| Drum Fast Fit and Performance Ltd | Manufacturing | 2023 |
| Dryad Properties Ltd | Real estate | 2018 |
| DSM Domestic Ltd | Administrative & support | 2025 |
| DSM Plumbing and Heating Ltd | Construction | 2024 |
| DSW (NE) Limited | Manufacturing | 2008 |
| DT Power Solutions Limited | Administrative & support | 2015 |
| DTR Services (North East) Limited | Information & communication | 2017 |
| DU Black Ltd | Professional & scientific | 2013 |
| Dumblepaws Ltd | Other services | 2019 |
| Durham Agency Against Crime Limited | Administrative & support | 1991 |
| Durham Briques Ltd | Real estate | 2025 |
| Durham City Cabs Ltd | Transport & logistics | 2025 |
| Durham City Scuba Ltd | Arts & recreation | 2026 |
| Durham County Cricket Club | Extraterritorial | 1991 |
| Durham County Cricket Club Developments Limited | Extraterritorial | 2015 |
| Durham County Cricket Foundation | Arts & recreation | 2008 |
| Durham County Football Association Limited | Arts & recreation | 2001 |
| Durham Cricket C.I.C. | Arts & recreation | 2004 |
| Durham Cricket Events Limited | Hospitality | 2020 |
| Durham Kris Aesthetics Ltd | Other services | 2025 |
| Durham Property Ltd | Construction | 2018 |
| Durham Property Services Ltd | Real estate | 2025 |
| DWF Blade Tech Ltd | Other services | 2023 |
| Dynamic Polymer Systems Limited | Wholesale & retail | 2022 |
| E & H Commercial Vehicle Repairs and Maintenance Ltd | Wholesale & retail | 2017 |
| E a Lifestyle Consultants Ltd | Wholesale & retail | 2023 |
| E&G Rentals Limited | Real estate | 2026 |
| E-Finite Limited | Information & communication | 1996 |
| E.H.C. Consultancy Limited | Real estate | 2016 |
| Eardulph Ltd | Real estate | 2020 |
| Easton Care Ltd | Health & social care | 2024 |
| Easton Community CIC | Public administration | 2025 |
| Easy Roads Ltd | Education | 2026 |
| Ebony Hair Salon Limited | Other services | 2009 |
| EC Financial Planning Limited | Professional & scientific | 2021 |
| Eco-One Insulation Ltd | Construction | 2022 |
| Edson Radiological Services Limited | Health & social care | 2019 |
| Edward Thompson (Printers) Limited | Manufacturing | 1962 |
| Edward Thompson Group Limited | Professional & scientific | 2002 |
| Effective Professional Interactions Ltd | Education | 2003 |
| Efficient Insulation (NE) Limited | Construction | 2025 |
| Elden Holdings Ltd | Financial services | 2025 |
| Elec-Tech North East Ltd | Construction | 2021 |
| Electomotive Ltd | Wholesale & retail | 2024 |
| Electraheat North East Limited | Construction | 2022 |
| Electron Systems Limited | Manufacturing | 1999 |
| Elevation Wind Services Limited | Manufacturing | 2024 |
| Eljay Research Limited | Professional & scientific | 2005 |
| Elliott Civils Ltd | Construction | 2022 |
| Elmoline Limited | Wholesale & retail | 2001 |
| Ememsee Ltd | Real estate | 2025 |
| Emerald Consulting (UK) Limited | Professional & scientific | 2009 |
| Emma Tolley Consulting Limited | Professional & scientific | 2024 |
| Emmerson ADR Services Limited | Professional & scientific | 2023 |
| Emmys CLS Ltd | Hospitality | 2021 |
| Emtec Engineering Ltd | Construction | 2022 |
| Energist Installation Services Ltd | Construction | 2021 |
| Energist Solutions Ltd | Construction | 2020 |
| Energy Group Services Limited | Professional & scientific | 2018 |
| Energy Group Supplies Limited | Energy | 2021 |
| Energy OWL Utilities Ltd | Administrative & support | 2017 |
| Engcare Ltd | Professional & scientific | 2024 |
| Engineering and Technology Services Limited | Manufacturing | 2018 |
| Enviro Developments (NE) Ltd | Real estate | 2019 |
| Envirorod Limited | Water & waste | 2018 |
| EPM Productions Ltd | Arts & recreation | 2024 |
| Equi-Venture (NE) Ltd | Financial services | 2025 |
| ER Megill (Project Management) Ltd | Construction | 2021 |
| Escape Hairdressing Limited | Other services | 2000 |
| Esprit Global Limited | Professional & scientific | 2003 |
| Essential Electrical Solutions Ltd | Construction | 2018 |
| Eternity(The Cave) CIC | Water & waste | 2021 |
| EV Rescue Ltd | Construction | 2026 |
| EV Smart (UK) Ltd | Energy | 2020 |
| Evelle Bakes Limited | Hospitality | 2026 |
| Everything Radiography Ltd | Information & communication | 2025 |
| Evolution Energy North East Ltd | Construction | 2022 |
| Ewart Wealth Management Limited | Professional & scientific | 2014 |
| Excel Properties NE Ltd | Real estate | 2025 |
| Excel RAC Limited | Energy | 2011 |
| Excel Racing Ltd | Arts & recreation | 2026 |
| Excelencia Limited | Professional & scientific | 2019 |
| Expert Defence Services Ltd | Professional & scientific | 2021 |
| Extrahold Limited | Real estate | 2009 |
| F Tiffen Building Services Ltd | Construction | 2015 |
| F1 Chester Ltd | Administrative & support | 2018 |
| FAB NE Limited | Construction | 2016 |
| Faith in Beauty Aesthetics Ltd | Other services | 2023 |
| Faith Meets Love Ltd | Information & communication | 2018 |
| Falcon Foods Limited | Hospitality | 2011 |
| Farah MO Ltd | Health & social care | 2020 |
| Fast React NE Ltd | Construction | 2024 |
| Fausto Country Limited | Hospitality | 2026 |
| Fern LEA Prestige Ltd | Construction | 2023 |
| Figaro Figaro Figaro Limited | Hospitality | 2018 |
| Filodrive Limited | Administrative & support | 2016 |
| Finance 4 YOU Limited | Construction | 2018 |
| Find ME a Broker Ltd | Financial services | 2024 |
| Finis Ludum Ltd | Real estate | 2025 |
| Finsense Academy Ltd | Professional & scientific | 2025 |