| Carlton Vale Investment Company Limited | Financial services | 1954 |
| Carnarvon Consultants Limited | Administrative & support | 2011 |
| Carnival Travel Ltd | Administrative & support | 2014 |
| Caro CAN Limited | Hospitality | 2013 |
| Caroline Copp Ltd | Administrative & support | 2025 |
| Caroline Stearman Limited | Professional & scientific | 2014 |
| Carousel Properties Ltd | Construction | 2020 |
| Carre Ventures Limited | Professional & scientific | 2005 |
| Carrich House Guildford Limited | Other services | 1989 |
| Carrstone Renewables Ltd | Energy | 2025 |
| Carter Thomas Limited | Professional & scientific | 2013 |
| Carter Young Associates Limited | Professional & scientific | 2017 |
| Carthouse Construction Limited | Construction | 2018 |
| Carvanfreight Ltd | Transport & logistics | 2025 |
| Carys Media Ltd | Arts & recreation | 2025 |
| Carys Studio Limited | Arts & recreation | 2025 |
| Casa Reality Holdings Limited | Real estate | 2023 |
| Cascade Software Limited | Information & communication | 1990 |
| Castle Arch Advisory Ltd | Professional & scientific | 2018 |
| Castle Builders Ltd | Construction | 2010 |
| Castle Hairdressing Limited | Other services | 2005 |
| Castle Peak Ltd | Real estate | 2020 |
| Castlegate Lights Limited | Wholesale & retail | 2009 |
| Castlerock Group Ltd | Construction | 2021 |
| Castor Court Management Company Limited | Households | 2010 |
| Cat & Mouse Ventures Ltd | Professional & scientific | 2020 |
| Catalbas and Partners Ltd | Professional & scientific | 2021 |
| Catalyst Market Solutions Ltd | Professional & scientific | 2012 |
| Catchm Limited | Professional & scientific | 2020 |
| Cathayford Ltd | Wholesale & retail | 2024 |
| Cathedral Hill LLP | | 2009 |
| Catherine Whiting Art Ltd | Professional & scientific | 2024 |
| Catherine's Walk Limited | Households | 2015 |
| Catlin Young Commercial Limited | Real estate | 2014 |
| Cats-Cattery LLP | | 2024 |
| Cauvery Consulting Ltd | Information & communication | 2017 |
| Cavai UK Limited | Information & communication | 2019 |
| Cavalier Game Developments Ltd | Information & communication | 2022 |
| Cavalier Game Studios Ltd | Information & communication | 2012 |
| Cavallino Rampante Limited | Wholesale & retail | 2025 |
| Cavender Property Solutions Limited | Real estate | 2012 |
| Cavender Residential Sales (Guildford) Limited | Real estate | 2014 |
| Cavendish French Limited | Wholesale & retail | 1994 |
| Cavendish House (Residents) Management Limited | Households | 2003 |
| Cavendish Place (Guildford) Residents Association Limited | Households | 2002 |
| Cavey Laboratory Engineering Company Limited | Manufacturing | 2011 |
| Cbdshop.Today Ltd | Wholesale & retail | 2019 |
| Cbip Logistics (UK) Limited | Transport & logistics | 2024 |
| CBR Technologies Limited | Manufacturing | 2017 |
| Ccgh Limited | Administrative & support | 2010 |
| CDG Homes Limited | Real estate | 2019 |
| CDT 123 Limited | Financial services | 2015 |
| Cdwuk Ltd | Information & communication | 2022 |
| Cecan Ltd | Information & communication | 2018 |
| Cecey Treats Ltd | Hospitality | 2025 |
| Cedar River Homes Ltd | Construction | 2014 |
| Cedarlarch Limited | Construction | 1982 |
| Cedia Media Ltd | Information & communication | 2010 |
| Cellbxhealth Europe Limited | Professional & scientific | 2006 |
| Cellbxhealth PLC | Professional & scientific | 2003 |
| Cellcarta UK Limited | Financial services | 2019 |
| Celtic Luck Ltd | Information & communication | 2025 |
| Cemit Ltd | Transport & logistics | 2024 |
| Centline Ltd | Wholesale & retail | 2012 |
| Central Guildford Estates Management Ltd | Households | 2016 |
| Central Resources (UK) Limited | Professional & scientific | 2000 |
| Centre for Domestic Abuse and Violence Community Interest Company | Health & social care | 2018 |
| Centro Sourcing UK Ltd | Wholesale & retail | 2014 |
| Ceramic Design (Wholesale) Ltd | Wholesale & retail | 1992 |
| Ceramic Designs Limited | Real estate | 2020 |
| Ceramics Design Limited | Extraterritorial | 2010 |
| Cerdar Capital Limited | Real estate | 2026 |
| Cerise Publishing Ltd | Wholesale & retail | 2020 |
| Cerulean Winds (Ukcs) Limited | Energy | 2021 |
| Cerulean Winds Aspen Project Limited | Energy | 2023 |
| Cerulean Winds Beech Project Limited | Energy | 2023 |
| Cerulean Winds Cedar Project Limited | Energy | 2023 |
| Cerulean Winds Limited | Energy | 2020 |
| Cervus Plus Consulting LLP | | 2021 |
| Cervus Plus Ltd | Professional & scientific | 2024 |
| Cetus Maritime (UK) Limited | Transport & logistics | 2016 |
| CFB Consultancy Limited | Professional & scientific | 2026 |
| CFC Retinalyze UK Limited | Information & communication | 2022 |
| CFH Capital (UK) Limited | Financial services | 2021 |
| CFI Systems Limited | Construction | 2013 |
| Cfmc Solutions Limited | Construction | 2013 |
| CG Communications Limited | Professional & scientific | 2019 |
| CGS Medical Limited | Education | 2023 |
| CH Game Development UK Ltd | Information & communication | 2025 |
| Chaco Limited | Real estate | 2002 |
| Chaco TR Limited | Other services | 2025 |
| Chadsan Limited | Professional & scientific | 2015 |
| Chainbreaker the Film Limited | Information & communication | 2025 |
| Chalkdown Ltd | Wholesale & retail | 2020 |
| Challenging Expectations Limited | Information & communication | 2005 |
| Chamber Consulting Limited | Professional & scientific | 2019 |
| Chamber Hospitality Limited | Hospitality | 2023 |
| Chambers Advisory Ltd | Professional & scientific | 2025 |
| Chambers Waste Management Limited | Water & waste | 1975 |
| Chameleoni SMS Ltd | Information & communication | 2024 |