| Bylo Ltd | Information & communication | 2026 |
| Bytomic Distribution Limited | Wholesale & retail | 1999 |
| C & a Invest Tech Ltd | Information & communication | 2022 |
| C & R Management Limited | Real estate | 2026 |
| C & T Creative Ltd | Arts & recreation | 2026 |
| C & W Consultants (Banbury) Ltd | Professional & scientific | 2011 |
| C M Coleman Ltd | Administrative & support | 2012 |
| C Medden Limited | Other services | 2018 |
| C Payne Consultancy Limited | Hospitality | 2013 |
| C&M Publishing Limited | Information & communication | 2013 |
| C.K. Jansz Limited | Arts & recreation | 2010 |
| C10 Distributions Limited | Wholesale & retail | 2025 |
| Cactai Limited | Information & communication | 2026 |
| Calgary Enterprise Ltd | Administrative & support | 2002 |
| Caltag Medsystems Limited | Manufacturing | 2001 |
| Caltag Medsystems Trustee Limited | Extraterritorial | 2025 |
| Cambridge River Tours Ltd | Wholesale & retail | 2017 |
| Cameraman-Online Limited | Professional & scientific | 2011 |
| CAMERAS4TV Limited | Information & communication | 2001 |
| Cameron Bookshops Limited | Wholesale & retail | 2015 |
| Camtek Development Ltd | Professional & scientific | 2019 |
| CAN Packaging Services Ltd | Professional & scientific | 2026 |
| Canada House Limited | Financial services | 2019 |
| Canine Film Services Limited | Information & communication | 2002 |
| Canola Solutions Ltd | Professional & scientific | 2010 |
| Canopy Fitter Limited | Construction | 2025 |
| Capetonian Property Management Ltd | Real estate | 2023 |
| Capital Corporate Finance Limited | Professional & scientific | 1992 |
| Cara Accounting Ltd | Professional & scientific | 2025 |
| Carbon Art 45 Limited | Arts & recreation | 2012 |
| Carbon Grass Limited | Construction | 2017 |
| Care Dial Group Ltd | Financial services | 2026 |
| Care Hair UK Ltd | Other services | 2024 |
| Care Navigators Ltd | Public administration | 2021 |
| Carisbrooke Management Services Limited | Households | 2008 |
| Carnarvon Road Property Management Limited | Households | 2010 |
| Carnsgill Limited | Professional & scientific | 1977 |
| Carpet Finishers Limited | Administrative & support | 2012 |
| Carrot Finance Limited | Financial services | 2026 |
| Carswell Engineering Limited | Professional & scientific | 2025 |
| Carters Gate Property Investment Ltd | Real estate | 2025 |
| Carville Property Developments Limited | Construction | 2024 |
| Cashflow Bridge Limited | Financial services | 2015 |
| Castle Fields Farm Limited | Agriculture & fishing | 2025 |
| Castle Fields Holdings Limited | Agriculture & fishing | 2025 |
| Catch Development Limited | Administrative & support | 2014 |
| Cavern Blue Limited | Information & communication | 2015 |
| CB Club Consulting Ltd | Professional & scientific | 2024 |
| CBE Global Limited | Information & communication | 2009 |
| Cbit Enterprises Ltd | Real estate | 2013 |
| Cbit Property Ltd | Real estate | 2015 |
| CE Gibson Consulting Limited | Professional & scientific | 2014 |
| Cecil's Yard Management Limited | Households | 2006 |
| Celia Forner Limited | Wholesale & retail | 1998 |
| Celtic Court Management Limited | Real estate | 1989 |
| CEM Microwave Technology Limited | Professional & scientific | 1989 |
| Central Effects Ltd | Manufacturing | 2024 |
| Centroheating Limited | Construction | 2026 |
| Cgib Holdings Limited | Financial services | 2022 |
| CGL886 Limited | Arts & recreation | 2013 |
| Chackmore Limited | Construction | 2013 |
| Champ Spares Revival Limited | Public administration | 2012 |
| Chandell Properties Ltd | Real estate | 2024 |
| Chandler RAY Limited | Professional & scientific | 2013 |
| Chandos Ltd | Real estate | 2018 |
| Chaplin and Chaplin Holdings Ltd | Financial services | 2017 |
| Chardan IT Services Ltd | Information & communication | 2021 |
| Charged AI Ltd | Information & communication | 2024 |
| Chariteer Ltd | Information & communication | 2016 |
| Charmasson Management Consultants Limited | Professional & scientific | 2009 |
| Cherwell Vans Ltd | Wholesale & retail | 2016 |
| Children and Young People Open Voice Support Ltd | Health & social care | 2022 |
| Chiltern Training Services Ltd | Education | 2024 |
| CHINACOTTAGE26 Limited | Hospitality | 2026 |
| Chindit Ethos Limited | Professional & scientific | 2025 |
| Christabel Jones Ltd | Health & social care | 2024 |
| Christabel’S Brownies Ltd | Wholesale & retail | 2024 |
| Christian LE Fevre Classics Ltd | Wholesale & retail | 2022 |
| Christopher Kane Limited | Wholesale & retail | 2023 |
| Church Street Brewery Ltd | Manufacturing | 2021 |
| Church View Buildings Limited | Construction | 2016 |
| Churchill Motorcycles Limited | Wholesale & retail | 2018 |
| Churchill Motors (Potterspury) Limited | Wholesale & retail | 2010 |
| Churchill Stone Limited | Administrative & support | 2010 |
| CK Foods Limited | Hospitality | 2021 |
| Cktk Studio Ltd | Professional & scientific | 2023 |
| Claremont Close Winslow (Management) Limited | Real estate | 2016 |
| Clarity CMC Pharma Solutions Ltd | Professional & scientific | 2025 |
| Claydon Auctioneers Ltd | Wholesale & retail | 1999 |
| Claydon Consultants Ltd | Professional & scientific | 2011 |
| Claydon Flooring Ltd | Construction | 2021 |
| Claydon Hill Farm Management Co Limited | Households | 2005 |
| Claydon Solar Action Group | Other services | 2024 |
| Clayton Media Services Limited | Information & communication | 2014 |
| Clear Voice Advocacy Ltd | Health & social care | 2026 |
| Clearhorizon IT Ltd | Information & communication | 2025 |
| Clearlink Roller Shutters Limited | Manufacturing | 2006 |
| Clearly Speaking Limited | Health & social care | 2005 |
| Cleft Wood Company Ltd | Manufacturing | 2012 |
| Clever Crowd Tech Ltd | Information & communication | 2023 |