| Class Electrical (UK) Limited | Construction | 2011 |
| Classic Chambers Limited | Wholesale & retail | 2012 |
| Classic Cooker Services Ltd | Other services | 2018 |
| Classic Cosmetics Ltd | Other services | 2022 |
| Classic Volks Limited | Wholesale & retail | 2023 |
| Classone Systems Limited | Professional & scientific | 2019 |
| Classroom Computing Ltd | Education | 2021 |
| Claudius Consulting Limited | Professional & scientific | 2007 |
| Claxton Grange Cottages Management Company Limited | Households | 2022 |
| Claxton Grange Venture LLP | | 2018 |
| Clayfield Construction Limited | Wholesale & retail | 1966 |
| Clayfield Holidays (CFH) Ltd | Hospitality | 2021 |
| Clayfox Associates Limited | Information & communication | 1989 |
| Claypenny Consulting Limited | Financial services | 2016 |
| Clean Account Solutions Ltd | Information & communication | 2024 |
| Clean Eats Ltd | Wholesale & retail | 2015 |
| Clean Life Beauty Ltd | Wholesale & retail | 2024 |
| Clean-Draw Engineering Limited | Professional & scientific | 2025 |
| Cleancore UK Ltd | Construction | 2018 |
| Cleaning Shine Ltd | Administrative & support | 2026 |
| Cleanroom Consulting Limited | Professional & scientific | 2003 |
| Cleanse&Shine Ltd | Administrative & support | 2025 |
| Clear Horizons York Ltd | Professional & scientific | 2024 |
| Clear Shine Cleaning Enterprises Limited | Administrative & support | 2020 |
| Clearly Apartments Ltd | Real estate | 2005 |
| Clearly Consulting & Training Limited | Professional & scientific | 2008 |
| Cleartech Construction Cleaning Services Limited | Other services | 2016 |
| Cleartech Consulting Limited | Information & communication | 2003 |
| Clearwave Enterprise Solutions Limited | Information & communication | 2011 |
| Clegram Investments Limited | Real estate | 2024 |
| Clegram Real Estate Limited | Real estate | 2024 |
| Clelland Consulting Ltd | Information & communication | 2015 |
| Clement Leadership Development Ltd | Professional & scientific | 2022 |
| Clementhorpe (York) Management Company Limited | Households | 1992 |
| Clementhorpe Ltd | Real estate | 2020 |
| Clements Hall Trust | Arts & recreation | 2000 |
| Clemit Services & Supplies Ltd | Wholesale & retail | 2021 |
| Clennan Properties Limited | Real estate | 2017 |
| Cleopamper Ltd | Manufacturing | 2020 |
| Clervaux Trust Holdings | Education | 1999 |
| Cleveland View Management Company Limited | Households | 2005 |
| Cleverdotsolutions Limited | Professional & scientific | 2001 |
| Client Profits Limited | Construction | 2011 |
| Cliff Harrison Developments Limited | Construction | 2013 |
| Cliff Stud Limited | Arts & recreation | 2016 |
| Clifton 2022 Barber Ltd | Other services | 2026 |
| Clifton 25 Ltd | Hospitality | 2025 |
| Clifton Bingo Club Limited | Arts & recreation | 1936 |
| Clifton Bridge Hotel Limited | Hospitality | 2013 |
| Clifton Garth Management Co. Ltd | Administrative & support | 2008 |
| Clifton Green Management Company Limited | Real estate | 2006 |
| Clifton Moor Business Village (York) Limited | Real estate | 1988 |
| Clifton Moor Developments Ltd | Construction | 2025 |
| Clifton Moor Pre-School | Education | 2010 |
| Clima Group Ltd | Construction | 2025 |
| Climate Change DUE Diligence Group Ltd | Professional & scientific | 2023 |
| Climate Heating Services Limited | Construction | 2025 |
| Climate Smart Farming Ltd | Administrative & support | 2016 |
| Clinical and Evidential Storage Ltd. | Administrative & support | 2013 |
| Clinical Technologies (York) Ltd | Construction | 2016 |
| Cliniscape Ltd | Information & communication | 2021 |
| Clipperbits Ltd | Wholesale & retail | 2024 |
| CLK Properties Limited | Real estate | 2015 |
| Clockhouse Partnership Limited | Hospitality | 2015 |
| Cloisters Close (York) Management Company Limited | Households | 1984 |
| Closs Consulting Limited | Professional & scientific | 2009 |
| Cloud Cocina Ltd | Hospitality | 2025 |
| Cloud Creativity Limited | Information & communication | 2012 |
| Cloud Nine Capital Holdings Limited | Financial services | 2026 |
| Cloud Optics Limited | Information & communication | 2014 |
| Cloud Ready Ltd | Information & communication | 2011 |
| Cloudbreak Yacht Media Ltd | Information & communication | 2024 |
| Cloudmatica Limited | Information & communication | 2010 |
| Clova Tax Limited | Professional & scientific | 2026 |
| Clover Chase (Lingwood) Residents Management Company Limited | Households | 2014 |
| Cloverlea Gardens (Kingswood) Management Company Limited | Households | 2025 |
| Clown Space CIC | Arts & recreation | 2024 |
| Club Class Cars (York) Limited | Wholesale & retail | 2017 |
| Club Class Entertainment Ltd | Professional & scientific | 2012 |
| Club Class Property Ltd | Real estate | 2023 |
| Clubhouse Mobile Mini Golf Ltd | Arts & recreation | 2018 |
| Clustero Ltd | Information & communication | 2022 |
| Clx.Media Ltd | Professional & scientific | 2025 |
| Clydesdale Consulting Ltd | Professional & scientific | 2010 |
| Clzens Ltd | Wholesale & retail | 2024 |
| CM Marketing Solutions Limited | Professional & scientific | 2020 |
| CMA Group Holdings Ltd | Professional & scientific | 2022 |
| CMB Computers Ltd | Wholesale & retail | 2014 |
| CMD Trading Ltd | Wholesale & retail | 2022 |
| CMG Sales Ltd | Wholesale & retail | 2017 |
| CMM Wealth Management Ltd | Financial services | 2025 |
| CN Solutions Private Ltd | Construction | 2026 |
| CNK Group Limited | Other services | 2018 |
| Cnnd Ltd | Information & communication | 2024 |
| Co. LA TEK Limited | Administrative & support | 2006 |
| Coach and Stables Ltd | Wholesale & retail | 2019 |
| Coach for My Life Limited | Professional & scientific | 2020 |
| Coach Manager Systems Limited | Professional & scientific | 1991 |
| Coach PW Consulting Limited | Education | 2022 |
| Coachman's Court Limited | Real estate | 2015 |