| Capital Kinetics Limited | Financial services | 2017 |
| Capital Liquidity Markets Ltd | Information & communication | 2018 |
| Capital Manor Financial Advisors Limited | Financial services | 2003 |
| Capital Motor Company Limited | Extraterritorial | 2007 |
| Capital Motors Global Holdings Limited | Financial services | 2003 |
| Capital Private Finance Limited | Financial services | 2011 |
| Capital Project Management Limited | Professional & scientific | 2016 |
| Capitalclean Carry Limited | Transport & logistics | 2024 |
| Cappadocia Catering Ltd | Hospitality | 2026 |
| Capra Advisory Limited | Professional & scientific | 2025 |
| Capresio Limited | Wholesale & retail | 2025 |
| Caprinos Pizza Didcot Limited | Hospitality | 2024 |
| Caprinos Pizza Limited | Hospitality | 2014 |
| Caps Security Ltd | Administrative & support | 2004 |
| Capscorp Ltd | Professional & scientific | 2015 |
| Capstick Saxton Associates Limited | Professional & scientific | 2003 |
| Capt's Daughter Ltd | Wholesale & retail | 2025 |
| Captaingastro Ltd | Wholesale & retail | 2025 |
| Capybara Pond Ltd | Other services | 2025 |
| Capzas Limited | Information & communication | 2021 |
| Car and Van Service Station Limited | Wholesale & retail | 2008 |
| Car Doctor (MK) Ltd | Wholesale & retail | 2017 |
| Car FIX & Clean Service Limited | Wholesale & retail | 2026 |
| Car Geniee Limited | Wholesale & retail | 2025 |
| Car-Go Milton Keynes Ltd | Wholesale & retail | 2026 |
| Cara Networks Limited | Information & communication | 2001 |
| Carabosse Theatre Company C.I.C. | Arts & recreation | 2013 |
| Carberry Property LLP | | 2020 |
| Carbon Europe Ltd | Manufacturing | 2018 |
| Carbon Profile Limited | Other services | 2014 |
| Carbon Registry Services Limited | Information & communication | 2003 |
| Card Mansion Ltd | Information & communication | 2026 |
| Cardinal Industries Limited | Information & communication | 2025 |
| Cardinal Investment Properties Limited | Extraterritorial | 2012 |
| Cardos Construction Ltd | Construction | 2024 |
| Cardrew School Holding Limited | Construction | 2023 |
| Cardrew School Ltd | Construction | 2023 |
| Cardrew School Operations Limited | Education | 2023 |
| Cardroom Enterprises Limited | Information & communication | 2005 |
| Cards & Gifts in Stony Ltd | Wholesale & retail | 2025 |
| Care and Consult Limited | Professional & scientific | 2024 |
| Care Artisan Limited | Health & social care | 2022 |
| Care Focus Services Limited | Administrative & support | 2022 |
| Care for YOU MK Ltd | Health & social care | 2023 |
| Care Hands Limited | Health & social care | 2014 |
| Care MK Ltd | Health & social care | 2019 |
| Care Nest UK Ltd | Public administration | 2025 |
| Care Stabilizers Ltd | Health & social care | 2024 |
| Care Staff Recruitment Ltd | Health & social care | 2015 |
| Care Support MK Ltd | Health & social care | 2012 |
| Carebridge Healthcare Solutions Ltd | Health & social care | 2024 |
| Carechamps Ltd | Health & social care | 2018 |
| Caredent Limited | Health & social care | 2011 |
| Caredent Managements Limited | Real estate | 2016 |
| Career Consulting & Solutions Ltd | Administrative & support | 2020 |
| Career Network Limited | Education | 2026 |
| Carefreelushify Limited | Manufacturing | 2023 |
| Caregram Partners Ltd | Other services | 2023 |
| Carehelpline Ltd | Other services | 2010 |
| Careown Community Living Limited | Health & social care | 2023 |
| Careplus Integrated Services Ltd | Health & social care | 2026 |
| Cares&Co Limited | Wholesale & retail | 2023 |
| Carewise Services Ltd | Health & social care | 2025 |
| Carey Bastien Holdings Limited | Professional & scientific | 2019 |
| Carezone Health Services Ltd | Administrative & support | 2021 |
| Carf Europe | Health & social care | 2008 |
| Cargil Property Lettings Ltd | Real estate | 2026 |
| Cargo Solved Ltd | Transport & logistics | 2020 |
| Cargoflight Ltd | Other services | 2023 |
| Cargoking Solutions Ltd | Transport & logistics | 2020 |
| Cargreen Developments Limited | Manufacturing | 2017 |
| Carhub MK Ltd | Wholesale & retail | 2015 |
| Caring Beyond Ltd | Health & social care | 2025 |
| Caringminds Healthcare Ltd | Health & social care | 2025 |
| Caris Care Solutions Ltd | Health & social care | 2022 |
| Carisbrook Cars Ltd | Administrative & support | 2024 |
| Carl Vernon Coaching Ltd | Information & communication | 2019 |
| Carleton Investments Ltd | Households | 2011 |
| Carlo's Coffee Bar Limited | Hospitality | 2016 |
| Carlton Car Service Ltd | Transport & logistics | 2010 |
| Carlton People Consulting Ltd | Professional & scientific | 2026 |
| Carly Randall Limited | Administrative & support | 2019 |
| Carlyle Property Group Limited | Real estate | 2010 |
| Carmara Properties Ltd | Real estate | 2024 |
| Carmatt Limited | Transport & logistics | 2022 |
| Carmel Investments Ltd | Real estate | 2025 |
| Carmelite Property Limited | Professional & scientific | 2011 |
| Carmelo Alessi Hairdressing Limited | Other services | 2008 |
| Carmoose Ltd | Wholesale & retail | 2026 |
| Carnival Arts Development Milton Keynes CIC | Education | 2025 |
| Carol Williams Associates Ltd | Professional & scientific | 2018 |
| Carole Brooks Associates Limited | Professional & scientific | 2009 |
| Carole Matthews (INK) Limited | Arts & recreation | 2002 |
| Caroline Stead Ltd | Administrative & support | 2014 |
| Carolpeterous Limited | Information & communication | 2018 |
| CARP4LESS Limited | Wholesale & retail | 2016 |
| Carpet Factory Sales Limited | Wholesale & retail | 2002 |
| Carpet Klean Limited | Households | 2020 |
| Carpet MK Ltd | Construction | 2025 |
| Carpetwise (Europe) Limited | Wholesale & retail | 1993 |