| Carcaz Ltd | Real estate | 2009 |
| Card Network Solutions Limited | Information & communication | 2014 |
| Cardale Finance Limited | Financial services | 2019 |
| Cardamine Gardens Residents Management Company Limited | Households | 2020 |
| Cardcrusheruk Ltd | Wholesale & retail | 2025 |
| Carden and Sons Ltd | Other services | 2021 |
| Carden Engineering Limited | Manufacturing | 2012 |
| Cardiac Rhythm Management South Yorkshire Limited | Health & social care | 2023 |
| Cardiff Rugby Limited | Arts & recreation | 1996 |
| Cardigan Centre | Administrative & support | 1991 |
| Cardigan DRY Cleaners & Launderette Limited | Other services | 2023 |
| Cardigan Road (Developments) Limited | Administrative & support | 2001 |
| Cardinal Care Services Limited | Health & social care | 2016 |
| Cardinals Barber Limited | Other services | 2025 |
| Cardiotherapeutics Ltd | Health & social care | 2023 |
| Cardno Management Services Ltd | Administrative & support | 2018 |
| Cards Engineering Limited | Manufacturing | 2008 |
| Cardserv Ltd | Information & communication | 2018 |
| Cardus Property Ltd | Real estate | 2024 |
| Carduus Ltd | Professional & scientific | 2019 |
| Care & More Ltd | Arts & recreation | 2014 |
| Care 1ST Healthcare Services Ltd | Health & social care | 2020 |
| Care 24 Healthcare Ltd | Health & social care | 2025 |
| Care Accommodation Limited | Real estate | 2003 |
| Care Accountancy Ltd | Professional & scientific | 2010 |
| Care Accounts Ltd | Professional & scientific | 2022 |
| Care Compliance Solutions Ltd | Administrative & support | 2015 |
| Care Concern Yorkshire Ltd | Health & social care | 2010 |
| Care Cover Limited | Health & social care | 2014 |
| Care Craft Media Limited | Professional & scientific | 2026 |
| Care Financial Services Ltd | Financial services | 2020 |
| Care Global Healthcare Services Limited | Administrative & support | 2022 |
| Care Group Solutions Ltd | Administrative & support | 2025 |
| Care Growth Media Ltd | Professional & scientific | 2023 |
| Care Harbour Living Ltd | Health & social care | 2024 |
| Care Holdings Limited | Financial services | 2009 |
| Care Home Safeguarding Limited | Education | 2017 |
| Care Inclusive Limited | Health & social care | 2022 |
| Care Leavers Second Chance CIC | Education | 2025 |
| Care Maac Ltd | Manufacturing | 2024 |
| Care on Care Group Ltd | Health & social care | 2023 |
| Care on Care One Ltd | Health & social care | 2023 |
| Care Properties Ltd | Real estate | 2010 |
| Care Signature Christian Homecare Services Limited | Health & social care | 2016 |
| Care Technology Limited | Information & communication | 2016 |
| Care to Talk (Wakefield) CIC | Health & social care | 2024 |
| CARE247 Healthcare Services Ltd | Public administration | 2022 |
| Carebloom Healthcare Limited | Public administration | 2025 |
| Carebridge Support Services CIC | Health & social care | 2026 |
| Carebrix Solutions Ltd. | Administrative & support | 2025 |
| Carecompanion Plus CIC | Health & social care | 2025 |
| Carecraft Building Services Limited | Administrative & support | 2009 |
| CARED4 Leeds Ltd | Other services | 2017 |
| Career Days Limited | Administrative & support | 2020 |
| CAREERS4YEARS Ltd | Extraterritorial | 2024 |
| Careersinaudit.Com Limited | Administrative & support | 2005 |
| Caregroove Support Ltd | Health & social care | 2026 |
| Carekind Support and Staffing Ltd | Administrative & support | 2026 |
| Caremadeeasy Ltd | Information & communication | 2026 |
| Carenet Infocomm Ltd | Extraterritorial | 2023 |
| Careplus Recruitment Ltd | Health & social care | 2021 |
| Carers Leeds | Health & social care | 1996 |
| Caresmetics Ltd | Wholesale & retail | 2022 |
| Caretime Pharma Ltd | Wholesale & retail | 2023 |
| Careway Yorkshire Ltd | Health & social care | 2025 |
| CAREXTRA24/7 Healthcare Ltd | Health & social care | 2022 |
| Careyjones Chapmantolcher Limited | Financial services | 2010 |
| Carfill Fitment Centre Ltd | Wholesale & retail | 2023 |
| Caribbean Baskets Limited | Hospitality | 2024 |
| Caribbean Cricket Club C.I.C. | Education | 2023 |
| Carillion (AM) Limited | Professional & scientific | 1978 |
| Carillion Advice Services Limited | Professional & scientific | 2017 |
| Carillion AM Developments Limited | Administrative & support | 1982 |
| Carillion AM Government Limited | Construction | 1966 |
| Carillion Asset Management Limited | Construction | 1973 |
| Carillion Capital Projects Limited | Construction | 1930 |
| Carillion Construction (Contracts) Limited | Extraterritorial | 1919 |
| Carillion Construction (West Indies) Limited | Construction | 1966 |
| Carillion Construction Limited | Construction | 1957 |
| Carillion Construction Overseas Limited | Extraterritorial | 1976 |
| Carillion Energy Services Limited | Professional & scientific | 1999 |
| Carillion Fleet Management Limited | Other services | 1954 |
| Carillion Holdings Limited | Professional & scientific | 1999 |
| Carillion Integrated Services Limited | Other services | 1998 |
| Carillion JM Limited | Construction | 1903 |
| Carillion LGS Limited | Construction | 1996 |
| Carillion Mena Limited | Construction | 1945 |
| Carillion PLC | Construction | 1999 |
| Carillion Private Finance (Education) 2015 Limited | Administrative & support | 2015 |
| Carillion Private Finance Limited | Administrative & support | 1994 |
| Carillion Professional Services Limited | Professional & scientific | 1994 |
| Carillion Project Investments Limited | Professional & scientific | 1979 |
| Carillion Property Services Limited | Administrative & support | 2001 |
| Carillion Services 2006 Limited | Construction | 1992 |
| Carillion Services Limited | Administrative & support | 1995 |
| Carillion Specialist Services Limited | Professional & scientific | 1991 |
| Carillion Swindon Limited | Construction | 1988 |
| Carillion Utility Services Limited | Construction | 1962 |
| Carillion-Breathe Limited | Professional & scientific | 2013 |
| Carimed LLP | | 2024 |