| Debbiejuddhr Limited | Administrative & support | 2019 |
| Deborah Clark Financial Consultancy Limited | Professional & scientific | 2023 |
| Decal Additives Ltd | Extraterritorial | 2013 |
| Decorbake Consett Ltd | Wholesale & retail | 2014 |
| Deliverco Ltd | Hospitality | 2021 |
| Dellner Romag Limited | Manufacturing | 2020 |
| Delmont Project Services Ltd | Construction | 2009 |
| Delmont Property Ltd | Real estate | 2026 |
| Demanded Streetwear Ltd | Wholesale & retail | 2025 |
| Denby Bullz Limited | Wholesale & retail | 2025 |
| Dere Street Developments NE Ltd | Construction | 2025 |
| Derek Emery Limited | Administrative & support | 2012 |
| Derwent Glass Supplies Ltd | Construction | 2011 |
| Derwent Rentals Limited | Real estate | 2020 |
| Derwent Valley Allstars Limited | Arts & recreation | 2024 |
| Derwent Valley Financial Advice Limited | Financial services | 2019 |
| Derwent Valley Sports Initiative Community Interest Company | Arts & recreation | 2023 |
| Derwentside Business Network C.I.C. | Education | 2017 |
| Derwentside Caravans Limited | Transport & logistics | 2005 |
| Derwentside Enterprise Agency C.I.C | Other services | 1982 |
| Derwentside Estates Limited | Construction | 2026 |
| Derwentside GAS Limited | Construction | 2007 |
| Derwentside Healthcare Limited | Health & social care | 2015 |
| Derwentside Inspection Services Ltd | Mining & quarrying | 2021 |
| Design X-Press Limited | Administrative & support | 1999 |
| Designed With a Twist Ltd | Manufacturing | 2021 |
| Devine Chemicals Limited | Wholesale & retail | 1994 |
| Dfmr Ltd | Households | 2022 |
| DGH Electrical Ltd | Manufacturing | 2023 |
| DH Electrical Contractors Ltd | Construction | 2020 |
| DH Storage and Property Ltd | Other services | 2022 |
| DH1 Brands Ltd | Wholesale & retail | 2022 |
| DH8 Events & Bars Ltd | Hospitality | 2025 |
| DH8 Pest Control Ltd | Other services | 2022 |
| Dhillion Stores Ltd | Wholesale & retail | 2017 |
| Dhvapes (North East) Ltd | Wholesale & retail | 2023 |
| Diagnostic and Vehicle Engine Services (Daves) Ltd | Wholesale & retail | 2018 |
| Diamonds Elite and Recreational Cheerleading C.I.C. | Education | 2026 |
| Digicon Bidco Limited | Financial services | 2025 |
| Dipwood Holdings Limited | Financial services | 2017 |
| Dipwood Storage & Distribution Limited | Manufacturing | 2022 |
| DJ Distributors Ltd | Wholesale & retail | 2025 |
| DJL Business Solutions Ltd | Financial services | 2019 |
| DJP NE Properties Ltd | Real estate | 2026 |
| DL Training (North East) Limited | Construction | 2017 |
| DM Conny Surveyor Ltd | Construction | 2015 |
| DMC Assets Ltd | Real estate | 2023 |
| DMR (Consett) Ltd | Financial services | 2024 |
| DNH Limited | Professional & scientific | 2018 |
| Donnelly Electrical Ltd | Construction | 2025 |
| Douglas Beveridge Estate Ltd | Real estate | 2019 |
| DR JON Levick Limited | Professional & scientific | 2012 |
| Dragonfly Transformation Limited | Administrative & support | 2018 |
| Dressmaking by Kaylean Ltd | Manufacturing | 2026 |
| Driza Holdings Ltd | Real estate | 2024 |
| Drombane Temple Ltd | Health & social care | 2024 |
| Drovers Studio Limited | Health & social care | 2026 |
| Dryright Limited | Administrative & support | 2008 |
| DSG Detailing & JET Washing Limited | Administrative & support | 2024 |
| DST Insights Limited | Information & communication | 2024 |
| Dubblr Ltd | Professional & scientific | 2025 |
| Duke of Wellington (Consett) Ltd | Hospitality | 2024 |
| Duncan Fleck Head Gardener Ltd. | Administrative & support | 2013 |
| Dunelm Consultants Limited | Information & communication | 2018 |
| Dunelm EL Tossal Limited | Professional & scientific | 2014 |
| Durham Community Tennis Partnership Community Interest Company | Arts & recreation | 2018 |
| Durham Ductwork Ltd | Construction | 2026 |
| Durham Fell and Field Ltd | Wholesale & retail | 2026 |
| Durham House Developments Ltd | Real estate | 2025 |
| Durham Legal Services UK Ltd | Professional & scientific | 2004 |
| Durham Telecoms Limited | Financial services | 2025 |
| DXN REP Club Ltd | Arts & recreation | 2025 |
| Dysart Developments (North East) Limited | Real estate | 1986 |
| Dysart Developments Limited | Construction | 1979 |
| Dysart Management Limited | Administrative & support | 2004 |
| Dysart Residential Limited | Construction | 2005 |
| Dyson Integrity Services Ltd | Professional & scientific | 2021 |
| E & L Developments Ltd | Construction | 2025 |
| E3 Ecology Ltd | Professional & scientific | 2003 |
| Ebchester Village Store Ltd. | Wholesale & retail | 2016 |
| Ebfn Consulting Ltd | Information & communication | 2021 |
| Eboney Home Care Limited | Health & social care | 2005 |
| ECB Rental Properties Ltd | Real estate | 2018 |
| Eco Tight Air Tightness Testing Ltd | Construction | 2026 |
| Eco-Pall LLP | | 2013 |
| Eddie Rods Ltd | Transport & logistics | 2011 |
| Eden Aesthetics Ltd | Other services | 2024 |
| Eden Material Services (U.K.) Limited | Wholesale & retail | 1981 |
| Edengate Mortgage Services Ltd | Financial services | 2020 |
| EDM Property Services Ltd | Real estate | 2026 |
| Effective Dynamics Consultancy Limited | Public administration | 2016 |
| Efficient Heating Solutions North East Limited | Construction | 2022 |
| EJ Wellbeing CIC | Education | 2022 |
| EJL Utilities Ltd | Construction | 2026 |
| EK Cloud Solutions Ltd | Information & communication | 2023 |
| Elaine Kirby & Associates HR Ltd | Administrative & support | 2023 |
| Electron in a Box Ltd | Information & communication | 2019 |
| Elitereach Limited | Professional & scientific | 2026 |
| Elmdale 1970 Limited | Extraterritorial | 2014 |
| Elmtronics Group Limited | Financial services | 2019 |