durham Fencing and Sheds Ltd | Wholesale & retail | 2025 |
| Durham Groundworks and Construction Ltd | Construction | 2025 |
| Durham Home Improvements Ltd | Wholesale & retail | 2025 |
| Durham Open Learning College Limited | Education | 2011 |
| Durham Plumbing Supplies Limited | Professional & scientific | 2005 |
| Durham Property Developments Limited | Construction | 2016 |
| Durham Render Specialists Ltd | Wholesale & retail | 2025 |
| Durham Road Foods Ltd | Hospitality | 2025 |
| Durham Road Hand Carwash Ltd | Administrative & support | 2020 |
| Durham Sofa Company Ltd | Manufacturing | 2021 |
| DVS Enterprise Ltd | Wholesale & retail | 2018 |
| DW Property Maintenance (UK) Limited | | 2006 |
| Dwstephenson Ltd | Wholesale & retail | 2025 |
| Dwtproperty Ltd | Real estate | 2025 |
| Dylan Peel Brickwork Ltd | Construction | 2025 |
| DYLAN60 Services Limited | Manufacturing | 2012 |
| Dynamic Intensives Ltd | Education | 2025 |
| Dynamic Training Specialists Ltd | Education | 2019 |
| Dynamic Travel NE Ltd | Transport & logistics | 2024 |
| Dynamick Limited | Financial services | 2020 |
| Dynamique Arts C.I.C. | Arts & recreation | 2016 |
| E King (Steelfixing) Limited | Construction | 2009 |
| E King Properties Ltd | Real estate | 2015 |
| E&E Civils NE Ltd | Construction | 2025 |
| E&I Global Services Ltd | Wholesale & retail | 2026 |
| E&M Properties North East Ltd | Real estate | 2024 |
| E.Hall (Tripe & Poultry) Limited | Manufacturing | 1969 |
| E.Lee Trading Ltd | Wholesale & retail | 2025 |
| E.N. Transport Limited | Transport & logistics | 2020 |
| E2 Decorators Limited | Other services | 2009 |
| E2 Property Group Ltd | Real estate | 2024 |
| EA Domestic Services Ltd | Administrative & support | 2026 |
| EAC Systems Ltd | Wholesale & retail | 2013 |