| Commercial Domestic Property Management Ltd | Extraterritorial | 2021 |
| Commercial GAS Systems Ltd | Construction | 2012 |
| Commercial Liberty Ltd | Information & communication | 2020 |
| Commercial Plant Services Ltd | Administrative & support | 2007 |
| Commercial Street Limited | Wholesale & retail | 2013 |
| Commercial Tree Surgery & Site Clearance Ltd | Other services | 2026 |
| Commodo Investments Limited | Real estate | 2023 |
| Common Ground Ventures CIC | Professional & scientific | 2026 |
| Commons College Ltd | Education | 2015 |
| Comms Trade Limited | Wholesale & retail | 2020 |
| Commscraft Limited | Information & communication | 2019 |
| Commsupport Networks Limited | Information & communication | 2007 |
| Communication Means Limited | Professional & scientific | 2013 |
| Communicator Consulting Limited | Professional & scientific | 2012 |
| Communicator Limited | Information & communication | 1987 |
| Community Advancement Fund C.I.C. | Financial services | 2013 |
| Community Connex Ltd. | Health & social care | 1986 |
| Community Imaging Services Limited | Health & social care | 2018 |
| Community Tech Solutions Ltd | Information & communication | 2024 |
| Commute Technologies Limited | Information & communication | 2019 |
| Compani Limited | Information & communication | 2025 |
| Comparethecoffin.Com Limited | Other services | 2011 |
| Compass Shield Advisors Ltd | Administrative & support | 2025 |
| Compconsult Limited | Extraterritorial | 2020 |
| Competitive Options Limited | Other services | 2003 |
| Complete Mortgage Advice Centre Limited | Financial services | 2004 |
| Complete Serv UK Ltd | Manufacturing | 2025 |
| Completehome Projects Ltd | Construction | 2022 |
| Compliance Associates Ltd | Professional & scientific | 2009 |
| Compliance Direct Ltd | Professional & scientific | 2014 |
| Compliance Pharmahub Ltd | Manufacturing | 2025 |
| Compliance Solutions Holdings Limited | Financial services | 2022 |
| Complydent Consultancy & Management Ltd | Administrative & support | 2018 |
| Composite Panels & Cladding Installation Ltd | Construction | 2025 |
| Compounder Mechanics Limited | Professional & scientific | 2026 |
| Compton Estate Management Company Limited | Households | 2004 |
| Compton London Ltd | Construction | 2017 |
| Compubits Support Limited | Information & communication | 2002 |
| Compusoft-Uk Limited | Information & communication | 1996 |
| Computer (U K) Limited | Information & communication | 1987 |
| Computers ETC Limited | Wholesale & retail | 2010 |
| Comseal Limited | Other services | 2016 |
| Comtrade (UK) Limited | Professional & scientific | 1996 |
| Conamara Construction Ltd | Construction | 2020 |
| Conard Property Holdings Ltd | Real estate | 2023 |
| Concept Cuisine Enterprises Limited | Hospitality | 2019 |
| Concept Marketing (UK) Limited | Wholesale & retail | 2013 |
| Conch 22 Limited | Wholesale & retail | 2025 |
| Concilium Group Limited | Financial services | 2015 |
| Concord Construction Ltd. | Construction | 2017 |
| Concord Homes Ltd | Construction | 2017 |
| Concord Properties Limited | Real estate | 2017 |
| Concord Road Ltd | Real estate | 2026 |
| Concordia Advisory Ltd | Professional & scientific | 2023 |
| Concrete Clarity Ltd | Construction | 2025 |
| Concrete Restorations Limited | Construction | 1992 |
| Concrete Stairs Limited | Construction | 2012 |
| Condor Associates Limited | Professional & scientific | 2004 |
| Condor Network Services Limited | Information & communication | 2010 |
| Conect Telecom Ltd | Construction | 2024 |
| Conexstra Technologies Limited | Information & communication | 2009 |
| Confederation Studio Ltd | Professional & scientific | 2013 |
| Conferro Auctions Limited | Wholesale & retail | 2013 |
| Confinement Movie Limited | Information & communication | 2025 |
| Congar Housing Limited | Administrative & support | 2014 |
| Congress House Nominees Limited | Professional & scientific | 2025 |
| Connect Languages Ltd | Professional & scientific | 1990 |
| Connect PAT Testing Limited | Professional & scientific | 2008 |
| Connect Waze Private Limited | Wholesale & retail | 2017 |
| Connectcomp Ltd | Information & communication | 2014 |
| Connected Ideas Limited | Information & communication | 2011 |
| Connection Holdings Limited | Real estate | 2023 |
| Connectivity IT Solutions Ltd | Information & communication | 2021 |
| Conner Building Services Ltd | Manufacturing | 2024 |
| Connexion Electrical Holdings Limited | Professional & scientific | 2010 |
| Connuct Limited | Information & communication | 2017 |
| Conova Construction Ltd | Construction | 2022 |
| Conquest Configurations Limited | Wholesale & retail | 2009 |
| Conscious Work Company Ltd | Administrative & support | 2025 |
| Conseil International Limited | Professional & scientific | 2004 |
| Consentius Limited | Education | 2025 |
| Consequent AI Ltd | Professional & scientific | 2024 |
| Consiglieri Limited | Extraterritorial | 2024 |
| Consiliam Consulting Limited | Wholesale & retail | 2011 |
| Consiliam Holdings Limited | Financial services | 2011 |
| Consiliam Limited | Professional & scientific | 2009 |
| Consortial Holdings UK Ltd | Financial services | 2026 |
| Constance Securities Limited | Administrative & support | 2006 |
| Constant Carpet Care Ltd | Construction | 2025 |
| Constant Elevation Ltd | Real estate | 2015 |
| Constantin Tambac Ltd | Construction | 2025 |
| Constantine Consulting Ltd | Construction | 2014 |
| Constantinople Spice Consortium Limited | Wholesale & retail | 2020 |
| Constellation Digital Limited | Information & communication | 2014 |
| Constellation Partners Limited | Professional & scientific | 2006 |
| Construct 360 Ltd | Professional & scientific | 2005 |
| Construct Xpert Gulf Limited | Construction | 2023 |
| Constructco Limited | Construction | 2008 |
| Constructhub Limited | Construction | 2023 |
| Construction DM Ltd | Construction | 2024 |