| Business Accountancy and Payroll Consultants Limited | Professional & scientific | 2018 |
| Buy & Save (GB) Ltd. | Other services | 2018 |
| Buy From US Autopark Limited | Wholesale & retail | 2012 |
| Buy From US Enterprise Centre Limited | Construction | 2009 |
| BVD Services Limited | Professional & scientific | 2019 |
| BW Brickworks NE Ltd | Construction | 2022 |
| BW95 Ltd | Financial services | 2024 |
| BY Jessica Ltd | Other services | 2020 |
| Byers Garth Management Company Limited | Households | 2002 |
| C & D Deliveries Ltd | Transport & logistics | 2020 |
| C & H Fabrication Ltd | Manufacturing | 2024 |
| C & P Catering Company Limited | Hospitality | 2023 |
| C & P Northern Company Ltd | Hospitality | 2017 |
| C & P Ryder Ltd | Construction | 2023 |
| C & R Restaurant Ltd | Hospitality | 2025 |
| C Adamson Services Ltd | Construction | 2019 |
| C and C Campbell Limited | Construction | 2022 |
| C Croxford Ltd | Information & communication | 2024 |
| C D Process Engineering Resources Ltd. | Professional & scientific | 2007 |
| C G Golden Valley Ltd | Hospitality | 2021 |
| C Grey Limited | Health & social care | 2002 |
| C J Office Installations Ltd | Construction | 2011 |
| C K & G Homes Limited | Real estate | 2020 |
| C P Bewley & Associates Limited | Other services | 1993 |
| C R Responsive Maintenance Limited | Construction | 2019 |
| C Robertson Groundworks Ltd | Construction | 2021 |
| C Thompson Ltd | Construction | 2021 |
| C Woolams Driveways Ltd | Construction | 2021 |
| C&C Groundworks/Construction Ltd | Construction | 2021 |
| C&L Construction (NE) Limited | Construction | 2016 |
| C&N Catering Crew Ltd | Hospitality | 2025 |
| C&P GAS Services Limited | Energy | 2018 |
| C&P Recruitment Group Limited | Administrative & support | 2017 |
| C-A-R G/W + Plant Ltd | Construction | 2022 |
| C-Lite Ltd | Information & communication | 2019 |
| C. a. Blackwell (Contracts) Limited | Construction | 1956 |
| C.A. Blackwell (Plant) Limited | Construction | 2001 |
| C.A. Blackwell Group Limited | Professional & scientific | 1960 |
| C.A.I International Ltd | Wholesale & retail | 2015 |
| C.A.P.O.W Consulting Limited | Professional & scientific | 2010 |
| C.D. Dormant Limited | Education | 2022 |
| C.D.S. Security Limited | Administrative & support | 1991 |
| C.J. Homes (North East) Limited | Real estate | 2018 |
| C.L.S.H Ltd | Extraterritorial | 2012 |
| C.O Car Repairs Ltd | Wholesale & retail | 2022 |
| CA & MC Company Limited | Real estate | 2019 |
| CAB Drivers Limited | Transport & logistics | 2020 |
| Cacdp | Education | 1998 |
| Caddy Shack Golf Limited | Arts & recreation | 2021 |
| Cade Media Limited | Information & communication | 2021 |
| Cafe 22 Ltd | Hospitality | 2025 |
| CAG Plot Limited | Construction | 2018 |
| Cahill Solutions Limited | Information & communication | 2013 |
| Cakepops ET AL Ltd | Hospitality | 2025 |
| Calarm Limited | Real estate | 2023 |
| Caledonian Environmental Levenmouth Treatment Services Limited | Water & waste | 2000 |
| Caledonian Environmental Services Holdings Limited | Professional & scientific | 2000 |
| Call Yourself an Artist CIC | Arts & recreation | 2023 |
| Callum George Taylor & Partners Limited | Agriculture & fishing | 2018 |
| Calm in East Durham CIC | Other services | 2019 |
| Caluja Limited | Hospitality | 2013 |
| Calvert Holding Company Limited | Real estate | 2004 |
| Calzini Holdings Limited | Financial services | 2023 |
| Camsent Limited | Professional & scientific | 2007 |
| Candama Investors Limited Partnership | | 2003 |
| Candat Stores Ltd | Wholesale & retail | 2020 |
| Candowe Ltd | Wholesale & retail | 2023 |
| Canlisoy Ltd | Wholesale & retail | 2025 |
| Canney Hill Management Company Limited | Households | 2014 |
| Canny Comps Limited | Arts & recreation | 2022 |
| Cantab Medical Limited | Health & social care | 2016 |
| Canterbury Kids Club Limited | Education | 2009 |
| Cape Reva Limited | Real estate | 2017 |
| Capital Corporate Risks Ltd | Financial services | 2023 |
| Captain Shrapnel Ltd | Wholesale & retail | 2011 |
| Car and Van Solutions Ltd | Administrative & support | 2017 |
| Car Construction (North East) Ltd | Construction | 2014 |
| Car Glass Assist UK Limited | Wholesale & retail | 2017 |
| Car Holdings Limited | Financial services | 2018 |
| Car-Tech Prestige Limited | Manufacturing | 2007 |
| Carbon Action Ltd | Water & waste | 2009 |
| Care and Protect UK Limited | Health & social care | 2017 |
| CARE2INSPIRE Limited | Other services | 2015 |
| Carntyne Care Home Limited | Health & social care | 2019 |
| Carrick Performance Development Ltd | Arts & recreation | 2025 |
| Carroballista Limited | Administrative & support | 2009 |
| Carrson Properties Ltd | Real estate | 2025 |
| Carrville Podiatry and Wellness Clinic Ltd | Health & social care | 2019 |
| Carter Haswell Properties Limited | Real estate | 2016 |
| Carter House Limited | Real estate | 2022 |
| Carthouse Cafe Ltd | Hospitality | 2025 |
| Cartman Electrical Engineers Limited | Manufacturing | 2025 |
| Cartmel Touring Park Limited | Hospitality | 2026 |
| CAS Transporters Limited | Transport & logistics | 2018 |
| Casa Installations Limited | Construction | 2022 |
| Cashmoneyestates Limited | Real estate | 2021 |
| Casino Hire UK Limited | Arts & recreation | 2026 |
| Cassop Building & Consultancy Ltd | Professional & scientific | 2024 |
| Cassop Inns Ltd | Hospitality | 2025 |
| Castle and Bailey Property Investments Ltd | Real estate | 2026 |