| Carami Ltd | Transport & logistics | 2016 |
| Caravannersrus Limited | Hospitality | 2014 |
| Carayol Consultants Limited | Administrative & support | 2023 |
| Carbon Causeway Ltd | Professional & scientific | 2025 |
| Carbon Chain Cyber (C3) Limited | Information & communication | 2018 |
| Carbon Harvesting Contracts Limited | Extraterritorial | 2007 |
| Carbon IQ Group Ltd | Administrative & support | 2025 |
| Carbon Neutral Infrastructure Limited | Professional & scientific | 2025 |
| Carden Park Hotel Limited | Hospitality | 2006 |
| CARDEN72 Limited | Construction | 2007 |
| Cardiff Geotechnical Ltd | Professional & scientific | 2019 |
| Cardiology Devices Ltd | Professional & scientific | 2021 |
| Cardmajor Limited | Real estate | 1997 |
| Cards Building Ltd | Construction | 2024 |
| Cardwell Park Residents Management Company Limited | Households | 2025 |
| Care Ascent Consulting Ltd | Administrative & support | 2026 |
| Care Correct Ltd | Health & social care | 2024 |
| Care Cosmetics Ltd | Other services | 2022 |
| Carehak Limited | Health & social care | 2023 |
| Carenzi Venues Limited | Arts & recreation | 2020 |
| Caresolve Financial Limited | Professional & scientific | 2016 |
| Caresolve Limited | Professional & scientific | 2014 |
| Carey Scientific Limited | Professional & scientific | 1998 |
| Carfico Limited | Financial services | 2017 |
| Carge Limited | Transport & logistics | 2019 |
| Cargo World Holdings Ltd | Financial services | 2025 |
| Cargo World Logistics Limited | Transport & logistics | 2018 |
| Cariad Productions Limited | Information & communication | 2025 |
| Carinthia Ltd | Professional & scientific | 2025 |
| Carlaw Project Services Limited | Administrative & support | 2026 |
| Carlex Limited | Wholesale & retail | 1946 |
| Carlin Trend Limited | Real estate | 2021 |
| Carlisle Southern Gateway Development Company Limited | Construction | 2007 |
| Carlogic Limited | Energy | 1993 |
| Carmandos MOT Ltd | Wholesale & retail | 2025 |
| Carmartrans Ltd | Transport & logistics | 2019 |
| Carmen Nicole Ltd | Other services | 2019 |
| Carol James Locum Services Ltd | Administrative & support | 2025 |
| Caroline Mackay Limited | Administrative & support | 2010 |
| Caroline's of Irlam Limited | Wholesale & retail | 2017 |
| Carolyn Stanhope Consulting Ltd | Administrative & support | 2026 |
| Carolysis Consulting Limited | Administrative & support | 2015 |
| Caroola Group Ltd | Professional & scientific | 2014 |
| Caroza Limited | Administrative & support | 2011 |
| Carpe Diem Commercial Ltd | Real estate | 2025 |
| Carpe Diem Incorporated Limited | Information & communication | 1999 |
| Carpe Diem Itln Limited | Health & social care | 2012 |
| Carpe Diem Portfolio Ltd | Financial services | 2026 |
| Carpe Diem Reim Ltd | Real estate | 2024 |
| Carr House Barn Management Company Limited | Hospitality | 1996 |
| Carr Stanley Limited | Professional & scientific | 2017 |
| Carraway Green (Management Company) Limited | Real estate | 2020 |
| Carreva Limited | Wholesale & retail | 2012 |
| Carriages Funeral Service Limited | Other services | 2022 |
| Carrier Transicold (UK) Limited | Wholesale & retail | 1972 |
| Carrington Garage Limited | Wholesale & retail | 2008 |
| Carrington Park Management Limited | Households | 2006 |
| Carrwood Group Limited | Financial services | 2022 |
| Carson Propco Ltd | Real estate | 2021 |
| Carson Property Ltd | Real estate | 2019 |
| Carter Clear Accounting Limited | Professional & scientific | 2021 |
| Carter Construction Services Limited | Administrative & support | 2018 |
| Carter Haulage Ltd | Transport & logistics | 2020 |
| Carters of Cheshire Ltd | Real estate | 2022 |
| Carters Project Solutions Limited | Professional & scientific | 2023 |
| Cartwright Commercial Refrigeration Ltd | Manufacturing | 2012 |
| Carty & Co Accountants Ltd | Professional & scientific | 2014 |
| CAS Accountants Limited | Professional & scientific | 2019 |
| CAS Building Projects Ltd | Construction | 2024 |
| CAS Piping Solutions Ltd | Professional & scientific | 2023 |
| Casa Global Group Limited | Professional & scientific | 2017 |
| Casa Global Sourcing Limited | Wholesale & retail | 2019 |
| Casa Mexica Limited | Hospitality | 2018 |
| Casa MSD Limited | Health & social care | 2025 |
| Casabona Limited | Information & communication | 2016 |
| Casamount Developments Limited | Construction | 2021 |
| Cascade Building Solutions Ltd | Construction | 2024 |
| Casey IT Limited | Information & communication | 2019 |
| Casiana Ltd | Transport & logistics | 2024 |
| Cask,Keg,Craft Dispense Services Limited | Administrative & support | 2018 |
| Caskam Ltd | Professional & scientific | 2020 |
| Caslogics Ltd | Professional & scientific | 2023 |
| Casmo Optimisation Limited | Information & communication | 2018 |
| Casper 16 Ltd | Transport & logistics | 2021 |
| Cass Creation Limited | Professional & scientific | 2023 |
| Cassian Scaffolding Services Ltd | Administrative & support | 2026 |
| Cassie Care Ltd | Health & social care | 2025 |
| Cassie Ford Limited | Administrative & support | 2024 |
| Castle Ecni 2 Limited | Professional & scientific | 2016 |
| Castle Finance (UK) Limited | Real estate | 2004 |
| Castle Security Limited | Professional & scientific | 2018 |
| Casualtop Limited | Real estate | 1995 |
| Cat-It Ltd | Information & communication | 2020 |
| Catalyst Change Limited | Professional & scientific | 2026 |
| Catalyst Choices Community Interest Company | Health & social care | 2014 |
| Catalyst Choices EBT Ltd | Professional & scientific | 2014 |
| Catalyst Choices Management Services Ltd | Professional & scientific | 2015 |
| CATALYST3 Ltd | Professional & scientific | 2023 |
| Catalytix Limited | Other services | 2018 |
| Catchtt Ltd | Real estate | 2024 |