| Captain Group Kotli Ltd | Wholesale & retail | 2025 |
| Car and Van Breakdown Recovery Luton Ltd | Wholesale & retail | 2014 |
| Car Base MK Limited | Wholesale & retail | 2025 |
| Car Bucks Ltd | Wholesale & retail | 2025 |
| Car Firm Ltd | Wholesale & retail | 2014 |
| Car Force Ltd | Wholesale & retail | 2025 |
| Car Guys Bedfordshire Ltd | Transport & logistics | 2023 |
| Car Kraze Ltd | Wholesale & retail | 2025 |
| Car Lounge Limited | Wholesale & retail | 2015 |
| Car Point Luton Ltd | Wholesale & retail | 2018 |
| Car Selection Limited | Wholesale & retail | 2020 |
| Car Service Luton Ltd | Wholesale & retail | 2025 |
| Carapa Engineering Limited | Professional & scientific | 2024 |
| Carapa School of Operations and Maintenance Excellence Limited | Education | 2024 |
| Carbon Dream Ltd | Manufacturing | 2026 |
| Carbon Future Limited | Construction | 2020 |
| Carbon Sync Limited | Administrative & support | 2024 |
| CARBON60 Limited | Administrative & support | 1988 |
| Carbonology Ltd | Information & communication | 2022 |
| Carbune Handyman Ltd | Construction | 2025 |
| Cardiff MAK Ltd | Hospitality | 2024 |
| Care & Carry Limited | Transport & logistics | 2025 |
| Care 4 ALL Ltd | Health & social care | 2015 |
| Care Always Ltd | Health & social care | 2018 |
| Care and Safe Ltd | Administrative & support | 2024 |
| Care Masters Limited | Health & social care | 2026 |
| Care MORE24 Ltd | Administrative & support | 2025 |
| Care Scope Ltd | Public administration | 2021 |
| Care Unveil Ltd | Information & communication | 2026 |
| Care With Pride Ltd | Education | 2012 |
| CARE4PAEDS Limited | Administrative & support | 2021 |
| Carebridge Physiotherapy Ltd | Health & social care | 2025 |
| Carebuds Ltd | Wholesale & retail | 2026 |
| Careercraft Advisors Ltd | Manufacturing | 2025 |
| Careers YOU Love Ltd | Administrative & support | 2022 |
| Caregov Ltd | Professional & scientific | 2019 |
| Careon Staffing Ltd | Administrative & support | 2025 |
| CAREPATH24 Limited | Administrative & support | 2023 |
| Careplus DM Ltd | Administrative & support | 2016 |
| Carerstoday Ltd | Health & social care | 2017 |
| Carewell Health Services Ltd | Health & social care | 2025 |
| Carex Cleaning Ltd | Administrative & support | 2026 |
| Carget Ltd | Wholesale & retail | 2021 |
| Cargo Solutions Ltd | Transport & logistics | 2021 |
| Cargo Spot Ltd | Transport & logistics | 2024 |
| Cargo Warrior Logistics Limited | Transport & logistics | 2025 |
| Cargogrid Ltd | Wholesale & retail | 2025 |
| Caribo Limited | Real estate | 1995 |
| Caricare Transporto Ltd | Transport & logistics | 2017 |
| Caring Feathers Burton Limited | Health & social care | 2023 |
| Caring Feathers Ltd | Health & social care | 2021 |
| Caring Hands Home Care Ltd | Health & social care | 2026 |
| Caring Needs Limited | Health & social care | 2021 |
| Caring With Mandy Home Support Limited | Health & social care | 2025 |
| Carleigh Properties Ltd. | Real estate | 2012 |
| Carlisle Cleaning Services Holdings Limited | Administrative & support | 1992 |
| Carlisle Cleaning Services Limited | Administrative & support | 1989 |
| Carlisle Events Services Limited | Administrative & support | 2001 |
| Carlisle Group Limited | Professional & scientific | 1952 |
| Carlisle Interior Services Limited | Construction | 2001 |
| Carlisle Nominees Limited | Professional & scientific | 1997 |
| Carlisle Retail Services (Luton) Limited | Administrative & support | 1994 |
| Carlisle Security Services Limited | Administrative & support | 1991 |
| Carlisle Staffing Services Holdings Limited | Administrative & support | 2001 |
| Carlisle Staffing Services Limited | Administrative & support | 1993 |
| Carlisle Support Services Group Limited | Professional & scientific | 2011 |
| Carlton (Harpenden) Limited | Households | 1969 |
| Carlton Road Developers Limited | Real estate | 2025 |
| Carly Charles Limited | Households | 2024 |
| Carmela Homes Ltd | Real estate | 2026 |
| Carmenta Ltd | Professional & scientific | 2022 |
| Carnation Services Limited | Administrative & support | 2008 |
| Carnegie Dulwich Limited | Real estate | 2020 |
| Carnex Autos Ltd | Wholesale & retail | 2025 |
| Carnova Motors Limited | Wholesale & retail | 2026 |
| Carpets Craft Interiors Ltd | Wholesale & retail | 2013 |
| Carrington Property Management Ltd | Real estate | 2019 |
| Carroll & SON Ltd | Professional & scientific | 2015 |
| Carry on Luggage Ltd | Wholesale & retail | 2025 |
| Cars Site Ltd | Wholesale & retail | 2025 |
| CARS4U Autos Limited | Wholesale & retail | 2026 |
| Carslink Ltd | Wholesale & retail | 2024 |
| Carson Analysis Ltd | Information & communication | 2004 |
| Carszoo Ltd | Wholesale & retail | 2026 |
| Cart House Ltd | Wholesale & retail | 2026 |
| Cart Mash Limited | Wholesale & retail | 2016 |
| Cartermere Ltd | Wholesale & retail | 2025 |
| Carti Crestine Ltd | Wholesale & retail | 2019 |
| Cartverse Ltd | Wholesale & retail | 2025 |
| Cartwheel Consulting Limited | Professional & scientific | 2026 |
| Carville Properties Limited | Households | 2021 |
| Carwash Leagarve Ltd | Other services | 2023 |
| Carway INT Rental Ltd | Administrative & support | 2021 |
| Carzilla Ltd | Wholesale & retail | 2024 |
| Carzone Luton Limited | Wholesale & retail | 2025 |
| Carzone Motors Ltd | Wholesale & retail | 2024 |
| Carzuu Ltd | Wholesale & retail | 2024 |
| CAS Constructions Limited (Luton) Ltd | Construction | 2018 |
| CAS Legal Limited | Professional & scientific | 2019 |
| CAS Smart Estate Ltd | Real estate | 2025 |