| Adey M Ltd | Administrative & support | 2013 |
| ADK Financial Services Ltd | Administrative & support | 2020 |
| Air Compressors North East Limited | Manufacturing | 2025 |
| Allen Mason & Sons (Herrington) Limited | Construction | 1973 |
| Apex Cables Limited | Manufacturing | 1979 |
| Aqumen QS Services Limited | Professional & scientific | 2020 |
| Artech Lighting Limited | Manufacturing | 2013 |
| Atmp Manufacturing Community Limited | Other services | 2015 |
| B & Q Groundworks Limited | Construction | 2016 |
| Beyond Altitude Limited | Professional & scientific | 2025 |
| Bluenergy Hydro Ltd | Professional & scientific | 2012 |
| BR Business Advisory Services Limited | Administrative & support | 2014 |
| Britclean North East Limited | Administrative & support | 2025 |
| C P 2020 Property Ltd | Real estate | 2020 |
| Calamander Developments Limited | Real estate | 2001 |
| Canterbury Consultants Ltd | Professional & scientific | 2005 |
| Cera Investments Ltd | Real estate | 2023 |
| Chloes Creative Cards Limited | Arts & recreation | 2012 |
| Counting North Group Limited | Financial services | 2020 |
| Counting North Limited | Professional & scientific | 2014 |
| D Wilson Products Limited | Wholesale & retail | 2023 |
| D&M Services (North East) Ltd | Financial services | 2022 |
| DC Developments (NE) Ltd | Construction | 2024 |
| DCJ Building Supplies Ltd | Wholesale & retail | 2024 |
| Ds&H Development Management Ltd | Administrative & support | 2017 |
| Dunelm Foodstores Ltd | Wholesale & retail | 2001 |
| Durham City Interiors Ltd | Wholesale & retail | 2020 |
| Durham City Shopmobility | Other services | 2000 |
| Durham Indoor Bowling Community Association Limited | Arts & recreation | 1991 |
| Durham Pumps Limited | Manufacturing | 2001 |
| Durham School of English Ltd | Education | 2018 |
| Durham Vintage Ltd | Wholesale & retail | 2023 |
| Durham Vintage Superstore Ltd | Wholesale & retail | 2023 |
| EW Services (UK) Limited | Real estate | 1999 |
| Extec Consulting Ltd | Professional & scientific | 2019 |
| Form Construct Limited | Construction | 2021 |
| Form Properties (NEF) Limited | Construction | 2021 |
| Form Properties (NEF2) Limited | Construction | 2022 |
| Form Properties Limited | Construction | 2021 |
| Global Enterprise (EU) Limited | Construction | 2014 |
| Hardman Ross Consulting Limited | Professional & scientific | 2011 |
| Heat EX Tube Limited | Manufacturing | 2020 |
| Hunter Energy Limited | Professional & scientific | 2021 |
| I M Property Services Ltd | Real estate | 2026 |
| Innovation Power Hire Limited | Energy | 1997 |
| Innovation Power Limited | Energy | 2013 |
| Innovation Property (NE) Limited | Real estate | 2023 |
| J.B. Concrete Protection Limited | Other services | 1987 |
| Joose Energy Holdings Ltd | Financial services | 2024 |
| L&B Travel Limited | Transport & logistics | 2016 |
| Landmark Accountancy Limited | Extraterritorial | 2015 |
| Leonard's Coffee House Limited | Hospitality | 2005 |
| Lovegreen Design Limited | Professional & scientific | 2022 |
| Mccluskey Roofing (NE) Ltd | Construction | 2024 |
| Mckenna (Plasterers) Limited | Construction | 1976 |
| Media Services and Supplies (UK) Limited | Wholesale & retail | 2002 |
| Michael Smith Electrical Services Limited | Energy | 2008 |
| Middlestone Investments Limited | Financial services | 2026 |
| Mike Leveratt Consultants (MLC) Ltd | Construction | 2021 |
| ML & DL Developments Limited | Construction | 2021 |
| Mollys Taxis Ltd | Transport & logistics | 2018 |
| Monzu Real Estate Limited | Professional & scientific | 2014 |
| Morgan & Newby Engineering Ltd | Construction | 2024 |
| My Practice Partner Ltd | Extraterritorial | 2017 |
| Northyoke Ltd | Extraterritorial | 2012 |
| One Leisure (Durham) Limited | Professional & scientific | 2001 |
| One-Nor Ltd | Manufacturing | 2014 |
| One-Nor Property Rental and Development Ltd | Real estate | 2021 |
| P Wade Social Care Limited | Health & social care | 2016 |
| Quayside Vintage Ltd | Wholesale & retail | 2023 |
| Rasdigital Agency Limited | Information & communication | 2021 |
| Redfox Ccds Ltd | Information & communication | 2011 |
| Sanctuary Property Services (Durham) Limited | Households | 2012 |
| Shaun Bowes Ltd | Construction | 2018 |
| Stamps by Chloe Limited | Extraterritorial | 2012 |
| Stokel Limited | Administrative & support | 2022 |
| TCD Durham Ltd | Hospitality | 2018 |
| Teal Vision Ltd | Professional & scientific | 2018 |
| Tellus Geoconsult Ltd | Professional & scientific | 2024 |
| THE English Rose Cafe Ltd | Hospitality | 2017 |
| THE Loft Ladder Ltd | Real estate | 2014 |
| THE Other Retail Group LLP | | 2010 |
| This Retail Ltd | Hospitality | 2025 |
| Torg (One) Ltd | Real estate | 2015 |
| Torg (Two) Limited | Real estate | 2025 |
| TOW Law Developments Ltd. | Real estate | 2017 |
| Troughear Suit Hire Limited | Wholesale & retail | 2004 |
| Tube Supply Limited | Manufacturing | 2020 |
| UP North Group NE Limited | Wholesale & retail | 2020 |
| Vimma Energy Ltd | Professional & scientific | 2025 |
| Vista HR Limited | Professional & scientific | 2024 |
| WH Newco 502 Limited | Financial services | 2026 |
| Wild & Funk Limited | Wholesale & retail | 2009 |