| Buyova UK Ltd | Wholesale & retail | 2026 |
| Buzzard Lifting & Haulage Ltd | Construction | 2023 |
| BW Inspection Limited | Construction | 2012 |
| BWL Site Support Limited | Construction | 2025 |
| Bwlm Properties Ltd | Real estate | 2025 |
| BY Lavish Occasions Ltd | Wholesale & retail | 2022 |
| Bydand Developments Ltd | Real estate | 2025 |
| Byjutar Ltd | Construction | 2023 |
| Bykare Services Ltd | Administrative & support | 2020 |
| Bykare Solutions (Healthcare) Ltd | Administrative & support | 2025 |
| Byrd & Burgz Limited | Hospitality | 2025 |
| C & C Hair Co Limited | Other services | 2002 |
| C & C Properties NE Limited | Extraterritorial | 2023 |
| C & D Leisure Properties Ltd | Financial services | 2016 |
| C & E Motors Ltd | Wholesale & retail | 2013 |
| C & M (Life & Pensions) Limited | Financial services | 1990 |
| C & M Contractors (NE) Ltd | Construction | 2019 |
| C & R Tyre Services Ltd | Wholesale & retail | 2025 |
| C & S Engineering (NE) Ltd | Professional & scientific | 2014 |
| C B Precision Roofing Ltd | Construction | 2026 |
| C Emery Ltd | Construction | 2025 |
| C J Holdings North East Ltd | Real estate | 2018 |
| C J Wind Height Tech Limited | Manufacturing | 2019 |
| C Jackson Joinery Ltd | Construction | 2017 |
| C Louise Hospitality Limited | Hospitality | 2025 |
| C Marston Electrical Ltd | Manufacturing | 2017 |
| C P Randall Services Limited | Construction | 2013 |
| C P Sinclair Limited | Construction | 2018 |
| C Redman Engineering Services Ltd | Professional & scientific | 2010 |
| C S B Yarm Ltd | Real estate | 2015 |
| C S Consultancy (NE) Ltd | Other services | 2024 |
| C Squared Power Limited | Construction | 2018 |
| C T (North East) Limited | Transport & logistics | 2012 |
| C T Williams Services Limited | Professional & scientific | 2007 |
| C&E Housing Ltd | Real estate | 2024 |
| C&H Plumbing and Heating Ltd | Construction | 2021 |
| C&L Developments (NE) Limited | Construction | 2016 |
| C&M Property Housing Ltd | Real estate | 2025 |
| C&R Legacy Ltd | Other services | 2025 |
| C-A-S Rental’S Ltd | Real estate | 2022 |
| C-Cat Limited | Administrative & support | 2008 |
| C-Store Consultants Ltd | Professional & scientific | 2019 |
| C-Store Services Ltd | Professional & scientific | 2019 |
| C. Riley Roofing Ltd | Construction | 2024 |
| C.A Consultancy and Training Ltd | Professional & scientific | 2019 |
| C.C Rope Access and Paint Services Ltd | Construction | 2023 |
| C.Debnath Limited | Manufacturing | 2018 |
| C.Donnelly Solutions Ltd | Construction | 2025 |
| C.G.K Scaffolding Limited | Construction | 2025 |
| C.I.E. Property Management Ltd | Administrative & support | 2023 |
| C.M Extract Ltd | Manufacturing | 2025 |
| C.R.Blade Services Ltd | Manufacturing | 2018 |
| C.Samson Ltd | Information & communication | 2022 |
| CA Site Safety Solutions Limited | Professional & scientific | 2024 |
| CAB Rigging & Lifting Limited | Professional & scientific | 2019 |
| Cable Installation Consultants Ltd | Manufacturing | 2023 |
| Cable Smart Limited | Information & communication | 2011 |
| CAD One Ltd | Professional & scientific | 2019 |
| Cadara Limited | Real estate | 2008 |
| CAF Properties Ltd | Real estate | 2025 |
| Cafe & Breakfast Ltd | Hospitality | 2025 |
| Cafe Central Park Limited | Hospitality | 2012 |
| Cafe Etch Limited | Hospitality | 2019 |
| Cafe Happy Sapid Ltd | Hospitality | 2023 |
| Cafe Lilli Limited | Hospitality | 2015 |
| CAFEPEARLS1979 Limited | Hospitality | 2025 |
| Cago Medicals Ltd | Health & social care | 2023 |
| Cainwood Electrical Services Limited | Construction | 2022 |
| Cairns Technical Engineering Ltd | Professional & scientific | 2025 |
| Caisley Electrical Limited | Construction | 2024 |
| Cakes and Shakes Middlesbrough Ltd | Hospitality | 2023 |
| Cakes Bakes & Shakes Desserts Middlesbrough Ltd | Wholesale & retail | 2025 |
| Cakrri (NE) Limited | Wholesale & retail | 2021 |
| CAL Scaffolding Ltd | Construction | 2019 |
| Caladian Contracts Ltd | Construction | 2025 |
| Calcilex Educational Services Ltd | Education | 2024 |
| Calcs Residential Services Ltd | Real estate | 2024 |
| Calcs Services Ltd | Professional & scientific | 2020 |
| Caldac Limited | Households | 1979 |
| Caleb Ltd | Real estate | 2023 |
| Calgriff Group Ltd | Professional & scientific | 2024 |
| Calin Electrical Ltd | Construction | 2023 |
| Callum Bendelow Limited | Professional & scientific | 2023 |
| Callum Lewis Joinery Ltd | Construction | 2025 |
| Calm Digital Solutions Limited | Information & communication | 2015 |
| Calm Inductions Limited | Information & communication | 2015 |
| Calma Llama Land Ltd | Information & communication | 2026 |
| Cals Clothing Ltd | Wholesale & retail | 2025 |
| Caltech & Control Ltd | Other services | 2023 |
| CAM Risk Management Ltd | Professional & scientific | 2025 |
| CAM85 IT Limited | Professional & scientific | 2015 |
| Cambridge Lodge Limited | Administrative & support | 1961 |
| Cambridge Square Holding Limited | Real estate | 2024 |
| Cambridge Square Management Company Limited | Households | 2006 |
| Cambridge Square Properties Ltd | Real estate | 2018 |
| Cameron Hunter Engineering Services Limited | Professional & scientific | 2012 |
| Camerons Joinery Ltd | Construction | 2024 |
| Camrose Property Investments Limited | Real estate | 2024 |
| Camsell Trading Ltd | Wholesale & retail | 2022 |
| Camtech Consultancy Services Limited | Professional & scientific | 2019 |