| Coldburn Holdings Ltd | Information & communication | 2024 |
| Coleford Services LP | | 2017 |
| Coleman James Ltd | Administrative & support | 2016 |
| Coleman's Haulage Limited | Transport & logistics | 2017 |
| Colin Smith Flooring Limited | Construction | 2025 |
| Collaboration Spirits Ltd | Manufacturing | 2023 |
| Collaborative Architecture Limited | Professional & scientific | 2020 |
| Collaborative Architecture Sports Limited | Professional & scientific | 2022 |
| Collaborative Design Limited | Professional & scientific | 2019 |
| Collateralevents Ltd | Arts & recreation | 2025 |
| Collation Ltd | Information & communication | 2023 |
| Collectify Ltd | Wholesale & retail | 2025 |
| Collective Beauty (NE) Ltd | Other services | 2026 |
| Collective Objective Ltd | Professional & scientific | 2015 |
| Collective Software Ltd | Information & communication | 2026 |
| Collective Wellness Ltd | Information & communication | 2025 |
| Colledge Trundle & Hall Limited | Construction | 1996 |
| College of Doctoral Studies (Dcuk) | Education | 2025 |
| Collier Construction North East Ltd | Construction | 2025 |
| Collier Gardens (Philadelphia) Management Company Limited | Real estate | 2025 |
| Collingwood Court (Ponteland) Management Company Limited | Real estate | 2002 |
| Collingwood Developments Limited | Construction | 2019 |
| Collingwood Express Ltd | Wholesale & retail | 2024 |
| Collingwood Legal Limited | Professional & scientific | 2012 |
| Collingwood Marquees Ltd | Arts & recreation | 2014 |
| Collingwood Mews Management Limited | Real estate | 2001 |
| Collingwood Sofas Ltd. | Manufacturing | 2015 |
| Collinsgreat Limited | Hospitality | 2023 |
| Collis Edison LLP | | 2008 |
| Collkarn Group Limited | Financial services | 2026 |
| Colloch Ltd | Real estate | 2024 |
| Colmil Plant and Equipment Company Limited | Wholesale & retail | 1956 |
| Colonial Buildings Bradford Limited | Households | 2004 |
| Colonnade RTM Company Limited | Households | 2023 |
| Colorhub Ltd | Wholesale & retail | 2025 |
| Colour Urban Design Limited | Professional & scientific | 2002 |
| Colourbox Concept Ltd | Construction | 2025 |
| Coloured Profile Systems Limited | Construction | 2005 |
| Colt Clothing Ltd | Wholesale & retail | 2019 |
| Columbia Grange (NO 1) Management Company Limited | Real estate | 1992 |
| Colville Creative Ltd | Professional & scientific | 2022 |
| Colvin Smith (Pipework) Limited | Manufacturing | 1960 |
| Combhill Farms Limited | Real estate | 1978 |
| Comedy Support ACT UK Ltd | Arts & recreation | 2014 |
| Comet Garage Doors (UK) Ltd | Manufacturing | 2024 |
| Comfort Kitchen NE Limited | Hospitality | 2025 |
| Comfort on Clean Ltd | Construction | 2025 |
| Comfortable Doctors Ltd | Health & social care | 2023 |
| Comfycare Massage&Physical Wellness AID Ltd | Transport & logistics | 2021 |
| Comit Network Limited | Information & communication | 1999 |
| Comlos Limited | Real estate | 1998 |
| Commerce Chambers Ltd | Real estate | 2015 |
| Commercial Estates and Developments Ltd | Real estate | 2023 |
| Commercial IC 1 Ltd | Real estate | 2024 |
| Commercial Marble and Tiles Limited | | 1927 |
| Commercial Property Finance Consultancy Limited | Financial services | 1999 |
| Commercial Property Loans Ltd | Construction | 2020 |
| Commercial Property Maintenance NE Ltd | Construction | 2021 |
| Commercial Property Surveys Limited | Households | 2005 |
| Committed Support Group Limited | Health & social care | 2025 |
| Committed Support Ltd | Administrative & support | 2025 |
| Commodity & Energy (Emoola) Ltd | Information & communication | 2026 |
| Common Room Trading Limited | Administrative & support | 2017 |
| Comms Consulting Services (TCS) Limited | Information & communication | 2012 |
| Community Bench Media Ltd | Professional & scientific | 2026 |
| Community Companies Limited | Professional & scientific | 2016 |
| Community Counselling Co-Operative C.I.C. | Health & social care | 2012 |
| Community Foundation North East | Health & social care | 1988 |
| Community Kids Club CIC | Health & social care | 2020 |
| Community Minibuses Limited | Water & waste | 2000 |
| Community Moves Limited | Health & social care | 2009 |
| Community Safety Q CIC | Education | 2024 |
| Community Training CIC | Education | 2024 |
| Community Transport | Water & waste | 1987 |
| Commvest House Ltd | Wholesale & retail | 2025 |
| Como VA Hospitality Ltd | Hospitality | 2026 |
| Comogolet Investments Limited | Real estate | 2024 |
| Comops Ltd | Professional & scientific | 2026 |
| Compact Plant Hire Ltd | Administrative & support | 2024 |
| Company Law Club Limited | Extraterritorial | 1999 |
| Company Law Solutions Group Limited | Professional & scientific | 2015 |
| Company Law Solutions Limited | Professional & scientific | 1992 |
| Company of Others | Arts & recreation | 2016 |
| Company Relocations Ltd | Hospitality | 2019 |
| Compare the Bathroom Limited | Wholesale & retail | 2010 |
| Compare to Share CIC | Energy | 2020 |
| Compass Property and Landscape Ltd | Construction | 2025 |
| Compass Royston Travel Limited | Transport & logistics | 1998 |
| Compassion Kadampa Meditation Centre Newcastle | Education | 1997 |
| Compassionate Energy CIC | Administrative & support | 2025 |
| Compensationpack Limited | Administrative & support | 2009 |
| Complement Consulting Ltd | Professional & scientific | 2021 |
| Complete Answers Limited | Real estate | 1998 |
| Complete Boundary Solutions Ltd | Construction | 2022 |
| Complete Building Solutions U K Limited | Construction | 2019 |
| Complete Christianity and Holy Ghost Power Ministry | Other services | 2021 |
| Complete Project Hub Ltd | Professional & scientific | 2025 |
| Complete Shredding Limited | Water & waste | 2022 |
| Complex Connexions Community Interest Company | Education | 2020 |
| Complisync Limited | Professional & scientific | 2024 |