| Cristinel Gheti Ltd | Construction | 2026 |
| Cristtrans Ltd | Transport & logistics | 2021 |
| Critical Care Working Ltd | Health & social care | 2020 |
| Critical Consulting Ltd | Information & communication | 2014 |
| Crlm Properties Limited | Construction | 2023 |
| CRM Home Improvements Limited | Construction | 2025 |
| CRM Plaster Limited | Construction | 2021 |
| Cromer Barber Limited | Other services | 2025 |
| Cromford Properties Limited | Construction | 1992 |
| Crompton Building & Development Limited | Real estate | 2020 |
| Crompton Joinery Limited | Construction | 1999 |
| Cromwell Hill Limited | Real estate | 2014 |
| Crop's & Partners UK Limited | Wholesale & retail | 2017 |
| Crop's Foods Ltd. | Wholesale & retail | 1989 |
| Cross City Limited | Other services | 2019 |
| Cross Country Transport Limited | Transport & logistics | 2015 |
| Cross Export Ltd | Wholesale & retail | 2017 |
| Crosslead Healthcare Ltd | Health & social care | 2022 |
| Crown Autoz Ltd | Wholesale & retail | 2024 |
| Crown Chapter Limited | Wholesale & retail | 2025 |
| Crown Consult & Logistics Limited | Professional & scientific | 2014 |
| Crown Hair Tech LLP | | 2017 |
| Crown Line Travel Ltd | Transport & logistics | 2025 |
| Crown of Glory Pentecostal International Church | Other services | 2020 |
| Crown Secure Ltd | Administrative & support | 2025 |
| Crown Services 2022 Ltd | Transport & logistics | 2022 |
| Crown VIP Chauffeurs Ltd | Transport & logistics | 2026 |
| Crowned Authority Clothing Limited | Wholesale & retail | 2016 |
| Crowned Investment Ltd | Real estate | 2021 |
| Crownfair Property Consultants Ltd | Real estate | 2026 |
| Crowngate Global Ltd | Wholesale & retail | 2025 |
| Crownport Ltd | Wholesale & retail | 2025 |
| Crownpound Security Systems Limited | Manufacturing | 1996 |
| Crownstone Group Ltd | Information & communication | 2025 |
| Crsm Consulting Ltd | Administrative & support | 2024 |
| Crtb Limited | Construction | 2009 |
| Cruiser Source Ltd | Wholesale & retail | 2022 |
| Crusty Foods Limited | Hospitality | 2025 |
| Cruts Project Ltd | Real estate | 2021 |
| Crypto Trapper | Education | 2023 |
| Crystal Accountancy and Tax Advisors Ltd | Professional & scientific | 2024 |
| Crystal Breath Ltd | Transport & logistics | 2021 |
| Crystal Business Advisors Ltd | Professional & scientific | 2025 |
| Crystal Cleaning Hub Ltd | Administrative & support | 2026 |
| Crystal Cleaning Luton Ltd | Other services | 2017 |
| Crystal House Investments Ltd | Real estate | 2024 |
| Crystal International London Ltd | Financial services | 2011 |
| Crystal Johnston Limited | Wholesale & retail | 2019 |
| Crystal Memorials Ltd | Wholesale & retail | 2015 |
| Crystal Property (Luton) Ltd | Real estate | 2017 |
| Crystal Sports London Ltd | Wholesale & retail | 2023 |
| Crystal Water Services Ltd | Water & waste | 2018 |
| Crystalz Limited | Wholesale & retail | 2025 |
| CS Acquisitions One Ltd | Financial services | 2024 |
| CS Block Management Ltd | Households | 2019 |
| CS Compliance Ltd | Professional & scientific | 2019 |
| CS Facades Ltd | Construction | 2024 |
| CS Lets Ltd | Real estate | 2016 |
| CS Mcintosh Ltd | Construction | 2022 |
| CS Online Innovations Ltd | Wholesale & retail | 2025 |
| CS Property Group Limited | Real estate | 2018 |
| CS Roberts Residential Ltd | Real estate | 2017 |
| CS Windows & Doors Ltd | Construction | 2018 |
| CS2 Exterior Systems Ltd | Construction | 2026 |
| CSG UK Limited | Administrative & support | 2003 |
| CSR Nexus Consulting Ltd | Extraterritorial | 2024 |
| Csuma Ltd | Construction | 2024 |
| Ctbspecialist Limited | Health & social care | 2019 |
| CTD Metals Ltd | Water & waste | 2022 |
| Ctdenterpriseuk Limited | Construction | 2022 |
| Ctdholding Limited | Construction | 2022 |
| Cted Ltd | Wholesale & retail | 2026 |
| CTL Trans Ltd | Transport & logistics | 2024 |
| CTL UK Trans Ltd | Transport & logistics | 2026 |
| CTM UK Services Ltd | Wholesale & retail | 2024 |
| Ctnkaya Ltd | Transport & logistics | 2021 |
| Ctrl Room (Online) Ltd | Information & communication | 2024 |
| Ctst Ltd | Information & communication | 2025 |
| CTU Properties Limited | Real estate | 2022 |
| Cube Consultants Ltd | Professional & scientific | 2023 |
| Cube Metals Ltd | Manufacturing | 2017 |
| Cube Mortgages Ltd | Financial services | 2022 |
| Cubic Wave Ltd | Professional & scientific | 2018 |
| Cubix Office Services Limited | Administrative & support | 2016 |
| Cubix Services Limited | Construction | 2019 |
| Cuckoos Property Ltd | Real estate | 2024 |
| Cudoweld Limited | Construction | 2026 |
| CUE Groop UK Ltd | Hospitality | 2012 |
| Culbeat Limited | Professional & scientific | 2011 |
| Cumberise Properties Ltd | Construction | 2022 |
| Cupac Solutions Limited | Health & social care | 2023 |
| Cupi ALB Construction Limited | Construction | 2021 |
| CUR8 Company (Services) Ltd | Other services | 2026 |
| Curlew Enterprises Ltd | Health & social care | 2018 |
| Curry Garden (Berkhamsted) Limited | Hospitality | 1999 |
| Curry Garden Eggington Ltd | Hospitality | 2014 |
| Curry Leaf Luton Ltd | Hospitality | 2018 |
| Curry M Ltd | Hospitality | 2020 |
| Curson Rochford LLP | | 2004 |
| Curtains and Linens Outlet Ltd | Wholesale & retail | 2015 |