| Boyles Business Solutions Limited | Administrative & support | 2025 |
| Brennan Access Ltd | Construction | 2025 |
| Brett Cummings Limited | Information & communication | 2010 |
| Brians Reptiles Ltd | Wholesale & retail | 2018 |
| Briarside Services Limited | Professional & scientific | 2021 |
| Briarwood Developments Ltd | Construction | 2023 |
| Bridgehome Group Ltd | Real estate | 2024 |
| Bridgewater Maintenance Limited | Real estate | 2009 |
| Bridging Languages Ltd | Professional & scientific | 2023 |
| Bright Sparks PR Limited | Professional & scientific | 2011 |
| Brookside Properties ( NE ) Ltd | Real estate | 2019 |
| Brunch Box Ltd | Hospitality | 2024 |
| BSR Heating & Plumbing Limited | Construction | 2017 |
| Buckleberries Ltd | Information & communication | 2020 |
| Burlow Properties Limited | Real estate | 2019 |
| Burn Lane Limited | Professional & scientific | 2009 |
| Burney Crook Properties Limited | Real estate | 2022 |
| Burrell Wind Service Ltd | Construction | 2025 |
| BUS 2 Limited | Administrative & support | 2017 |
| Business Education Publishers Limited | Information & communication | 1986 |
| Byrom-Hancock Properties Ltd | Real estate | 2024 |
| C & C Trade Cars Ltd | Wholesale & retail | 2022 |
| C & E Carpets & Flooring Limited | Wholesale & retail | 2018 |
| C S Auto Sales Ltd | Wholesale & retail | 2020 |
| C S G Properties Limited | Real estate | 2011 |
| C S Keys & Coding Ltd | Other services | 2023 |
| C S North East Limited | Administrative & support | 2005 |
| C.C.G.M. Ltd | Construction | 2023 |
| C.P.S. Electrical Contractors Limited | Construction | 2003 |
| CAD2CODE Community Interest Company | Education | 2018 |
| Calibre Properties Limited | Real estate | 2002 |
| Callion Advisory Limited | Professional & scientific | 2020 |
| Callum Todd Properties Ltd | Real estate | 2024 |
| Callum Todd Property Maintenance Ltd | Construction | 2026 |
| Calm and Grow CIC | Health & social care | 2025 |
| Calmor Limited | Administrative & support | 2009 |
| Calysta (UK) Ltd | Administrative & support | 2014 |
| Cameron Mallaby Logistics Ltd | Transport & logistics | 2025 |
| Candy Floss Desserts Ltd | Hospitality | 2025 |
| Canney Communities Community Interest Company | Hospitality | 2019 |
| Cantrip Ltd | Wholesale & retail | 2026 |
| Car Safety Centre Ltd | Wholesale & retail | 2016 |
| Carnival Rides Limited | Arts & recreation | 2016 |
| Carpet Repair Tyne & Wear Ltd | Other services | 2026 |
| Carter Transformations Ltd | Hospitality | 2022 |
| CAS Retail Solutions Ltd | Wholesale & retail | 2024 |
| Casey's Barbers Ltd | Other services | 2025 |
| Castle Hill Wylam Limited | Information & communication | 2023 |
| Castle Keys Property Ltd | Real estate | 2019 |
| Castlegreen Construction Limited | Construction | 2023 |
| Castletown Inns Ltd | Hospitality | 2024 |
| Cathedral Coffins Limited | Manufacturing | 2001 |
| Cdlt Properties Ltd | Real estate | 2026 |
| Cedidos Limited | Extraterritorial | 2021 |
| Celebrate With Light Ltd | Hospitality | 2022 |
| Centurion Financial Planning Limited | Financial services | 2006 |
| CGT Notary Public Limited | Professional & scientific | 2021 |
| Chair UP Ltd | Other services | 2026 |
| Chapter 6 Inc Limited | Manufacturing | 1999 |
| Chapter Square Limited | Professional & scientific | 2013 |
| Chapter Thorpe Ltd. | Construction | 2017 |
| Charol Engineering Services Ltd | Information & communication | 2022 |
| Chick-A-Dee Ltd | Transport & logistics | 2022 |
| Chilton Diner Limited | Hospitality | 2019 |
| Chilton Meadows Day Nursery Limited | Education | 2001 |
| Chimney Craft Ltd | Construction | 2026 |
| Chiswick Electrical Solutions Ltd | Construction | 2022 |
| Chokar Group Ltd | Professional & scientific | 2020 |
| Chopsy Holdings Ltd. | Financial services | 2020 |
| Chopsy Productions Ltd | Extraterritorial | 2012 |
| Chris Curry Plumbing Limited | Construction | 2021 |
| Christine Schick Ltd. | Health & social care | 2015 |
| Christopher Killeen Logistics Ltd | Transport & logistics | 2025 |
| City Building and Joinery Limited | Manufacturing | 2020 |
| CJS Podiatry Limited | Financial services | 2024 |
| Ckt+Prop Limited | Real estate | 2025 |
| Cladcliffe Ltd | Construction | 2020 |
| Clark Pharma Limited | Administrative & support | 2017 |
| Cleanrooms (Northern) Limited | Construction | 2023 |
| Clear Data Marketing Ltd | Administrative & support | 2020 |
| Clearview Windows (North East) Limited | Construction | 1991 |
| CLG Properties Ltd | Real estate | 2025 |
| Clockwork Developments Limited | Real estate | 2004 |
| Coastal Comforts Ltd | Real estate | 2025 |
| Cobalt Construction NE Ltd | Manufacturing | 2007 |
| Cobalt Facility Management Ltd | Construction | 2024 |
| Cobalt Plant Hire ( Durham ) Ltd | Administrative & support | 2023 |
| Colin Coates Consultancy Limited | Professional & scientific | 1986 |
| Colin Foster Associates Limited | Professional & scientific | 2020 |
| Colquhoun PM Services Ltd | Construction | 2023 |
| Community Assistance NE Ltd | Wholesale & retail | 2020 |
| Condor Contracts Training Ltd | Construction | 2018 |
| Connect Facilities Limited | Administrative & support | 2019 |
| Connor Capital Limited | Financial services | 2023 |
| Connor Pritchard TM Ltd | Construction | 2022 |
| Constructing Excellence in the North East Limited | Administrative & support | 2003 |
| Continental Delicatessen Ltd | Hospitality | 2018 |
| Continuous NE Ltd | Professional & scientific | 2024 |
| Conway Christie North Ltd | Real estate | 2024 |
| Core Pharma Limited | Wholesale & retail | 2009 |