| Chilly Charcoal Chicken Company Limited | Manufacturing | 2016 |
| Chimaira Investment Ltd | Real estate | 2019 |
| China Arts Limited | Arts & recreation | 2005 |
| China-Britain Business Fusion Ltd | Professional & scientific | 2011 |
| Chloessa Limited | Administrative & support | 2010 |
| Choptech Limited | Financial services | 2025 |
| Choudhary Developments 1 Limited | Real estate | 2021 |
| Chowtime Ltd | Real estate | 2010 |
| Chris Rogers Limited | Construction | 2008 |
| Christchurch Kindergarten Childrens Nursery Limited | Health & social care | 2009 |
| Christian Lawrence Limited | Manufacturing | 2025 |
| Christopher Edwards Limited | Real estate | 2012 |
| Chromosome Ltd | Hospitality | 2019 |
| Churchill Court (Nugents Park) Management Company Limited | Real estate | 1994 |
| Cioraru Limited | Transport & logistics | 2016 |
| CIP Electrical Ltd | Construction | 2021 |
| Ciprio Consulting Limited | Information & communication | 2020 |
| Circle K Investments Limited | Construction | 2017 |
| Citrine Lettings Ltd | Real estate | 2023 |
| Citrine Services Ltd | Information & communication | 2015 |
| City Avenue Holdings Limited | Financial services | 2018 |
| City Avenue Limited | Administrative & support | 2018 |
| City Brunch Catering Ltd | Hospitality | 2019 |
| City Brunch Ltd | Hospitality | 2018 |
| City Consultants RDC Limited | Information & communication | 2015 |
| City Escapes Homes Limited | Real estate | 2020 |
| City Financial Mortgages Ltd | Financial services | 2013 |
| City-Concierge Limited | Other services | 2002 |
| Citybution Ltd | Administrative & support | 2021 |
| Citywest Investments UK Limited | Real estate | 2003 |
| Cjjp Holdings Limited | Financial services | 2024 |
| Ckdk Holdings Ltd | Financial services | 2025 |
| Ckfx Trading Limited | Financial services | 2025 |
| Claims Advice Bureau (PPI) Limited | Professional & scientific | 2011 |
| Clanvision Ltd | Health & social care | 2014 |
| Claris Investments Limited | Real estate | 2017 |
| Clarity Cleaning Services Ltd | Other services | 2007 |
| Clarity Gift Card Consulting Limited | Professional & scientific | 2016 |
| Clarksport Limited | Administrative & support | 1999 |
| Classic Legends Ltd | Wholesale & retail | 2024 |
| Claystone Ltd | Professional & scientific | 2011 |
| CLD Building Solutions Limited | Construction | 2022 |
| Clean Beale Services Ltd | Administrative & support | 2015 |
| Cleanny Property Services Ltd | Administrative & support | 2023 |
| Clear & Obvious Limited | Administrative & support | 2019 |
| CLEAR21 UK Limited | Information & communication | 2024 |
| Clearly Loans Limited | Financial services | 2012 |
| Clentran Limited | Professional & scientific | 2021 |
| Clever Monkey Solutions Ltd | Professional & scientific | 2014 |
| Clever Trevor Limited | Information & communication | 2018 |
| Cleverly Advisory Services Ltd | Financial services | 2011 |
| Clewbox Limited | Real estate | 2023 |
| Click Ventures Limited | Wholesale & retail | 2005 |
| Clickfair Ltd | Wholesale & retail | 2024 |
| Clifford & Co Europe Limited | Professional & scientific | 2000 |
| Clifford & Co Secretaries Limited | Professional & scientific | 2008 |
| Clifford & Co UK Administration Limited | Professional & scientific | 2008 |
| Clifford Nominees Limited | Professional & scientific | 2008 |
| Clifton & Wellington Capital Ltd | Financial services | 2026 |
| Cliniclogos.Ai CIC | Manufacturing | 2024 |
| Clinicplasticsurgery Ltd | Health & social care | 2022 |
| Clonard Consulting Ltd | Professional & scientific | 2021 |
| Cloud Accounting Partners Ltd | Administrative & support | 2017 |
| Cloud Ahead Limited | Information & communication | 2017 |
| Cloud Count Solutions Ltd | Professional & scientific | 2025 |
| Cloud Infrastructure Services Limited | Information & communication | 2014 |
| Cloud-Mass Limited | Information & communication | 2016 |
| Cloudethos Ltd | Professional & scientific | 2025 |
| Cloudnacre Limited | Administrative & support | 2023 |
| Cloudsourcing Ltd | Professional & scientific | 2020 |
| Cloudzon UK Limited | Administrative & support | 2014 |
| Clubok Ltd | Education | 2015 |
| CM Group Surbiton Limited | Hospitality | 2018 |
| CMC Hospitality Software Ltd | Information & communication | 2022 |
| Coach Continuum Ltd | Professional & scientific | 2024 |
| Coaching on Purpose Ltd | Professional & scientific | 2020 |
| Coastal Crest Estates Ltd | Real estate | 2023 |
| Cobrest Limited | Wholesale & retail | 1977 |
| Coco Edgware Ltd | Hospitality | 2024 |
| Coco Interior Design Limited | Construction | 2005 |
| Coda Filmworks Limited | Information & communication | 2023 |
| Cogent Logistics Ltd | Transport & logistics | 2019 |
| Cognati Ltd | Wholesale & retail | 2020 |
| Cole's Kitchen London Limited | Hospitality | 2024 |
| Colesce Ltd | Information & communication | 2022 |
| Colhay's Limited | Wholesale & retail | 2018 |
| Colin Cracknell & Associates Limited | Professional & scientific | 2011 |
| Collected Objects Ltd | Information & communication | 2020 |
| College of Accountancy (UK) Ltd | Education | 2008 |
| Collins Motors Ltd | Extraterritorial | 2003 |
| Colourcar Ltd | Information & communication | 2016 |
| Colourful Canvas Ltd | Professional & scientific | 2022 |
| Colourful Smudges Ltd | Professional & scientific | 2019 |
| Colourgem Designs Ltd. | Financial services | 2009 |
| Colquhoun & Colquhoun Limited | Administrative & support | 2009 |
| Colwyn Bay Old Convent Nursing Home Limited | Health & social care | 2016 |
| Comal 11 Limited | Construction | 2016 |
| Combat Recruitment Ltd | Administrative & support | 2020 |
| Combination Property Ltd | Real estate | 2023 |
| Combustion Interactive Communications Limited | Real estate | 2009 |