| Constructionology Ltd | Construction | 2019 |
| Constructions N&C Ltd | Construction | 2020 |
| Constructionsplus Limited | Construction | 2024 |
| Constructive Capital Group Ltd | Construction | 2023 |
| Constructive Co London Ltd | Construction | 2023 |
| Consulting GI Ltd | Administrative & support | 2019 |
| Consulting Paper Ltd | Education | 2022 |
| Consultsit Limited | Information & communication | 2025 |
| Consulvatic Limited | Professional & scientific | 2018 |
| Contact EYE Ltd | Wholesale & retail | 2023 |
| Contact Roller Shutters Limited | Manufacturing | 1999 |
| Contactless Car Rentals Ltd | Administrative & support | 2024 |
| Container Kitchens Ltd | Hospitality | 2023 |
| Contemporary Assist Limited | Professional & scientific | 2010 |
| Content Consultancy Solutions Limited | Other services | 2017 |
| Conti Carwil Ltd | Transport & logistics | 2017 |
| Conti London Limited | Transport & logistics | 2016 |
| Continental Business Service Limited | Administrative & support | 2020 |
| Continental Crunch Ltd | Wholesale & retail | 2026 |
| Continental Investment Holdings Ltd | Financial services | 2022 |
| Continental Smart Solutions Limited | Professional & scientific | 2012 |
| Contour Build Limited | Construction | 2012 |
| Contractors Security Ltd | Administrative & support | 2015 |
| Contraption Media Limited | Information & communication | 2011 |
| Convenant Limited | Other services | 2019 |
| Convenience Films Ltd | Information & communication | 2012 |
| Convenince Food & Wine Limited | Professional & scientific | 2017 |
| Converse IT Consultancy Ltd | Information & communication | 2012 |
| Converta Ltd | Financial services | 2016 |
| Convivium Food Limited | Hospitality | 2026 |
| Convo PEZ Ltd | Construction | 2024 |
| Conway Healthcare Limited | Wholesale & retail | 2006 |
| COOK4ALL Ltd | Hospitality | 2025 |
| Cookiepets Ltd | Wholesale & retail | 2025 |
| Cool Cargo Logistics Ltd | Transport & logistics | 2016 |
| Cool Tech Masterz Ltd | Manufacturing | 2026 |
| Coolcarla Limited | Construction | 2014 |
| Cooper & Young Ltd | Professional & scientific | 2018 |
| Cooper ARM Services Limited | Construction | 2024 |
| Cooper Leisuretime Limited | Administrative & support | 2004 |
| Cooperman & Goldberg Ltd | Construction | 2021 |
| Coopers Consultants Ltd | Professional & scientific | 2022 |
| Coorie Living Limited | Wholesale & retail | 2024 |
| Copconstruct Ltd | Manufacturing | 2022 |
| Copecrown Ltd | Wholesale & retail | 2020 |
| Coplica Records Ltd. | Information & communication | 2015 |
| Copperstone Estates Ltd | Real estate | 2014 |
| Coppia Limited | Administrative & support | 2012 |
| COR Meum Ltd | Information & communication | 2025 |
| Coral Perfumes UK Ltd | Wholesale & retail | 2023 |
| Coral Services Ltd | Construction | 2018 |
| Core Achievers Ltd | Education | 2024 |
| Core Comfort Essentials Ltd | Wholesale & retail | 2025 |
| Core Fintech Limited | Wholesale & retail | 2024 |
| Core Freight Ltd | Transport & logistics | 2025 |
| Core GAS Solutions Ltd | Construction | 2026 |
| Core Management Solutions Ltd | Administrative & support | 2021 |
| Core Point Management Ltd | Professional & scientific | 2026 |
| Core Studios Group Limited | Wholesale & retail | 2026 |
| Core Tech Enterprise Limited | Information & communication | 2025 |
| Core Unity Investment Ltd | Real estate | 2021 |
| Corebridge Limited | Wholesale & retail | 2025 |
| Coredo Ltd | Financial services | 2026 |
| Coreflame Heating Limited | Construction | 2025 |
| COREI8 Limited | Construction | 2026 |
| Corepath LAB Diagnostics Ltd | Professional & scientific | 2025 |
| Corevision Energy Company Ltd | Other services | 2018 |
| Corewebhoster Ltd | Information & communication | 2025 |
| Corex Transport & Logistics Ltd | Transport & logistics | 2026 |
| Corinacltd Limited | Administrative & support | 2025 |
| Corinth House Freehold Limited | Households | 2008 |
| Corinthu Services Ltd | Transport & logistics | 2019 |
| Corleone Famiglia Ltd | Hospitality | 2024 |
| Corline Store Ltd | Wholesale & retail | 2025 |
| Cornerstone Advisors Limited | Professional & scientific | 2009 |
| Cornerstone Investments UK Limited | Real estate | 2004 |
| Cornerstone Products Limited | Wholesale & retail | 2020 |
| Cornerstone Property Management(London) Ltd | Real estate | 2025 |
| Cornerstone Vehicle Services Limited | Wholesale & retail | 2026 |
| Cornerstones Business Services Limited | Administrative & support | 2026 |
| Corolla Gold Limited | Professional & scientific | 2020 |
| Coronation Square Grocery Ltd | Wholesale & retail | 2025 |
| Corp Facilities Limited | Administrative & support | 2022 |
| Corpinal IP Limited | Professional & scientific | 2024 |
| Corpolet Ltd | Real estate | 2020 |
| Corporate Capital Connect Ltd | Financial services | 2023 |
| Corporate Energy Services Limited | Administrative & support | 2019 |
| Corporate Finance Global Partners Limited | Financial services | 2010 |
| Corporate UK Services Limited | Administrative & support | 2019 |
| Corpus K Limited | Health & social care | 2016 |
| Corsent Systems Limited | Information & communication | 2017 |
| Corsican Limited | Real estate | 2026 |
| Cortekz Technologies Ltd | Information & communication | 2025 |
| Corvix Ltd | Wholesale & retail | 2025 |
| Corwan Investments Limited | Real estate | 2025 |
| Cosmic Design Plus Ltd | Construction | 2025 |
| Cosmic Painting Limited | Construction | 2024 |
| Cosmo Earn Limited | Wholesale & retail | 2025 |
| Cosmos Capsule Apartments Ltd | Real estate | 2023 |
| Cosmoteq Ltd | Information & communication | 2026 |