| CU Bulk Removals Limited | Water & waste | 2018 |
| Cube Interactive Ltd | Information & communication | 2005 |
| Cubel Culture & Education Liaison ( UK ) Ltd | Education | 2012 |
| Cubexr Ltd | Information & communication | 2026 |
| Cubic Cooling Limited | Manufacturing | 2013 |
| Cubic Empire Ltd | Wholesale & retail | 2026 |
| CUBIC7 Ltd | Information & communication | 2017 |
| Cubicstone Tax Services Limited | Other services | 2020 |
| Cubrex Ltd | Real estate | 2019 |
| Cuddle Corner Limited | Wholesale & retail | 2025 |
| Cuddleshare Limited | Information & communication | 2024 |
| Cuddy Properties Ltd | Real estate | 2020 |
| CUE Global Advisory Ltd. | Professional & scientific | 2017 |
| CUE Global Properties Ltd. | Real estate | 2018 |
| Cued Ltd | Information & communication | 2022 |
| Cuffley Court Freehold Company Limited | Households | 2007 |
| CUI Xiaolin Limited | Wholesale & retail | 2023 |
| Cuil Burn Hydropower Ltd | Energy | 2019 |
| CUL Academy Trust Limited | Education | 2012 |
| Culex Limited | Wholesale & retail | 2025 |
| Culinary Health Ltd | Hospitality | 2016 |
| Cullen and Sons Limited | Construction | 2025 |
| Cullion Homes Ltd | Construction | 2016 |
| Cully & Co. Project Management Ltd | Construction | 2019 |
| Cultcare Ltd | Health & social care | 2024 |
| CULTIV8TIV Limited | Information & communication | 2023 |
| Cultivating Solutions Limited | Professional & scientific | 2023 |
| Cultural Reset Ltd | Hospitality | 2025 |
| Culture Africaine Ltd | Wholesale & retail | 2021 |
| Culture Club Training Limited | Education | 2026 |
| Cultvr Ltd | Arts & recreation | 2023 |
| Culver Financial Limited | Professional & scientific | 2023 |
| Culver Holdings Limited | Other services | 2023 |
| Culver Limited | Information & communication | 2026 |
| Cumbria Park Ltd | Hospitality | 2018 |
| Cummings (Civil Engineering) Ltd | Construction | 2021 |
| Cummins Land & Tree Care Ltd | Administrative & support | 2026 |
| Cumra Ltd | Manufacturing | 2021 |
| Cunningham Media Limited | Other services | 2017 |
| Cuore Ltd | Manufacturing | 2022 |
| Cuowbk Mart Ltd | Wholesale & retail | 2025 |
| CUP of Casa Limited | Hospitality | 2025 |
| Cupid Peptide Company Limited | Manufacturing | 2012 |
| Cupping GUY Ltd | Health & social care | 2022 |
| Cups of Healing Ltd | Wholesale & retail | 2024 |
| Cupscom Limited | Manufacturing | 2017 |
| Curamicus Ltd | Information & communication | 2015 |
| Curated Moments Ltd | Hospitality | 2023 |
| Curated Technologies Limited | Information & communication | 2025 |
| Curated Vintage Limited | Wholesale & retail | 2025 |
| Curative Cupping Limited | Health & social care | 2016 |
| Curauk Limited | Other services | 2020 |
| Curbism Ltd | Information & communication | 2025 |
| Curdworth Limited | Hospitality | 2021 |
| Cure IT Roofing Systems Ltd | Professional & scientific | 2020 |
| Curia Corporate Finance Limited | Professional & scientific | 2009 |
| Curiosity Kills Limited | Information & communication | 2013 |
| Curious Inklings Ltd | Arts & recreation | 2021 |
| Curious Tech Ltd | Wholesale & retail | 2019 |
| Curran Wealth Management Ltd | Financial services | 2011 |
| Current Euro System Ltd | Information & communication | 2025 |
| Current Ground Limited | Information & communication | 2025 |
| Curry & Sons Ltd | Construction | 2026 |
| Curry Club Wolverhampton Ltd | Hospitality | 2024 |
| Curry Island Ltd | Administrative & support | 2018 |
| Cursa Solutions Ltd | Administrative & support | 2021 |
| Cursum Perficio Ltd | Real estate | 2020 |
| Curtis and Sons Trading Limited | Wholesale & retail | 2025 |
| Curtis Jones Ltd | Other services | 2012 |
| Curtis Morris Limited | Wholesale & retail | 2025 |
| Curtis Richfield Holdings Ltd | Professional & scientific | 2017 |
| Curtz Ltd | Arts & recreation | 2017 |
| Curve Bar Ltd | Hospitality | 2025 |
| Curvolt Ltd | Professional & scientific | 2024 |
| Cushion Connection Ltd | Manufacturing | 2019 |
| Custard INK Ltd | Information & communication | 2020 |
| Custom Computer Services (Wales) Limited | Information & communication | 1997 |
| Custom Cooling Solutions Ltd | Energy | 2022 |
| Custom Design & Construction (Sussex) Ltd | Construction | 2017 |
| Custom Design Ltd T/A DVC Ltd | Administrative & support | 2017 |
| Custom House Project Ltd | Real estate | 2018 |
| Custom Knives Shop Ltd | Wholesale & retail | 2024 |
| Custom Mylars and Jars Ltd | Manufacturing | 2025 |
| Custom Signs Shop Limited | Wholesale & retail | 2024 |
| Customer Start Limited | Administrative & support | 2022 |
| Customfirst Property Management Limited | Hospitality | 1992 |
| Customised Luxury Furniture Ltd | Construction | 2015 |
| Customised Project Solutions Limited | Manufacturing | 2014 |
| Custoros | Professional & scientific | 2025 |
| Cutaway Consulting Ltd | Professional & scientific | 2018 |
| Cutest Systems Limited | Professional & scientific | 1984 |
| Cutting Edge Brides Limited | Administrative & support | 2010 |
| Cuziro UK Ltd | Transport & logistics | 2016 |
| Cv's and Career Transitions Ltd | Professional & scientific | 2016 |
| CVA Logistics and Transport Limited | Transport & logistics | 2019 |
| CVB Limited | Health & social care | 2019 |
| CVILLAGEE15 Ltd | Wholesale & retail | 2018 |
| Cvmc Global Limited | Professional & scientific | 2007 |
| Cvrunway Ltd | Wholesale & retail | 2021 |
| CW Bristol Benefits Ltd | Administrative & support | 2022 |