| Cruz Control Limited | Financial services | 2025 |
| Cruze Financial Solutions Ltd | Financial services | 2019 |
| Crypto Dragon Limited | Financial services | 2023 |
| Crypto News Boost Services Ltd | Professional & scientific | 2025 |
| Cryptotax Consultants Ltd | Professional & scientific | 2021 |
| Cryptum Limited | Information & communication | 2005 |
| Crystal Clear Recruitment Ltd | Administrative & support | 2025 |
| Crystal Energy Supply Ltd | Manufacturing | 2025 |
| Crystal Gifts Limited | Wholesale & retail | 2024 |
| Crystal Gold (UK) Ltd | Wholesale & retail | 2013 |
| Crystalclear Optometry Ltd | Health & social care | 2025 |
| Crystallease Investments Ltd | Information & communication | 2024 |
| CS Prime Academy Ltd | Education | 2025 |
| CSC - Renovation Ltd | Construction | 2021 |
| CSF DRY Lining Ltd | Construction | 2017 |
| CSF Homes Ltd | Real estate | 2025 |
| CSJ Solutions Limited | Information & communication | 2013 |
| CSL (Dualcom) Limited | Manufacturing | 1996 |
| CSL Communications Group Limited | Professional & scientific | 2011 |
| CSL Dualcom Group Limited | Manufacturing | 2009 |
| CSL Entertainment Ltd | Hospitality | 2018 |
| CSL Practice Ltd | Professional & scientific | 2019 |
| Csnk Energy Limited | Professional & scientific | 2015 |
| CSO Projects & Surveying Ltd | Professional & scientific | 2025 |
| CSW Designs Limited | Professional & scientific | 2026 |
| Cswfd Ltd | Professional & scientific | 2022 |
| Ctech Network Services Limited | Information & communication | 2000 |
| CTM Consulting Services Ltd | Professional & scientific | 2016 |
| Ctmk Construction Ltd | Construction | 2023 |
| Cubicus Solutions Limited | Information & communication | 2026 |
| Cudahy Signs Ltd | Wholesale & retail | 2025 |
| Cullinans Cars Ltd | Wholesale & retail | 2025 |
| Culpin Consulting Limited | Information & communication | 2015 |
| Culture Chameleon Ltd | Administrative & support | 2019 |
| Culture Regeneration Associates Limited | Professional & scientific | 2005 |
| Culverlands Consulting Ltd. | Professional & scientific | 2016 |
| Culverlands Enterprises Limited | Information & communication | 2013 |
| Culverstone Stores Ltd | Wholesale & retail | 2005 |
| Cumberland Consulting Limited | Professional & scientific | 2009 |
| Cumby Irons Limited | Professional & scientific | 2018 |
| Cumnor Hurst | Agriculture & fishing | 2008 |
| Cunningham Park Properties Limited | Real estate | 2012 |
| Cupsy Ltd | Wholesale & retail | 2025 |
| Cura Spaces Limited | Administrative & support | 2021 |
| Curious Creators Limited | Professional & scientific | 2023 |
| Currall Lewis & Martin Limited | Extraterritorial | 1925 |
| Current Design Interiors Ltd | Construction | 2018 |
| Curry CUP Limited | Extraterritorial | 2013 |
| Cursillo Ltd | Information & communication | 2021 |
| Curtis and Partners Limited | Professional & scientific | 2015 |
| Custerdome Consulting Ltd | Construction | 2013 |
| Custodian Estates Ltd | Households | 2022 |
| Custodian Tax and Accountancy Services Limited | Professional & scientific | 2010 |
| Custom & Unique Limited | Construction | 2007 |
| Custom Audio Visual Limited | Extraterritorial | 2012 |
| Custom Enhance Ltd | Wholesale & retail | 2016 |
| CUT and Shutter Ltd | Information & communication | 2014 |
| CUT N Edge Limited | Manufacturing | 2009 |
| CUT Once Construction Ltd | Manufacturing | 2025 |
| Cutplay Ltd | Extraterritorial | 2001 |
| Cutting Edge Aviation Solutions Limited | Professional & scientific | 2006 |
| CVK Infotech Ltd | Information & communication | 2020 |
| CVL Beauty by Valerie Lawson Ltd | Other services | 2025 |
| CVM Lifting Ltd | Construction | 2019 |
| Cvor Services Ltd | Construction | 2026 |
| CVX Consulting Ltd | Information & communication | 2012 |
| CW Homes Limited | Real estate | 2014 |
| CW8 Communications UK Ltd | Professional & scientific | 2023 |
| Cwta Consulting Limited | Professional & scientific | 2010 |
| CX Stables Limited | Agriculture & fishing | 2024 |
| CX Studios Ltd | Information & communication | 2022 |
| Cyan Heart Limited | Education | 2017 |
| Cybedge Technologies Ltd | Information & communication | 2022 |
| Cyber Calls Ltd | Administrative & support | 2024 |
| Cyber Ciso Ltd | Information & communication | 2017 |
| Cyber Tactic Ltd | Information & communication | 2025 |
| Cyberassured Consultancy Ltd | Information & communication | 2025 |
| Cyberheads Ltd | Information & communication | 2020 |
| Cybersnoopz Ltd | Information & communication | 2022 |
| Cyberwise Labs Ltd | Information & communication | 2023 |
| CYM Ecom Ltd | Wholesale & retail | 2024 |
| Cynapps Limited | Information & communication | 2009 |
| Cyple Tree Ltd | Hospitality | 2024 |
| Cyroco LP | | 2017 |
| Cytex Ltd | Professional & scientific | 2012 |
| D & C Building Company Ltd | Construction | 2016 |
| D & D Double Cars PVT Ltd | Wholesale & retail | 2024 |
| D & D Drinks Catering Ltd | Professional & scientific | 2019 |
| D & M London Construction Ltd. | Construction | 2017 |
| D & R Property Investments Limited | Real estate | 2013 |
| D - Fine Leisure Limited | Hospitality | 2000 |
| D and J K Plumbing & Heating Ltd | Construction | 2021 |
| D J a Online Services Limited | Information & communication | 2010 |
| D Lawlor Consulting Ltd | Professional & scientific | 2025 |
| D Lightowler Services Limited | Professional & scientific | 2011 |
| D M Designs Solutions Limited | Professional & scientific | 2024 |
| D Property Maintenance Limited | Construction | 2024 |
| D S S Consulting Limited | Information & communication | 1999 |
| D Tiles Limited | Wholesale & retail | 2024 |
| D Traffic Management Limited | Construction | 2018 |