| Colour 'N' Curls Limited | Other services | 2022 |
| Colouricity Ltd | Wholesale & retail | 2018 |
| Colourmagic Auto Repair Shop Ltd | Wholesale & retail | 2025 |
| Colwyns Commercial Ltd | Real estate | 2023 |
| Colwyns Properties Ltd | Real estate | 2020 |
| Combine Consulting Ltd | Professional & scientific | 2025 |
| Comengage Limited | Professional & scientific | 2023 |
| Comfort CAB Limited | Transport & logistics | 2025 |
| Comfort Home Care Ltd | Health & social care | 2016 |
| Comfy Tickets Limited | Administrative & support | 2017 |
| Comgensys Ltd | Information & communication | 2012 |
| Commercial Occupational Health Services Limited | Health & social care | 2013 |
| Commercial Sanitising Specialists Ltd | Administrative & support | 2020 |
| Commercial Scrap Solutions Ltd | Water & waste | 2020 |
| Commercial Services Group Ltd | Extraterritorial | 2025 |
| Commercial Site Services Ltd | Extraterritorial | 2025 |
| Commercial Transport Export Limited | Wholesale & retail | 1998 |
| Commercial Waste Clearance Ltd | Water & waste | 2025 |
| Commero Ltd | Wholesale & retail | 2026 |
| Common Edge (PTY) Ltd | Mining & quarrying | 2021 |
| Commonsense Initiative Ltd | Education | 2017 |
| Communities Together | Information & communication | 2007 |
| Community Activators CIC | Health & social care | 2025 |
| Community DEN Ltd | Information & communication | 2024 |
| Community Education Skills 4 Life Ltd | Education | 2015 |
| Community Paradigm CIC | Health & social care | 2024 |
| Community Places Limited | Health & social care | 2004 |
| Community Platform Together CIC | Education | 2026 |
| Community Rail Network | Transport & logistics | 2001 |
| Community Skills Centre CIC | Education | 2023 |
| Comp-Bio Products Limited | Wholesale & retail | 2006 |
| Compass Driver Training Ltd | Education | 2022 |
| Compassion Support Ltd | Health & social care | 2023 |
| Competent Adviser Limited | Information & communication | 2003 |
| Competent Adviser Training Limited | Education | 2013 |
| Competent Asphalt Co. Limited | Construction | 1972 |
| Complete Asbestos Surveys Limited | Administrative & support | 2020 |
| Complete Community Care Yorkshire Limited | Wholesale & retail | 2012 |
| Complete FAN Maintenance Limited | Construction | 1988 |
| Complete Prescribing Solutions Ltd | Health & social care | 2018 |
| Complete Tree Solutions Ltd | Agriculture & fishing | 2025 |
| Complexfbaseller Ltd | Wholesale & retail | 2023 |
| Compliance Control Consultancy Limited | Professional & scientific | 2017 |
| Compliance Oversight Services Limited | Public administration | 2023 |
| Compoder Limited | Wholesale & retail | 2012 |
| Component Centre Ltd | Wholesale & retail | 2026 |
| Composite Colour Ltd | Manufacturing | 2021 |
| Composite Doors Yorkshire Limited | Extraterritorial | 2012 |
| Composite Windows Yorkshire Limited | Extraterritorial | 2015 |
| Computer Rock Ltd | Information & communication | 2015 |
| Computers & Repairs Ltd | Wholesale & retail | 2025 |
| Concept Construction (Yorkshire) Ltd | Construction | 2017 |
| Concept Drilling Services Limited | Construction | 2004 |
| Concept Esthetics @ Lindley Ltd | Other services | 2025 |
| Concept Locum Services Ltd | Health & social care | 2022 |
| Concept Medicine Ltd | Health & social care | 2014 |
| CONCEPT2ENGINEERING Ltd | Administrative & support | 2010 |
| Conceptvise Ltd | Wholesale & retail | 2024 |
| Concise Distribution Solutions Limited | Transport & logistics | 2012 |
| Concorde 002 Limited | Real estate | 2018 |
| Concorde Property Investments Ltd | Real estate | 2024 |
| Concordia Health and Social Care Limited | Health & social care | 2021 |
| Concrete Grinding Limited | Construction | 1996 |
| Concrete Operations Services Ltd | Construction | 2023 |
| Condor Counselling Ltd | Health & social care | 2017 |
| Confex Confectionery Limited | Wholesale & retail | 2013 |
| Confidence With SJ Ltd | Education | 2025 |
| Connah Construction Ltd | Construction | 2013 |
| Connah Construction One Ltd | Construction | 2021 |
| Connah Investments Ltd | Real estate | 2015 |
| Connah Investments One Ltd | Real estate | 2025 |
| Connaught Fold Property Company Limited | Households | 1997 |
| Connect Business Centre Ltd | Real estate | 2018 |
| Connect Day Services Ltd | Health & social care | 2016 |
| Connect QX Ltd | Wholesale & retail | 2021 |
| Connect Study Centre Ltd | Education | 2017 |
| Connect UK Study Ltd | Professional & scientific | 2017 |
| Connect Yoga and Wellness Ltd | Health & social care | 2018 |
| Connecta Beauty Limited | Wholesale & retail | 2026 |
| Connecting Worlds Globally Ltd | Wholesale & retail | 2022 |
| Connexions Phones Ltd | Wholesale & retail | 2008 |
| Connolly (UK) Ltd | Construction | 2012 |
| Connolly UK Homes Ltd | Real estate | 2024 |
| Conqueror Associates Limited | | 1991 |
| Conqueror Security Ltd | Administrative & support | 2026 |
| Consciente Ltd | Information & communication | 2023 |
| Conscious Visions Limited | Wholesale & retail | 1997 |
| Conscious Youth C.I.C. | Education | 2016 |
| Conserv Engineering Services Ltd | Professional & scientific | 2012 |
| Consider Energy Limited | Professional & scientific | 2015 |
| Considered Jewellery Ltd | Wholesale & retail | 2021 |
| Consolidis Limited | Wholesale & retail | 2026 |
| Constant Healthcare Ltd | Health & social care | 2016 |
| Construction DC Ltd | Construction | 2025 |
| Consult 3A Ltd | Professional & scientific | 2013 |
| Consult Packaging Limited | Professional & scientific | 2021 |
| Consulting Advantage Ltd | Professional & scientific | 2014 |
| Consulting With Purpose Limited | Professional & scientific | 2008 |
| Contact Gearing Limited | Professional & scientific | 2012 |
| Container People Storage Ltd | Transport & logistics | 2024 |