| Cool Group Ltd | Professional & scientific | 2017 |
| Cooprex Digital Ltd | Administrative & support | 2025 |
| Copper Beech Avenue Ltd | Households | 2016 |
| Copperfield Electrical Services Limited | Construction | 2025 |
| Copy Quality Holdings Limited | Financial services | 2023 |
| Copy Quality UK Ltd. | Manufacturing | 2015 |
| Coralmead Consultancy Ltd | Administrative & support | 2013 |
| Coren Foods Limited | Wholesale & retail | 2011 |
| Corner Stones Properties Development Limited | Real estate | 2026 |
| Cornflower Properties Limited | Real estate | 1972 |
| Corsto Ltd | Financial services | 2014 |
| Corsto Web Design Ltd | Information & communication | 2016 |
| Cortes Gifts Limited | Wholesale & retail | 2015 |
| CORYLUS365 Limited | Administrative & support | 2023 |
| Cosmeticampus Ltd | Professional & scientific | 2023 |
| Costs Lawyers Recruitment Agency Ltd | Administrative & support | 2025 |
| Costs Services I LLP | | 2019 |
| Costs Services II LLP | | 2019 |
| Costs Services III LLP | | 2019 |
| Costs Services IV LLP | | 2022 |
| Cougar Group Developments Limited | Professional & scientific | 2008 |
| Cougar Group Investments Limited | Professional & scientific | 2008 |
| Cougar Management Limited | Professional & scientific | 2008 |
| Couriers of Essex Ltd | Transport & logistics | 2025 |
| Course 2 Certify Ltd | Wholesale & retail | 2022 |
| Courtside London Limited | Arts & recreation | 2025 |
| Cousins Chauffeurs Ltd | Transport & logistics | 2025 |
| Coveley Consulting Limited | Professional & scientific | 2024 |
| Covenant Collaborations Ltd | Wholesale & retail | 2019 |
| Covie Group Ltd | Professional & scientific | 2017 |
| Cowardly Seagull Ltd | Arts & recreation | 2025 |
| COX Cleaning Limited | Administrative & support | 2023 |
| Cozz Limited | Hospitality | 2016 |
| Cozzio Limited | Hospitality | 2019 |
| CP Growth Ltd | Professional & scientific | 2023 |
| CP Sales Consultancy Ltd | Administrative & support | 2026 |
| CPL Carpentry Ltd | Construction | 2015 |
| Crabtree Corner Compliance Limited | Financial services | 2016 |
| Crace Building Contractors Ltd | Professional & scientific | 2016 |
| Cranleigh Accident Repair Services Ltd | Wholesale & retail | 2022 |
| Crazy Razor CUT Ltd | Other services | 2023 |
| Crazy Razor VIP Ltd | Other services | 2023 |
| Creams Najm LLP | | 2022 |
| Create That Post Ltd | Manufacturing | 2022 |
| Creating Stories Limited | Administrative & support | 2019 |
| Creative Catalyst Limited | Information & communication | 2021 |
| Creative Landscapes Maintenance Ltd | Administrative & support | 2017 |
| Creator Leaders Ltd | Administrative & support | 2025 |
| Creavo Limited | Information & communication | 2021 |
| Crescent Inns Ltd | Hospitality | 2023 |
| Crick Ltd | Real estate | 2017 |
| Crimp Hydraulic Services Limited | Manufacturing | 1983 |
| Cripsey Avenue Management (Hastingwood Court) Limited | Households | 1985 |
| Crispin Court Freehold Limited | Households | 1991 |
| Crispy Music Limited | Other services | 1999 |
| CRM Superstars Limited | Administrative & support | 2012 |
| CRM Team Global Limited | Information & communication | 2012 |
| CRM Team Holdings Limited | Financial services | 2017 |
| Crm.Team a Limited | Administrative & support | 2025 |
| CRN Contracts Ltd | Construction | 2021 |
| Croft END Developments Limited | Real estate | 2024 |
| Croft END Management Company Ltd | Real estate | 2026 |
| Cross Financial Training Limited | Education | 2016 |
| Crown & Sceptre Ltd | Hospitality | 2022 |
| Crown Aviation Limited | Transport & logistics | 2008 |
| Crown Security Guarding Ltd | Administrative & support | 2023 |
| Crown Vault Property Ltd | Real estate | 2026 |
| CRT Automotive Ltd | Transport & logistics | 2015 |
| CRT Performance Cars Ltd | Wholesale & retail | 2020 |
| Crucible of OIL Limited | Wholesale & retail | 2025 |
| CS Cardtronics Ltd | Administrative & support | 2025 |
| CS Marcelle Ltd | Real estate | 2021 |
| CS Safety Systems Ltd | Administrative & support | 2018 |
| CS Solutions 1995 Limited | Education | 2017 |
| CS Support Services Limited | Information & communication | 2016 |
| CSP Care Services Limited | Construction | 2015 |
| CSS 1995 Ltd | Administrative & support | 2025 |
| Ctb&N Property Management Ltd | Real estate | 2018 |
| CTL Management Limited | Wholesale & retail | 2013 |
| Ctrl Compliance Limited | Professional & scientific | 2025 |
| Ctrp Ltd | Construction | 2019 |
| Cubic One Investments Ltd | Real estate | 2021 |
| Cubic One Property Services Ltd | Households | 2025 |
| Cunningham Publishing Services Ltd | Information & communication | 2021 |
| Curly Tailed Monkey Ltd | Administrative & support | 2022 |
| Custom Home Cleaning Limited | Administrative & support | 2023 |
| Custom Lofts and Extensions Ltd | Construction | 2008 |
| Custom Steel Innovation Limited | Manufacturing | 2011 |
| Customerx World Limited | Information & communication | 2025 |
| CWG Goldsmith Asset Management Limited | Real estate | 2023 |
| CWT Enterprise Ltd | Wholesale & retail | 2024 |
| D & M Dzialo Services International Ltd | Administrative & support | 2019 |
| D and C Property Rentals Limited | Real estate | 2020 |
| D B FOX Limited | Construction | 2023 |
| D Hayes Construction Limited | Construction | 2023 |
| D Lynch Construction Ltd | Construction | 2018 |
| D Miller Holdings Ltd | Financial services | 2023 |
| D N M Systems Limited | Information & communication | 2008 |
| D N Property Services Ltd | Real estate | 2016 |
| D Powell GAS Ltd | Construction | 2026 |