| Durham Heat Pumps Limited | Construction | 2024 |
| Durham Hospitality Ltd | Administrative & support | 2025 |
| Durham Housing Ltd | Real estate | 2023 |
| Durham Interiors Ltd | Wholesale & retail | 2015 |
| Durham Jazz Festival CIC | Arts & recreation | 2025 |
| Durham Kumon Ltd | Education | 2025 |
| Durham Lawnz Ltd | Administrative & support | 2018 |
| Durham Leisure Group Limited | Financial services | 2019 |
| Durham Leisure Limited | Hospitality | 2019 |
| Durham Lettings Limited | Real estate | 2018 |
| Durham Lounge Ltd | Hospitality | 2024 |
| Durham Market Place Ltd | Real estate | 2018 |
| Durham Markets Company Limited | Wholesale & retail | 1992 |
| Durham Masonic Hall (1868) Limited | Real estate | 2026 |
| Durham Masonic Hall Ltd | Hospitality | 2014 |
| Durham Masonic Hall Trading Limited | Real estate | 2024 |
| Durham Medical Holdings Limited | Financial services | 2015 |
| Durham Medtech Ltd | Hospitality | 2020 |
| Durham Metals Ltd | Water & waste | 2022 |
| Durham Microlights Ltd | Arts & recreation | 2016 |
| Durham Micropub Ltd. | Hospitality | 2015 |
| Durham Miners Gala Ltd | Administrative & support | 2025 |
| Durham Miners' Association | Other services | 2017 |
| Durham Minibuses Ltd | Extraterritorial | 2020 |
| Durham Moor Limited | Hospitality | 2023 |
| Durham Mortgage Solutions Limited | Financial services | 2019 |
| Durham MOT + Service Centre Ltd | Wholesale & retail | 2024 |
| Durham Mount Oswald Limited | Real estate | 2018 |
| Durham Mountaineering Ltd | Manufacturing | 2019 |
| Durham Music Hub CIC | Education | 2026 |
| Durham Musical Theatre Company Limited | Arts & recreation | 2014 |
| Durham Musical Youth Theatre Ltd | Arts & recreation | 2024 |
| Durham MVR Ltd | Hospitality | 2025 |
| Durham Paving Services Limited | Construction | 2015 |
| Durham Phones and Computers Ltd | Other services | 2025 |
| Durham Project Consultancy Ltd | Professional & scientific | 2013 |
| Durham Property Experts Ltd | Professional & scientific | 2022 |
| Durham Property Lettings Ltd | Real estate | 2021 |
| Durham Property Management Limited | Real estate | 2018 |
| Durham Property Management NW Ltd | Real estate | 2024 |
| Durham Public House Company Limited | Hospitality | 2018 |
| Durham Regatta | Arts & recreation | 2010 |
| Durham Render Centre Limited | Wholesale & retail | 1992 |
| Durham River Trips Limited | Transport & logistics | 1988 |
| Durham School Langley Foundation | Education | 2011 |
| Durham Self Store Ltd | Administrative & support | 2009 |
| Durham Smile Solutions Limited | Health & social care | 2021 |
| Durham Specialist Car Services Limited | Wholesale & retail | 2013 |
| Durham Spirits Ltd | Wholesale & retail | 2023 |
| Durham Sporting Goods Ltd | Wholesale & retail | 2012 |
| Durham Stoves and Fireplaces Limited | Construction | 2017 |
| Durham Students' Union | Hospitality | 2011 |
| Durham Surgery Limited | Health & social care | 2015 |
| Durham Sustainable Solutions Ltd | Professional & scientific | 2021 |
| Durham Taxi’S Limited | Transport & logistics | 2025 |
| Durham Tech Ltd | Wholesale & retail | 2021 |
| Durham Tees Transport Ltd | Wholesale & retail | 2016 |
| Durham Timber Products Limited | Manufacturing | 2013 |
| Durham University Developments Limited | Real estate | 1992 |
| Durham University Enterprise Ltd | Administrative & support | 1993 |
| Durham Vintage and Antiques Limited | Wholesale & retail | 2021 |
| Durham Window and Door Centre Limited | Construction | 2003 |
| Durham Women's Football Club Ltd | Arts & recreation | 2013 |
| Durham Workspace Ltd | Real estate | 2018 |
| DURHAM-1 MVR Ltd | Hospitality | 2025 |
| Durhamcity.Net Limited | Professional & scientific | 2002 |
| Durmech Solutions Ltd | Administrative & support | 2017 |
| Dursen Ltd | Professional & scientific | 2019 |
| Durtech Cloud Solutions Ltd | Information & communication | 2026 |
| Dusk 'TIL Dawn Entertainment Limited | Arts & recreation | 2006 |
| DVG Consultancy Limited | Professional & scientific | 2017 |
| DW Energy Ltd | Energy | 2026 |
| DW Renewables North East Ltd | Wholesale & retail | 2023 |
| DWB Drywall Limited | Construction | 2020 |
| Dwell Well Ltd | Information & communication | 2018 |
| Dwelsolutions Ltd | Information & communication | 2015 |
| DWG LET Limited | Construction | 2016 |
| DWG Lettings Ltd | Real estate | 2024 |
| DWM Property Group Ltd | Real estate | 2023 |
| DWR (33) Services Ltd | Professional & scientific | 2018 |
| DWT Systems Ltd | Information & communication | 2016 |
| Dyah Ltd | Wholesale & retail | 2025 |
| Dynamic ARC Limited | Manufacturing | 1998 |
| Dynamic Lifestyle CIC | Education | 2024 |
| Dynamic Transport Planning Limited | Professional & scientific | 2017 |
| Dyra Luxe Ltd | Wholesale & retail | 2020 |
| Dyson Real Estate Ltd | Real estate | 2020 |
| E & a Brickwork NE Ltd | Construction | 2023 |
| E & J Clark Ltd. | Real estate | 2018 |
| E & R Building Services Limited | Construction | 2024 |
| E Beeston Ltd | Information & communication | 2023 |
| E D P Drug & Alcohol Services | Health & social care | 1987 |
| E K M Properties Ltd | Real estate | 2018 |
| E R Humshaugh 2024 Limited | Construction | 2024 |
| E-Smart Commerce Ltd | Wholesale & retail | 2023 |
| E.J.W Utilities Ltd | Construction | 2024 |
| E.S. Systems Ltd | Information & communication | 1998 |
| EAE Group UK Ltd | Wholesale & retail | 2025 |
| Eagle International Enterprises Limited | Administrative & support | 2002 |
| Eagle Store Ltd | Wholesale & retail | 2025 |