| Clearwater A&D Limited | Professional & scientific | 2009 |
| Cleestone Limited | Construction | 2021 |
| Clent Properties Limited | Construction | 2023 |
| Clentech Consulting Limited | Professional & scientific | 2017 |
| Clever Clogs IP Ltd | Administrative & support | 2016 |
| Clickchart Limited | Professional & scientific | 2002 |
| Clifford Estates Ltd | Real estate | 2021 |
| Climate Solutions (Droitwich) Ltd | Construction | 2015 |
| Climb Commerce Ltd | Information & communication | 2016 |
| Cloud Cortex Communications Ltd | Information & communication | 2022 |
| Cloud Cortex Group Ltd | Information & communication | 2022 |
| Cloud Cortex Ltd | Information & communication | 2016 |
| Cloud-Works Solutions Limited | Administrative & support | 2010 |
| Cloudshade Limited | Construction | 2016 |
| Club 11 London Ltd | Administrative & support | 2016 |
| Clueless? App Ltd | Information & communication | 2024 |
| CMH Roofing Specialists Ltd | Construction | 2024 |
| Cmpl Limited | Professional & scientific | 2011 |
| CMT Advantage Limited | Administrative & support | 2016 |
| CNC Parts and Services Limited | Manufacturing | 2025 |
| CND Cars Ltd | Wholesale & retail | 2024 |
| Co LAB H.E.A.L.T.H 510 Ltd | Education | 2020 |
| Coalesce Entertainment Group Limited | Arts & recreation | 2023 |
| Cocktail HQ Ltd | Real estate | 2022 |
| Codefast Systems Limited | Information & communication | 2007 |
| Coffee Masters UK Limited | Wholesale & retail | 2014 |
| Cognati Group Limited | Financial services | 2024 |
| Collaborative Business Solutions (U.K.) Limited | Financial services | 2019 |
| Collective Twenty 5 Limited | Professional & scientific | 2025 |
| Collobyincas Limited | Health & social care | 2020 |
| Comedy Bandits Ltd | Arts & recreation | 2025 |
| Comenco Group Limited | Professional & scientific | 1997 |
| Compac Sorting Equipment UK Limited | Administrative & support | 2015 |
| Complaintassist.Co.Uk Limited | Information & communication | 2012 |
| Complete Electrical Services(Gb) Limited | Construction | 2022 |
| Complex Metal Services Limited | Wholesale & retail | 2020 |
| Comprehensive Oncology Limited | Health & social care | 2014 |
| Compton Residential Development Limited | Administrative & support | 2018 |
| Comtherm Limited | Manufacturing | 1989 |
| Concordia HR Ltd | Administrative & support | 2023 |
| Confi-Kids Limited | Health & social care | 2018 |
| Conformite Ltd | Professional & scientific | 2021 |
| Connaught Financial Services Limited | Administrative & support | 2017 |
| Connectalk Limited | Other services | 2017 |
| Connoisseurs Fine Foods Ltd. | Hospitality | 2003 |
| Connolly Heart Ltd | Health & social care | 2018 |
| Consafe Global Consulting Limited | Professional & scientific | 2026 |
| Consciously Blooming Business Ltd | Professional & scientific | 2024 |
| Consolidated Rentals Limited | Extraterritorial | 2015 |
| Construction Apps Limited | Information & communication | 2020 |
| Constructs Building Limited | Construction | 2024 |
| Constructs Group Limited | Financial services | 2024 |
| Container Components Europe Limited | Manufacturing | 1994 |
| Contemporary Driveways Ltd | Construction | 2025 |
| Contextual Consulting Ltd | Health & social care | 2016 |
| Contract Commercial Management Limited | Construction | 2008 |
| Contract Packers Limited | Agriculture & fishing | 2003 |
| Convenient Home and Garden Limited | Wholesale & retail | 2022 |
| Conveyor Projects Ltd | Professional & scientific | 2014 |
| Cooks Development Limited | Real estate | 2021 |
| Cool Forage Ltd | Agriculture & fishing | 2019 |
| Coole Projects Limited | Financial services | 2023 |
| Copcut Golf Centre Limited | Arts & recreation | 2005 |
| Copperfield House Management Limited | Households | 1992 |
| Corbett Consultants Limited | Information & communication | 2023 |
| Corbett Finance Limited | Administrative & support | 2020 |
| Corbett Orthopaedics Ltd | Health & social care | 2026 |
| Corbital Ltd | Administrative & support | 2017 |
| Core Financial Efficiencies Limited | Administrative & support | 2020 |
| Core Pro Audio Ltd | Wholesale & retail | 2019 |
| Core Pro Studio Limited | Other services | 2025 |
| Cornet Switching Systems Limited | Information & communication | 1997 |
| Correa Property Limited | Real estate | 2016 |
| Corse QA Ltd | Professional & scientific | 2015 |
| Coseley (Freeholders) Management Company Limited | Households | 2000 |
| Cosgrove Developments Ltd | Construction | 2014 |
| Cosgrove Restoration Ltd | Real estate | 2020 |
| Cosmetic Surgery Partnership Limited | Health & social care | 2005 |
| Cosmic Code Gaming Ltd | Financial services | 2024 |
| Costello's Holdings Ltd | Financial services | 2026 |
| Cotswold Civil Engineering Ltd | Construction | 2020 |
| Cotswold Spine Ltd | Health & social care | 2025 |
| Cotswold Urology Ltd | Health & social care | 2017 |
| Cottonmello Ltd | Administrative & support | 2020 |
| Country Girl Management Company Limited | Households | 2016 |
| Countryside Ventures Limited | Households | 2026 |
| County Cladding Systems Limited | Construction | 2005 |
| County Contract Flooring Services Limited | Construction | 2026 |
| County to County Professional Limited | Construction | 2008 |
| Court Farm Estates Limited | Hospitality | 2022 |
| Cove Tanning Studio Limited | Other services | 2025 |
| Coventry and Warwickshire Integrated Primary Care Ltd | Health & social care | 2020 |
| COW on the Ice Productions Ltd | Arts & recreation | 2023 |
| COX 2K Property Management Ltd | Real estate | 2016 |
| CPS Performance Cars Ltd | Wholesale & retail | 2019 |
| Crab Leisure Limited | Hospitality | 2017 |
| Crafted Music Publishing Limited | Information & communication | 2011 |
| Craftibeer Limited | Wholesale & retail | 2016 |
| Crazyfuncastles.Com Limited | Administrative & support | 2015 |
| CRB Consultancy Ltd | Administrative & support | 2016 |