| Cardip (UK) Ltd | Wholesale & retail | 2026 |
| Cards.Uk Ltd | Administrative & support | 2012 |
| Care & Carers Ltd | Health & social care | 2017 |
| Care Beyond Ltd | Health & social care | 2024 |
| Care Business Hub Ltd | Professional & scientific | 2024 |
| Care Harmony Solutions Limited | Health & social care | 2011 |
| Care Professionals 24 Limited | Health & social care | 2023 |
| Care to Thrive Ltd | Wholesale & retail | 2020 |
| Care Yolanda Limited | Health & social care | 2018 |
| Careberry Software Ltd | Information & communication | 2020 |
| Career Game AI Limited | Education | 2026 |
| Careflow AI Ltd | Information & communication | 2026 |
| Carella Logistics Limited | Transport & logistics | 2023 |
| Carers Trust Bucks and Milton Keynes | Health & social care | 2003 |
| Carewellgroup Limited | Health & social care | 2024 |
| Carherts Limited | Wholesale & retail | 2019 |
| Caribbean Community Lunch Club CIC | Hospitality | 2023 |
| Caribbean Cravings Ltd | Wholesale & retail | 2023 |
| Carington Ltd | Administrative & support | 2025 |
| Carl Cropper Consulting Limited | Administrative & support | 2016 |
| Carlton Consultancy Limited | Professional & scientific | 1997 |
| Carm Clothing Ltd | Wholesale & retail | 2026 |
| Carmel's Limited | Mining & quarrying | 2002 |
| Carmels Consulting Limited | Information & communication | 2025 |
| Carmels Fabrication Limited | Manufacturing | 2022 |
| Carmels Group Limited | Financial services | 2020 |
| Carmels Precision Limited | Professional & scientific | 2020 |
| Carmels Property Limited | Real estate | 2021 |
| Carnegie Manning Property Limited | Real estate | 2017 |
| Carol Jenkins Limited | Information & communication | 2002 |
| Carolyn Croucher Limited | Health & social care | 2010 |
| Carpentry by F.S Ltd | Manufacturing | 2024 |
| Carrageen Consulting Ltd | Professional & scientific | 2019 |
| Carrera Estates Limited | Real estate | 1988 |
| Carrera House Services Limited | Professional & scientific | 2016 |
| Carrera Property Ltd | Households | 2025 |
| Cartconnect Ltd | Wholesale & retail | 2024 |
| Carter Autocare Limited | Wholesale & retail | 2024 |
| Carter Collins Group Ltd | Financial services | 2020 |
| Carterwise Property Group Ltd | Real estate | 2025 |
| Carver Hill Properties Ltd | Real estate | 2025 |
| Carwithen Close (Management Company) Limited | Households | 2021 |
| Carznow Ltd | Wholesale & retail | 2025 |
| Casa Cossey Ltd | Hospitality | 2020 |
| Casa Roda Ltd | Wholesale & retail | 2022 |
| Casa Terra Ltd | Wholesale & retail | 2017 |
| Cash & Cheque Express Limited | Financial services | 2012 |
| Cassio Cleaning Limited | Administrative & support | 2022 |
| Castle Court Residents Association Limited | Households | 1969 |
| Castle Mount Freehold Ltd | Real estate | 2025 |
| Castle Mount Properties Ltd | Real estate | 2016 |
| Castle Park Accountants Ltd | Administrative & support | 2017 |
| Castleguard Ellice Limited | Real estate | 2021 |
| Castleguard Homes Limited | Construction | 2016 |
| Castleguard Shernhall ST Limited | Construction | 2015 |
| Castlewhite Solutions Limited | Information & communication | 2009 |
| Castra Solutions Ltd | Information & communication | 2021 |
| Caswell Maintenance Services Limited | Construction | 1987 |
| Caswell Residential Ltd | Real estate | 2026 |
| Cat Flap Media Ltd | Information & communication | 2015 |
| Cat Street Green Limited | Real estate | 2011 |
| Cat Underfloor Heating Ltd | Construction | 2024 |
| Catali London Limited | Wholesale & retail | 2014 |
| Catera.Uk Ltd | Professional & scientific | 2025 |
| Cathy Gallagher & Associates Limited | Professional & scientific | 2013 |
| Catlett Properties Limited | Real estate | 2020 |
| Cattleman Foods Ltd | Manufacturing | 2025 |
| Cawdell Contracts Limited | Construction | 2002 |
| Caxton House (Cambourne) Management Company Limited | Real estate | 2005 |
| Cayrel Investments Limited | Real estate | 2020 |
| CAZ Brain Limited | Information & communication | 2025 |
| CB Battery Limited | Energy | 2022 |
| CBB SPV Limited | Energy | 2024 |
| CBF Construction Ltd | Construction | 2022 |
| Cblp Management Ltd | Real estate | 2024 |
| Cbmb Limited | Information & communication | 2017 |
| CBR Consultancy Ltd | Professional & scientific | 2015 |
| CBS Plumbing & Heating Ltd | Construction | 2023 |
| CC Aluminium Frames Limited | Manufacturing | 2021 |
| CCB Services Limited | Construction | 2018 |
| CCL Aylesbury Limited | Transport & logistics | 2003 |
| CCL Derby Limited | Transport & logistics | 1993 |
| CCL Export Packing Limited | Administrative & support | 1999 |
| CCL Mechanical Services Ltd | Construction | 2017 |
| CDE Products Ltd | Manufacturing | 2012 |
| Ceai Ltd | Administrative & support | 2021 |
| Cecmopri Limited | Real estate | 2023 |
| Ceda Electrical Services Ltd | Construction | 2023 |
| Cedar House Solutions Limited | Information & communication | 2014 |
| Cedar Park Tree Care Ltd | Administrative & support | 2021 |
| Cedar River Developments Limited | Administrative & support | 2010 |
| Cedar Technologies (1997) Limited | Wholesale & retail | 1997 |
| Cedar Technologies (Holdings) Limited | Wholesale & retail | 2000 |
| Ceena Global Ltd | Wholesale & retail | 2025 |
| Celcis Limited | Professional & scientific | 2008 |
| Celebrities Jewellery Confectionery Gift Shop Ltd | Wholesale & retail | 2025 |
| Celeiro Church Ltd | Other services | 2026 |
| Celestialservices Ltd | Health & social care | 2013 |
| CELL2 Limited | Wholesale & retail | 2009 |
| Cement Business Advisory Ltd | Professional & scientific | 2015 |