| Bijoux Hair Limited | Other services | 2015 |
| Bill Quay Precision Engineering & Fabrications Ltd | Manufacturing | 2009 |
| Bill's Motorcycles Limited | Wholesale & retail | 2014 |
| BJA Instrumentation Ltd | Mining & quarrying | 2023 |
| Bjenkinson Ltd | Construction | 2022 |
| Blajen Projects Limited | Construction | 2014 |
| Blue Sky Thinking (UK) Limited | Administrative & support | 2013 |
| Blue Star Nine Services Limited | Construction | 2024 |
| Blueberry Caterers Limited | Hospitality | 2017 |
| Bluesail Services Ltd | Professional & scientific | 2025 |
| BOB Emery Bricklayer Limited | Construction | 2011 |
| Body Upgrade Ltd | Extraterritorial | 2023 |
| Boldon Health and Wellbeing CIC | Health & social care | 2017 |
| Bondchem Holdings Limited | Financial services | 2023 |
| Bondchem Limited | Manufacturing | 2008 |
| BONO56 Limited | Wholesale & retail | 2021 |
| Bradleyshackswind Ltd | Construction | 2026 |
| Breeze Academy Limited | Education | 2022 |
| Brufern Holdings Ltd | Financial services | 2022 |
| Brushed Beauty by Shireen Ltd | Other services | 2022 |
| Building Energy & Retrofit Ltd | Construction | 2023 |
| Buschra Khalil Holdings Ltd | Wholesale & retail | 2024 |
| Business Owner’S Strategic Partner Ltd | Professional & scientific | 2025 |
| C H Consultants Group Limited | Professional & scientific | 2021 |
| C J Transport Services (North East) Limited | Other services | 2016 |
| C&I Electrical Ltd | Construction | 2014 |
| C1E2L3 Holdings Ltd | Financial services | 2025 |
| C2 Drones Limited | Professional & scientific | 2024 |
| Cafe Obscura Ltd | Hospitality | 2021 |
| Caitmines Ltd | Wholesale & retail | 2020 |
| Calber Homes Ltd | Construction | 2023 |
| Calell Holdings Limited | Information & communication | 2022 |
| Callum Rooney Welding Services Limited | Other services | 2014 |
| Calvin FOX Limited | Construction | 2015 |
| Campus Connections Limited | Education | 2023 |
| Canadaenergy Ltd | Professional & scientific | 2022 |
| Canny Northern Media Ltd | Information & communication | 2022 |
| Castle Design Limited | Professional & scientific | 2024 |
| Cbso Holdings Ltd | Financial services | 2023 |
| CDM Recruitment Limited | Administrative & support | 2002 |
| CFM Offshore NE Ltd | Professional & scientific | 2020 |
| Chambers Chemist Limited | Wholesale & retail | 2019 |
| Chamops Ltd | Information & communication | 2024 |
| Chapel Street Piping Ltd | Professional & scientific | 2025 |
| Charles Mccain Barrister Limited | Professional & scientific | 2019 |
| Charley Brewis Investments Limited | Agriculture & fishing | 2021 |
| Chase Holmes Lettings Limited | Real estate | 2010 |
| Chase Holmes Sales Limited | Real estate | 2010 |
| Chemical Solutions NE Ltd | Wholesale & retail | 2026 |
| Cheripai Beauty Limited | Wholesale & retail | 2020 |
| Cherwell Electrical Services Limited | Extraterritorial | 1985 |
| Cherwell Mechanical Services Limited | Extraterritorial | 1982 |
| Chrisdaline Ltd | Construction | 2007 |
| Classic Plumbing and Heating Ltd | Construction | 2017 |
| Click NDT Limited | Professional & scientific | 2013 |
| Clubhouse and Guestbooth Limited | Professional & scientific | 2014 |
| Cmee Environmental Ltd | Administrative & support | 2025 |
| CN Power Solutions Ltd | Construction | 2025 |
| COMBAT96 Ltd | Arts & recreation | 2024 |
| Complete Power Solutions Limited | Real estate | 2014 |
| Conscience Coaching and Consulting Community Interest Company | Health & social care | 2024 |
| Consultiv Holdings Ltd | Financial services | 2019 |
| Consultiv Utilities Enterprise Limited | Other services | 2021 |
| Consultiv Utilities Limited | Other services | 2017 |
| Contractorspye Ltd | Administrative & support | 2023 |
| Contractorspye Solutions Ltd | Administrative & support | 2023 |
| Core Maintenance Group Limited | Construction | 2015 |
| Cottam Brush Ltd | Manufacturing | 1946 |
| Cottam Investments Limited | Real estate | 2010 |
| Court Leet (Kenilworth) Management Company Limited | Households | 1994 |
| CP Sales & Marketing Ltd | Other services | 2023 |
| CRA Lettings Ltd | Financial services | 2019 |
| Crawford Consulting Services Ltd | Professional & scientific | 2025 |
| CS Electrical (NE) Limited | Construction | 2026 |
| CS Removals and Storage Ltd | Transport & logistics | 2025 |
| Cultura Capo Ltd | Wholesale & retail | 2022 |
| Curly Girl Properties Ltd | Real estate | 2025 |
| Curtis Instruments (U.K.) Limited | Manufacturing | 1974 |
| Cyberram Consulting Ltd | Information & communication | 2025 |
| Cyberram Ltd | Information & communication | 2021 |
| D & D Ventilation Limited | Construction | 2018 |
| D W H Engineering Limited | Manufacturing | 1993 |
| D.Lupton Ltd | Other services | 2019 |
| D.S. Rescue & Recovery Specialists Ltd | Wholesale & retail | 2013 |
| D.S.L. GAS FIX Ltd | Energy | 2016 |
| Dalay Ltd | Public administration | 2020 |
| DAM Consultants Ltd | Construction | 2024 |
| DAN Mcalindon Construction Management Services Ltd | Professional & scientific | 2024 |
| Danellie Limited | Real estate | 2020 |
| Dazy Holdings Limited | Information & communication | 2018 |
| DCK Industrial Services Ltd | Administrative & support | 2025 |
| DCS Consultancy Ltd | Professional & scientific | 1999 |
| De-Lux Hebburn Hand Car Wash Ltd | Other services | 2023 |
| Dead Reel Films Ltd | Information & communication | 2018 |
| Dead-Quiet Ltd | Health & social care | 2015 |
| Dean Potts Construction Ltd | Construction | 2025 |
| Delta One Security Services Limited | Administrative & support | 1991 |
| DH Industrial Services Limited | Construction | 2014 |
| DH Property Management Holdings Ltd | Real estate | 2019 |
| DH Subsea Services Ltd | Mining & quarrying | 2026 |