| CLW Sales Ltd | Wholesale & retail | 2023 |
| CMS Associates LLP | | 2013 |
| CMS Corporate Mailing Solutions Trustee Limited | Financial services | 2024 |
| CMS Property Maintenance Ltd | Construction | 2016 |
| CNC Techniques Limited | Manufacturing | 2014 |
| Coached Global Ltd | Education | 2024 |
| Code Tantra Limited | Information & communication | 2019 |
| Cognitive Construction Limited | Construction | 2017 |
| Cognitive Developments Ltd. | Real estate | 2019 |
| Coldside Engineering Ltd | Manufacturing | 2022 |
| Colin a Rose Consulting Ltd. | Information & communication | 2013 |
| Colt (Design and Build) Limited | Construction | 2024 |
| Comedge Partners Limited | Professional & scientific | 2025 |
| Comfort Hampers Ltd | Other services | 2015 |
| Community Contact Limited | Professional & scientific | 2014 |
| Compass New Media Limited | Information & communication | 2006 |
| Complete Cleaning Services (London) Limited | Administrative & support | 2007 |
| Complete Compliance Hub Ltd | Public administration | 2024 |
| Complete Eyecare Limited | Wholesale & retail | 2011 |
| Complete Shine Solutions Ltd | Administrative & support | 2026 |
| Compliance Angels Ltd | Professional & scientific | 2014 |
| Conexpak Limited | Wholesale & retail | 1986 |
| Configurator Limited | Information & communication | 2019 |
| Connectedpensions Limited | Professional & scientific | 2024 |
| Conquered IT LLP | | 2021 |
| Conquest Select Cars Limited | Wholesale & retail | 2018 |
| Constant Precision Ltd | Manufacturing | 2013 |
| Consult MJ Ltd | Information & communication | 2025 |
| Consultancy Exchange Limited | Professional & scientific | 2009 |
| Contact Plant Limited | Extraterritorial | 2018 |
| Context in Development Ltd | Professional & scientific | 2018 |
| CONVERT2GROW Limited | Professional & scientific | 2025 |
| Convertspv Limited | Professional & scientific | 2023 |
| Cool Vibs PVT Ltd | Hospitality | 2021 |
| Cooley & SON Construction Limited | Construction | 2022 |
| Coombes Local GIN Limited | Wholesale & retail | 2020 |
| Coombstock Ltd | Wholesale & retail | 2024 |
| Copper Thief Distilling Co Ltd | Manufacturing | 2017 |
| Corby Painting and Decorating Ltd | Construction | 2018 |
| Cordata Holdings Limited | Real estate | 2023 |
| Core Beverage Equipment Ltd | Wholesale & retail | 2010 |
| Corlexa Contracts Ltd | Professional & scientific | 2025 |
| Cotswold Landrover Limited | Wholesale & retail | 2023 |
| Cotswold New Homes Limited | Construction | 2015 |
| Coughlan Commercial Brokers Limited | Financial services | 2012 |
| Country Wood Floors Ltd | Construction | 2018 |
| Courts Accountancy Services Limited | Professional & scientific | 1996 |
| Courts Accountants Ltd | Extraterritorial | 2015 |
| COW Parsley Productions Limited | Arts & recreation | 2011 |
| COX & Company Logistics Consulting Limited | Administrative & support | 2011 |
| COX & Roberts (Master Thatchers) South Ltd | Construction | 2018 |
| Coyote Moon Ltd | Other services | 2012 |
| Cozy COW UK Limited | Agriculture & fishing | 2016 |
| CQS Property Developments Limited | Financial services | 2024 |
| Crawford and Co. Creative Ltd | Professional & scientific | 2025 |
| Crawford Countryside Services Ltd | Construction | 2024 |
| Cream and Spoon Ltd | Manufacturing | 2017 |
| Creative JAM Ltd | Information & communication | 2015 |
| Cross Support Services Ltd | Professional & scientific | 2010 |
| Crown & Country Travel Ltd | Administrative & support | 2024 |
| Crumbs Catering Limited | Hospitality | 2020 |
| CS Contract Services Ltd | Construction | 2013 |
| CTM Solutions Ltd | Professional & scientific | 2021 |
| CTO Consulting Limited | Professional & scientific | 2015 |
| CTR Smart Repair Ltd | Wholesale & retail | 2021 |
| Cultural Zest Services Ltd | Professional & scientific | 2026 |
| Cuong Trang Ltd | Other services | 2023 |
| CUP & Cork Ltd | Hospitality | 2026 |
| Cutting Edge Construction Limited | Construction | 2012 |
| Cyber 1 Armor Limited | Information & communication | 2024 |
| Cyber Threat Consulting Limited | Professional & scientific | 2014 |
| Cyberlink Technology Limited | Information & communication | 2025 |
| Cybernexus Labs Limited | Information & communication | 2025 |
| Cybersecurity Wisdom Ltd | Information & communication | 2025 |
| Cycle Car Restoration Limited | Arts & recreation | 2012 |
| CYCLE4GOOD Ltd | Arts & recreation | 2016 |
| Cygnet Interiors Limited | Professional & scientific | 2005 |
| Cytomark Limited | Manufacturing | 2019 |
| D & a Agricultural Engineers Ltd | Professional & scientific | 2012 |
| D & D Quality Property Limited | Real estate | 2023 |
| D & I Imaging Ltd | Health & social care | 2018 |
| D Gibbins Limited | Hospitality | 2017 |
| D J Macarthur Engineering Limited | Professional & scientific | 2016 |
| D P Electrical Limited | Construction | 2006 |
| D Z Sports Limited | Arts & recreation | 2000 |
| D'Espaigne Consulting Limited | Health & social care | 2014 |
| D.J. Ridley Carpentry & Joinery Limited | Construction | 2002 |
| D.P. Wilkins Limited | Health & social care | 2004 |
| D.P.S Electrical MK Ltd | Construction | 2014 |
| D2H Advanced Technologies Ltd | Professional & scientific | 2020 |
| D2H Engineering Services Ltd | Professional & scientific | 2015 |
| D3 Racing Solutions Ltd | Arts & recreation | 2014 |
| Dadford Road Campsite & Parking Ltd | Hospitality | 2013 |
| Damax Limited | Other services | 1990 |
| DAN Clancy Ltd | Construction | 2025 |
| Dancing Squirrel Limited | Administrative & support | 2004 |
| Dandy Lions Child Boutique Limited | Wholesale & retail | 2011 |
| Daniel Calam Productions Ltd | Manufacturing | 2022 |
| Daniel Foote Limited | Transport & logistics | 2016 |
| Danquah Life Sciences Ltd | Professional & scientific | 2026 |