| Cosy Clean NE Ltd | Administrative & support | 2026 |
| Cosy Dove Limited | Hospitality | 2015 |
| Cosy News Limited | Wholesale & retail | 2008 |
| Cosyjoes (Sheffield) Limited | Hospitality | 2025 |
| Cosytherm Limited | Wholesale & retail | 1985 |
| Counsel of Neurodivergent Minds Ltd | Health & social care | 2026 |
| Count on US Stocktakers Limited | Administrative & support | 2005 |
| Counterfeit Group Ltd | Arts & recreation | 2015 |
| Counting Bulb Limited | Real estate | 2024 |
| Country & Coyotes Ltd | Hospitality | 2025 |
| Countrywide Commercial Limited | Administrative & support | 2014 |
| Countrywide Property Group Limited | Financial services | 2021 |
| County Durham Fabrications Limited | Manufacturing | 2015 |
| County Durham Utilities Ltd | Construction | 2016 |
| County Life Homes Limited | Construction | 1991 |
| Countylife (Brunton) Limited | Construction | 2021 |
| Countylife Bamburgh Limited | Construction | 2009 |
| Countylife Beadnell Limited | Construction | 2019 |
| Countylife Corbridge Limited | Construction | 2009 |
| Countylife Northumbria Limited | Construction | 2019 |
| Countylife Streetgate Ltd | Construction | 2022 |
| Countylife Thrunton Limited | Construction | 2023 |
| Courtyard Developments (Newcastle) Limited | Real estate | 1990 |
| Covered Events Ltd | Administrative & support | 2018 |
| Covion Limited | Real estate | 2000 |
| Cowell's Garden Centre Limited | Wholesale & retail | 2013 |
| Cowgate Minimarket Ltd | Wholesale & retail | 2018 |
| Cowgate Pizza Limited | Hospitality | 2019 |
| Cowhide Digital Ltd | Information & communication | 2021 |
| Cowie Group Ltd | Other services | 2021 |
| Cowley Road Services Ltd | Transport & logistics | 2020 |
| Cowrily Ltd | Information & communication | 2026 |
| COX Engines Limited | Professional & scientific | 1993 |
| Coyote Run Limited | Other services | 2016 |
| Coza Nostra Ltd | Hospitality | 2024 |
| Cozy Bed’Z Limited | Wholesale & retail | 2025 |
| Cozy Point Ltd | Real estate | 2025 |
| Cozyloom Ltd | Wholesale & retail | 2025 |
| CP Cabling Contracts Ltd | Construction | 2025 |
| CP Computer and Phone Ltd | Other services | 2025 |
| CP Hvac Solutions Ltd | Construction | 2014 |
| CPA Security Ltd | Administrative & support | 2024 |
| Cpbtrade Ltd | Wholesale & retail | 2024 |
| CPD Services Ltd | Transport & logistics | 2020 |
| Cpdm Holdings Limited | Other services | 2019 |
| CPH Property Services Ltd | Real estate | 2018 |
| Cpig Developments Limited | Construction | 2025 |
| CPM (Newcastle) Ltd | Households | 2018 |
| CPM Metals Ltd | Wholesale & retail | 2018 |
| CPM Ortho 1 Limited | Health & social care | 2021 |
| CPS Medical Ltd | Health & social care | 2004 |
| CPS Valve Solutions Ltd | Wholesale & retail | 2024 |
| CPT Science Ltd | Manufacturing | 2004 |
| CR Digital Limited | Professional & scientific | 2025 |
| CR Utilities Ltd | Construction | 2018 |
| Cr&Jr Ltd | Financial services | 2021 |
| Crabbish Newcastle Ltd | Hospitality | 2026 |
| Crable Ltd | Manufacturing | 2018 |
| Crable Services Limited | Manufacturing | 2018 |
| Craft Carlisle Limited | Hospitality | 2025 |
| Crafted Projects Ltd | Hospitality | 1982 |
| Crafttown Limited | Other services | 2025 |
| Cragside Gardens (Rothbury) Management Company Limited | Households | 2017 |
| Craig Astley Projects Limited | Arts & recreation | 2019 |
| Craig Cottage Limited | Hospitality | 2021 |
| Craig Currie Logistics Ltd | Transport & logistics | 2025 |
| Craigower Investments Ltd | Real estate | 2017 |
| Crake & Mallon | Professional & scientific | 2019 |
| Cramli Pizza Ltd | Hospitality | 2019 |
| Cramlington Body Repairs Limited | Wholesale & retail | 2020 |
| Cramlington Carpets Ltd | Construction | 2025 |
| Cramlington Components Limited | Manufacturing | 1978 |
| Cramlirose Ltd | Hospitality | 2022 |
| Cranbourne Estates Limited | Construction | 2002 |
| Craster Harbour Ltd | Wholesale & retail | 2021 |
| Crathorne Properties Limited | Real estate | 2001 |
| Cratsol Ltd | Information & communication | 2017 |
| Craven Templar Holdings Limited | Wholesale & retail | 1946 |
| Cravens Limited | Professional & scientific | 1988 |
| Crawford Construction Ltd | Construction | 2015 |
| Crazy Campers Campervan Hire Limited | Administrative & support | 2021 |
| CRC Newcastle Ltd | Real estate | 2009 |
| CRD Enterprises Limited | Hospitality | 2024 |
| CRE8 CAD Solutions Ltd | Professional & scientific | 2023 |
| CRE8.APP Ltd | Information & communication | 2021 |
| Cream Curls Limited | Hospitality | 2025 |
| Creation Cloud Limited | Wholesale & retail | 2020 |
| Creation House Healthcare Limited | Health & social care | 2020 |
| CREATIONS4NATIONS Ltd | Health & social care | 2025 |
| Creative Agile Partners Limited | Information & communication | 2013 |
| Creative Concrete Drives Limited | Construction | 2021 |
| Creative Craniums Ltd | Wholesale & retail | 2012 |
| Creative Heritage Studios CIC | Manufacturing | 2020 |
| Creative Homes 4 YOU Ltd | Construction | 2019 |
| Creative Minds and Thoughts Ltd | Wholesale & retail | 2023 |
| Creative Motion (CM) 3 Media Group Limited | Information & communication | 2026 |
| Creative Security Dynamics Ltd | Administrative & support | 2011 |
| Creative Sight Ltd | Professional & scientific | 2025 |
| Creative Square Ltd | Professional & scientific | 2024 |
| Creative Streak Design LLP | | 2017 |