| Chrome 191 Consulting Ltd | Information & communication | 2023 |
| Chrome Project Solutions Ltd | Information & communication | 2011 |
| Chronos Supply Ltd | Wholesale & retail | 2025 |
| Chrysalis Properties Ltd | Real estate | 2013 |
| Chsmile Ltd | Health & social care | 2023 |
| Chuck 3D - Design Engineering Consultant Ltd | Construction | 2022 |
| Chunky Chips Soton Limited | Hospitality | 2023 |
| Church Hill Clinic Ltd | Health & social care | 2022 |
| Churchill Property Developments Limited | Real estate | 1999 |
| Churchills Family Funeral Directors Limited | Other services | 2011 |
| Churchleigh Limited | Real estate | 2001 |
| Chyborg Ltd | Professional & scientific | 2017 |
| Chyper Saar Ltd | Wholesale & retail | 2026 |
| Ciaran Hughes Visual Communication Limited | Administrative & support | 2014 |
| Cielo Parlour Limited | Hospitality | 2019 |
| Cinder Restaurants Ltd | Hospitality | 2020 |
| Cinder SJW Ltd | Hospitality | 2021 |
| Cinnamon Grand Venture Ltd | Real estate | 2021 |
| Cinnamon Ventures Ltd | Real estate | 2020 |
| Circle Creative Limited | Information & communication | 2003 |
| Circle Mills Ltd | Wholesale & retail | 2012 |
| Circular Facilities (London) Limited | Professional & scientific | 1961 |
| Circular Properties Limited | Professional & scientific | 2004 |
| Circus Maximus Ltd | Administrative & support | 2005 |
| Citadel Commercial Consulting Ltd | Information & communication | 2026 |
| Citicentre Limited | Administrative & support | 2018 |
| Citie Consulting Ltd | Information & communication | 2019 |
| Citiplants Limited | Wholesale & retail | 2022 |
| City and Western (London) Limited | Administrative & support | 2012 |
| City Chariots Ltd | Information & communication | 2026 |
| City Corporate Consulting Limited | Professional & scientific | 2003 |
| City of London Estates Limited | Real estate | 1968 |
| City of London Holdings & Investments Limited | Real estate | 1973 |
| City Scaffolding London Ltd | Construction | 2020 |
| Citycom Limited | Information & communication | 1994 |
| Civic Assist Holdings Ltd | Financial services | 2026 |
| Civic Assist Ltd | Information & communication | 2025 |
| Civilised Car Group Limited | Wholesale & retail | 2018 |
| CJ Commodities UK Limited | Wholesale & retail | 2014 |
| CJ Consultants (Essex) Limited | Professional & scientific | 2010 |
| CJR Estates Limited | Real estate | 2020 |
| Cjss Limited | Administrative & support | 2009 |
| CJW Accounting Ltd | Professional & scientific | 2016 |
| CK Kingdom Ltd | Real estate | 2026 |
| CKN Designs Limited | Administrative & support | 2011 |
| CKN Property Ventures LLP | | 2020 |
| Cladan Investments Ltd | Administrative & support | 1985 |
| Claddagh Developments Limited | Construction | 1996 |
| Claire Crowley Portable and Collectable Limited | Wholesale & retail | 2013 |
| Clairwood Limited | Administrative & support | 2013 |
| Clandestine Labs Limited | Information & communication | 2025 |
| Claregate (Little Heath) Management Company Limited | Households | 2010 |
| Claret Development Limited | Administrative & support | 2017 |
| Claridges Estates Limited | Real estate | 1991 |
| Claridges Finance Limited | Financial services | 2018 |
| Clarissa Farr Consulting Limited | Education | 2019 |
| Clarity Property Group Ltd | Extraterritorial | 2025 |
| Clarke Close Property Limited | Real estate | 2023 |
| Clarke Kent Consultancy UK Limited | Professional & scientific | 2019 |
| Clarmans Holdings Limited | Hospitality | 2001 |
| Clarus Vision Ltd | Health & social care | 2013 |
| Classic Car Wash Limited | Other services | 2017 |
| Classic Education Private Limited | Education | 2019 |
| Classic Glass Ltd | Construction | 2014 |
| Classic Property Investments Limited | Households | 1999 |
| Classic Vespa Club Ltd | Wholesale & retail | 2021 |
| Claybee Court (Palmerston Road) Property Management Company Limited | Households | 2017 |
| Clean Food Group Limited | Wholesale & retail | 2019 |
| CLEAN4GREEN Ltd | Water & waste | 2024 |
| Cleaner Direct Ltd | Administrative & support | 2008 |
| Cleaner Direct UK Ltd | Administrative & support | 2008 |
| Cleanse Force UK Limited | Administrative & support | 2017 |
| Clear Legacy Planning Ltd | Professional & scientific | 2026 |
| Clear Signal Creative Ltd | Information & communication | 2026 |
| Clearinsight Group Limited | Administrative & support | 2020 |
| Clearleaf Limited | Wholesale & retail | 2018 |
| Clearly Electrical Ltd | Construction | 2003 |
| Clearview Building Solutions CBS Limited | Construction | 2026 |
| Cleary and Hall Limited | Manufacturing | 2011 |
| Clec Homes Limited | Real estate | 2004 |
| Cleo M Ltd | Construction | 2008 |
| Cleo M Properties Ltd | Real estate | 2021 |
| Cleveland 9 Estates Limited | Administrative & support | 2020 |
| Clever Clogs Limited | Other services | 1993 |
| Click 4 Credit Management Ltd | Administrative & support | 2016 |
| Click Return Limited | Information & communication | 2012 |
| Click-Right Limited | Information & communication | 2007 |
| Cliftonshire Limited | Arts & recreation | 1983 |
| Clik Productions Ltd | Information & communication | 2019 |
| Clinical Hub Ltd | Health & social care | 2024 |
| Clive Lodge Management Limited | Households | 1972 |
| Clms (UK) Limited | Information & communication | 1998 |
| Clobber of London Ltd | Wholesale & retail | 2025 |
| Cloisters (Crouchfields) Management Co. Limited(The) | Households | 1985 |
| Cloud Concierge Services Ltd | Administrative & support | 2025 |
| Cloud Customs Solutions Ltd | Transport & logistics | 2023 |
| Cloud Mantra Limited | Information & communication | 2011 |
| Clouds Above Business Travel Limited | Administrative & support | 2013 |
| Clovullin Associates Limited | Administrative & support | 2017 |
| CLS Decorating Ltd | Construction | 2025 |