| CTS Solutions Limited | Construction | 2005 |
| Cube Interiors & Refurbishment Ltd | Construction | 2018 |
| Cubelle Ltd | Other services | 2025 |
| Cubent Ltd | Wholesale & retail | 2018 |
| Cubixsol Limited | Information & communication | 2024 |
| Cubronelle Limited | Health & social care | 2021 |
| Cuddles Private Limited | Wholesale & retail | 2022 |
| Cuedos Ltd | Information & communication | 2021 |
| Cuemark Limited | Extraterritorial | 2013 |
| Culina Investment Ltd | Real estate | 2025 |
| Culina ROC Ltd | Real estate | 2021 |
| Cullane Carpentry Ltd | Construction | 2019 |
| Cullinan Chauffeurs Ltd | Transport & logistics | 2021 |
| Culpepper Investments Limited | Professional & scientific | 2022 |
| Cultivating Stronger Success Ltd | Administrative & support | 2025 |
| Cumberland 83 Ltd | Real estate | 2024 |
| Cumberland Assets Ltd | Hospitality | 2023 |
| Cumbernauld Care Limited | Health & social care | 2020 |
| Cupal,Limited | Professional & scientific | 1909 |
| Cuppa Chaii (Slough) Ltd | Hospitality | 2025 |
| Cupping Massage Hijama Slough Ltd | Health & social care | 2023 |
| Cuprinol Limited | Professional & scientific | 1988 |
| Cure Health Care Services Limited | Health & social care | 2016 |
| Curious Bites Ltd | Hospitality | 2025 |
| Curly Top Ltd | Other services | 2025 |
| Curry Crush Ltd | Hospitality | 2023 |
| Curry Gardens (Burnham) Ltd | Hospitality | 2016 |
| Curzon Residential Ltd | Real estate | 2025 |
| Custom Craft Design Ltd | Wholesale & retail | 2026 |
| Custom SIM Racing Ltd | Administrative & support | 2023 |
| Customised Care Ltd | Hospitality | 2023 |
| Customs Gateway Solutions Limited | Transport & logistics | 2025 |
| Cusuma Technologies Limited | Information & communication | 2025 |
| CUT a Long Story Ltd | Information & communication | 2013 |
| CUT INX Ltd | Other services | 2018 |
| Cvilla Apartments Limited | Real estate | 2023 |
| Cvilla Limited | Real estate | 2022 |
| CW Glasgow Ltd | Hospitality | 2020 |
| CW Global Consulting Ltd | Professional & scientific | 2021 |
| CW Midlands Limited | Hospitality | 2022 |
| CWD (Holdings) Limited | Financial services | 2005 |
| Cwell Limited | Wholesale & retail | 2012 |
| Cwhair Services Ltd | Other services | 2025 |
| Cwmsaerbren LLP | | 2017 |
| CWS Media Limited | Information & communication | 2013 |
| Cyber 247 Technologies Ltd | Information & communication | 2019 |
| Cyber Wise Limited | Information & communication | 2022 |
| Cyberessentia Ltd | Information & communication | 2025 |
| Cybergoods Ltd | Construction | 2025 |
| Cyberpentesting Limited | Information & communication | 2024 |
| Cybersecurity Consultants Ltd | Information & communication | 2020 |
| Cybersupport Ltd | Information & communication | 2011 |
| Cyberwave Solutions Limited | Information & communication | 2017 |
| Cyclacel Limited | Professional & scientific | 1996 |
| CYM Consultancy Limited | Professional & scientific | 2022 |
| Cymm Consultancy Ltd | Professional & scientific | 2024 |
| Cypress Consultancy Limited | Professional & scientific | 2023 |
| Czarny Ltd | Transport & logistics | 2016 |
| Czech Beer Alliance UK Limited | Wholesale & retail | 2023 |
| D & D International Limited | Wholesale & retail | 2004 |
| D & J Beauty & Thai Spa Ltd | Other services | 2015 |
| D & Kris Limited | Transport & logistics | 2023 |
| D & O Nail Spa Ltd | Other services | 2016 |
| D & V Property and Investment Limited | Real estate | 2000 |
| D B Toilets Hire Ltd | Administrative & support | 2026 |
| D Bascombe Limited | Professional & scientific | 2013 |
| D Boghossian Ltd | Wholesale & retail | 2026 |
| D G Jones & Partners Limited | Extraterritorial | 2011 |
| D Gabuure Ltd | Wholesale & retail | 2025 |
| D Gurr Consultants Limited | Professional & scientific | 2018 |
| D M Logistics Limited | Transport & logistics | 2001 |
| D P T Limited | Construction | 2005 |
| D R Stores Ltd | Wholesale & retail | 2025 |
| D Riocco Ltd | Real estate | 2025 |
| D S Plumbing Heating & GAS Services Limited | Construction | 2025 |
| D S Roofing Solutions Ltd | Construction | 2023 |
| D Sonar Solutions Limited | Information & communication | 2014 |
| D&A Mgmt and Consulting Ltd | Wholesale & retail | 2019 |
| D&D Corporation Ltd | Wholesale & retail | 2002 |
| D&E Logistics Ltd | Transport & logistics | 2023 |
| D&G Property and Investment Ltd | Construction | 2009 |
| D&H Lexsys Limited | Information & communication | 2025 |
| D&Jtech Ltd | Information & communication | 2025 |
| D&N Cleaning Ltd | Administrative & support | 2025 |
| D&R Vision Builders Ltd | Construction | 2020 |
| D&T Services London Ltd | Transport & logistics | 2020 |
| D&Y Distribution Services Ltd. | Administrative & support | 2019 |
| D-Zack Ltd | Hospitality | 2020 |
| D. & S. Victory Ltd | Extraterritorial | 2014 |
| D. D.Wood Limited | Professional & scientific | 2017 |
| D. James Graham Electrical Ltd | Construction | 2018 |
| D.M. Elliot Carpentry Ltd | Construction | 2018 |
| D.W.Francis Limited | Construction | 2009 |
| D2H Solutions Limited | Wholesale & retail | 2009 |
| D4 Resource Solutions Ltd | Professional & scientific | 2010 |
| DA Capital Investments Ltd | Real estate | 2025 |
| DA Costa Health Care Limited | Health & social care | 2021 |
| DA K Rana Enterprise Ltd | Administrative & support | 2021 |
| DA Real Estates Ltd | Real estate | 2018 |
| DA Services Limited | Real estate | 2025 |