| Cambridge Coachworks Services Ltd | Wholesale & retail | 2016 |
| Cardiff Road MOT and Service Centre Ltd | Wholesale & retail | 2021 |
| Carlyon House Management Company Limited | Households | 2016 |
| Carma Drivers Ltd | Education | 2025 |
| Carrington Property Trading Ltd | Real estate | 2025 |
| Carva Ltd | Wholesale & retail | 2026 |
| Casamiatech UK Ltd | Construction | 2025 |
| Caselli Smith Ltd | Households | 2017 |
| Cassidy Crew Ltd | Hospitality | 2022 |
| Catavault Ltd | Information & communication | 2022 |
| CC Counselling and Art Therapy CIC | Health & social care | 2025 |
| Ceallaigh Group Limited | Professional & scientific | 2009 |
| Cedar House (SL6) RTM Company Limited | Households | 2024 |
| Chacarera Ltd | Hospitality | 2026 |
| Chaos Collective Gaming Limited | Arts & recreation | 2025 |
| Chapman Macdonald Ltd | Professional & scientific | 2020 |
| Charles DE WET Ltd | Professional & scientific | 2016 |
| Chase Consulting Services Ltd | Administrative & support | 2022 |
| Cherry Local Express Limited | Wholesale & retail | 2020 |
| Chris Bayliss Propservices Limited | Information & communication | 2022 |
| Christie Kinge Group Ltd | Professional & scientific | 2023 |
| Church Street (Crowthorne) Management Limited | Households | 2013 |
| City Square London Limited | Financial services | 2001 |
| CKL Bucks Limited | Information & communication | 2011 |
| Claire Harvey Foundation C.I.C. | Health & social care | 2022 |
| Clare Court (Wokingham) Limited | Households | 1972 |
| Clarke&Co Motor Group Ltd | Wholesale & retail | 2024 |
| Clarke-Morris Investments Ltd | Real estate | 2021 |
| Claudio Altini & Associates Limited | Professional & scientific | 2020 |
| Claydon Court (Caversham) Management Company Limited | Households | 1984 |
| Clearwater Casino Consultancy Limited | Arts & recreation | 1999 |
| CLG Consulting Partners Limited | Administrative & support | 2015 |
| Clic Healthtech Ltd | Information & communication | 2025 |
| Clipco Designs Ltd | Wholesale & retail | 2021 |
| Clipper International Limited | Other services | 1993 |
| Clipper Marketing Services Limited | Transport & logistics | 1991 |
| Co.Lab Studio Group Ltd | Real estate | 2025 |
| Code Indigo Limited | Information & communication | 2004 |
| Cognetic Flow Ltd | Information & communication | 2023 |
| Coherence Consultancy Ltd | Administrative & support | 2023 |
| Collins Recruitment Limited | Administrative & support | 2022 |
| Comast Consultancy Limited | Professional & scientific | 2013 |
| Condon Services Limited | Health & social care | 2008 |
| Conexa Holdings Ltd | Professional & scientific | 2022 |
| Conexa Tech Solutions Ltd | Administrative & support | 2020 |
| Conexuspro Ltd | Administrative & support | 2024 |
| Connection Project Management Services Limited | Professional & scientific | 2017 |
| Consultlink UK Limited | Professional & scientific | 2020 |
| Continental Comestibles Limited | Real estate | 1936 |
| Conto Limited | Information & communication | 2007 |
| Cools Agriscience Consultancy Limited | Professional & scientific | 2022 |
| Copenhagen Mews RTM Company Limited | Households | 2012 |
| Coraleen Skincare Products Ltd | Manufacturing | 2019 |
| Corley Consulting Limited | Professional & scientific | 2017 |
| Corridor Creations Ltd | Professional & scientific | 2025 |
| Cosidero Limited | Professional & scientific | 2017 |
| Cosmonaut Holdings Ltd | Real estate | 2016 |
| Cosnetics Software Limited | Information & communication | 2022 |
| Countback Limited | Construction | 1986 |
| County Care Academy Ltd | Education | 2021 |
| County Carers Limited | Health & social care | 2013 |
| County Cleaning Group Ltd | Administrative & support | 2016 |
| Cranbourne Hall Management Company Limited | Households | 2008 |
| Creation DUB Ltd | Professional & scientific | 2025 |
| Creative 108 Ltd | Professional & scientific | 2023 |
| Creative Craft Studio Ltd | Other services | 2026 |
| Creative Project Services Limited | Construction | 2009 |
| Crestwater Ltd | | 2023 |
| Croeso Management Company Limited | Households | 2019 |
| Crowdean Limited | Construction | 2012 |
| Crown Green Management Company Limited | Households | 1989 |
| Crowthorne Consulting Limited | Professional & scientific | 2022 |
| Crowthorne Electrical Services Limited | Construction | 2007 |
| Crowthorne Hopezone | Other services | 2011 |
| Crowthorne Restaurants Limited | Hospitality | 2026 |
| Crowthorne Roofing Ltd | Construction | 2018 |
| Crowthorne Rugby Football Club Limited | Arts & recreation | 2022 |
| Crowthorne Service Centre Limited | Wholesale & retail | 2012 |
| Crowthorne Spice Ltd | Hospitality | 2020 |
| Crowthorne Technology Ltd | Information & communication | 2017 |
| Crucible Group Ltd | Arts & recreation | 2021 |
| Crucible Sports Limited | Arts & recreation | 2010 |
| Cucugates Ltd | Health & social care | 2025 |
| Cuisenaire Company Limited(The) | Wholesale & retail | 1963 |
| Cusfab Ltd | Construction | 2019 |
| Custom Curtains (Richmond) Limited | Wholesale & retail | 2024 |
| Cwca Ltd | Education | 2026 |
| D&D Construction Limited | Construction | 2025 |
| D&S Enterprise Holdings Ltd | Real estate | 2019 |
| D.A.M. Services Limited | Administrative & support | 1997 |
| DAM Films Ltd | Information & communication | 2018 |
| Data Systems (Computers) Limited | Information & communication | 1987 |
| Datavue Ltd | Information & communication | 2024 |
| David Fitzgerald Building Services Limited | Construction | 2001 |
| DCD Global Limited | Professional & scientific | 2023 |
| Deaf Reach UK Limited | Health & social care | 2015 |
| Deane-Drummond Consultancy Ltd | Professional & scientific | 2019 |
| Dearers Homes Limited | Real estate | 2019 |
| Deckerland Limited | Construction | 1966 |
| Deeaim Limited | Information & communication | 2014 |