| CJR Coaching Consultancy Ltd | Other services | 2024 |
| CJS International Ltd | Transport & logistics | 2016 |
| CJS Pets 2 U C.I.C. | Arts & recreation | 2023 |
| CK 2026 Ltd | Hospitality | 2026 |
| CK Accounting Services Ltd | Professional & scientific | 2024 |
| CK Automotive Services Ltd | Wholesale & retail | 2022 |
| CK Derby Limited | Hospitality | 2025 |
| CKL Center Ltd | Wholesale & retail | 2017 |
| CL Social Limited | Professional & scientific | 2025 |
| Claims Management Association Limited | Other services | 2024 |
| Clair DE Lune Management Limited | Households | 2021 |
| Clair Jackson Limited | Other services | 2005 |
| Claire Chaplin Limited | Other services | 2002 |
| Claire's Hair Limited | Other services | 2023 |
| Clairville Grange Management Company Limited | Households | 2015 |
| Clancy Construction & Civil Engineering Limited | Construction | 2019 |
| Clann Property Developments Limited | Construction | 2025 |
| Clann Property Limited | Construction | 2025 |
| Clare Baggaley Limited | Other services | 2011 |
| Clare Eames Limited | Professional & scientific | 2011 |
| Clare Holland Interior Creations Ltd | Professional & scientific | 2012 |
| Clare Knights Limited | Financial services | 2021 |
| Claredan Estates Ltd | Real estate | 2015 |
| Claremont Sofa Designs Limited | Manufacturing | 2014 |
| Clarence Property Investments Limited | Real estate | 2016 |
| Claret (Eco) Ltd | Agriculture & fishing | 2021 |
| Claridge Fine Art Ltd | Professional & scientific | 2015 |
| Clarina Retail Limited | Wholesale & retail | 2019 |
| Clarion Creations Ltd | Information & communication | 2017 |
| Clarissa Stefania Limited | Other services | 2015 |
| Claritas Financial Planning Ltd | Financial services | 2022 |
| Clarity Diabetes Limited | Health & social care | 2024 |
| Clarity Over Clout Ltd | Financial services | 2026 |
| Clark CX Ltd | Information & communication | 2012 |
| Clark Keys Limited | Real estate | 2019 |
| Clark's Cycle Systems Limited | Manufacturing | 2004 |
| Clark's Group Limited | Other services | 2018 |
| Clarke Engineering Services Derby Ltd | Construction | 2013 |
| Clarke Tinkler LLP | | 2016 |
| Clarke Warren Ltd | Information & communication | 2025 |
| Clarke's Plumbing & Heating Ltd | Construction | 2018 |
| Clarks Group Holdings Limited | Financial services | 2024 |
| Clarky Consulting Limited | Manufacturing | 2022 |
| Claror Consulting Limited | Professional & scientific | 2024 |
| Clarus Developments Limited | Construction | 2021 |
| Clarus Living (Midlands) Limited | Construction | 2021 |
| Class 1 Entertainments Limited | Arts & recreation | 2002 |
| Class ACT Hair Limited | Other services | 2018 |
| Classic CUT Derby Ltd | Other services | 2025 |
| Classic Inside OUT Limited | Construction | 2023 |
| Classic KIT Corner Ltd | Wholesale & retail | 2025 |
| Claudio Obras Limited | Construction | 2023 |
| Claudio's Construction and Building Ltd | Construction | 2025 |
| Clay Cross Estate Management Company Limited | Households | 2018 |
| Clay Target Events Ltd | Education | 2016 |
| Claymore Marine Ltd | Manufacturing | 2014 |
| Claytan Ceramics International Limited | Wholesale & retail | 2003 |
| Clayton & Co Lettings Limited | Real estate | 2023 |
| Clayton Engineering (UK) Limited | Manufacturing | 2011 |
| Clayton Lenagh Brickwork Limited | Construction | 2001 |
| CLD Investments Ltd | Real estate | 2023 |
| Clean 2 U Limited | Administrative & support | 2022 |
| Clean Living International Limited | Wholesale & retail | 2018 |
| Clean Slate (UK) Ltd | Administrative & support | 1994 |
| Clean Slate (Windows) Limited | Administrative & support | 2022 |
| CLEAN360 Ltd | Administrative & support | 2015 |
| CLEAN360 U.K Ltd | Administrative & support | 2022 |
| Cleanabuild Limited | Administrative & support | 2019 |
| Cleanflip Ltd | Administrative & support | 2025 |
| Cleanhills Limited | Households | 2024 |
| Cleanride Ltd | Administrative & support | 2025 |
| Clear Choice Windows Doors and Conservatories Ltd | Construction | 2024 |
| Clear Online Ltd | Wholesale & retail | 2008 |
| Clear Open Consultancy Limited | Information & communication | 2015 |
| Clear Path Construction Ltd | Construction | 2025 |
| Clear Sky Performance Ltd | Other services | 2017 |
| Clear Vision Properties Limited | Real estate | 2003 |
| Clear Wave Ultrasonics Ltd | Manufacturing | 2025 |
| Clearance Clarence Limited | Water & waste | 2020 |
| Clearbond Law Limited | Professional & scientific | 2019 |
| Cleardeskpro CIC | Information & communication | 2025 |
| Cleardeskpro Software Ltd | Information & communication | 2026 |
| Clearing Business Payments Ltd | Extraterritorial | 2024 |
| Clearpath (U.K.) Limited | Information & communication | 2024 |
| Clearshield Windows Ltd | Construction | 2007 |
| Clearstone Ltd | Wholesale & retail | 2026 |
| Clearwell Quarries Limited | Extraterritorial | 1959 |
| Cleaver Meats Limited | Wholesale & retail | 1981 |
| Clements Limited | Manufacturing | 1993 |
| Clerman Recruitment Limited | Professional & scientific | 1992 |
| Cleve Wood Residents Management Company Limited | Households | 2022 |
| Clever Computer Solutions Limited | Information & communication | 2006 |
| Clever Design Solutions Limited | Information & communication | 2015 |
| Cleverclogs (Longwater) Limited | Education | 2011 |
| Cleverclogs (Norwich) Limited | Education | 2011 |
| Cliaison Ltd | Wholesale & retail | 2024 |
| Clic Properties Ltd | Real estate | 2024 |
| Click Hub Limited | Wholesale & retail | 2024 |
| Click N Kart Ltd | Wholesale & retail | 2025 |
| Click&Save Ltd | Wholesale & retail | 2024 |