| Chris Gaze Associates Ltd | Professional & scientific | 2022 |
| Chris Paine Physio Ltd | Health & social care | 2021 |
| Chris Self Motorcycles Limited | Wholesale & retail | 2002 |
| Chrissian Residential Home Limited | Health & social care | 2002 |
| Christchurch Group Ltd | Construction | 2025 |
| Christchurch Holland (New Homes) Limited | Real estate | 2018 |
| Christchurch Holland Concierge Ltd | Transport & logistics | 2021 |
| Christchurch Land & Estates (Elmswell South) Ltd | Real estate | 2015 |
| Christchurch Land & Estates (Felixstowe) Ltd | Households | 2014 |
| Christchurch Land Acquisition & Development Ltd | Real estate | 2014 |
| Christchurch Land Ltd | Real estate | 2011 |
| Christchurch Mortgage Solutions Limited | Financial services | 2015 |
| Christchurch Property Company Limited | Real estate | 1999 |
| Christchurch Solicitors LLP | | 2011 |
| Christchurch Veterinary Centre Limited | Professional & scientific | 2006 |
| Christian Allum Electrical Limited | Construction | 2022 |
| Christian Edward Property Limited | Real estate | 2020 |
| Christian Jesse Properties Ltd | Real estate | 2022 |
| Christlieb Capital UK Ltd | Wholesale & retail | 2008 |
| Christopher Harrall Associates Limited | Professional & scientific | 2014 |
| Christopher Nall Design Limited | Professional & scientific | 2003 |
| Chromalloy Holding II Limited | Professional & scientific | 2023 |
| Chromalloy Metal Tectonics Limited | Professional & scientific | 1980 |
| Chromalloy UK Holdings Ltd | Financial services | 2007 |
| Chromalloy United Kingdom Limited | Manufacturing | 1970 |
| Chronicle Community Story Projects CIC | Information & communication | 2018 |
| Chronicle Digital Storytelling Ltd | Administrative & support | 2015 |
| Church Farm (Drayton) Management Company Limited | Households | 2022 |
| Church Farm Place Management Company Limited | Real estate | 2017 |
| Church View (Bramford) Management Company Limited | Households | 2023 |
| Churchbase Ltd | Information & communication | 2026 |
| Churchgates 2000 Limited | Real estate | 2000 |
| Churchill Catering Limited | Hospitality | 1996 |
| Churchmanor (Huntingdon) Limited | Real estate | 1999 |
| Churchmanor Asset Management Limited | Real estate | 2010 |
| Churchmanor Holdings Limited | Real estate | 2010 |
| Churchmanor Limited | Real estate | 1985 |
| Churchmanor Property Company Limited(The) | Real estate | 1984 |
| Churncross Limited | Real estate | 1987 |
| Chutneyz Ltd | Hospitality | 2017 |
| CIB Consulting Limited | Administrative & support | 2024 |
| Cibulskis Limited | Transport & logistics | 2025 |
| Cicero Communications Ltd | Administrative & support | 2012 |
| Cidem Limited | Real estate | 2006 |
| Cifco Capital Limited | Real estate | 2017 |
| CIM Orphanage International CIC | Health & social care | 2025 |
| Cimr Ltd | Administrative & support | 2023 |
| Ciobanu Holdings Ltd. | Other services | 2025 |
| Cionet UK Limited | Administrative & support | 2017 |
| Cip&Ius Ltd | Transport & logistics | 2024 |
| Circelli N & Co Limited | Other services | 2017 |
| Circlon OIL and Energy Ltd | Water & waste | 2026 |
| Circoil Ltd. | Water & waste | 2024 |
| Circuit 369 Limited | Construction | 2018 |
| Circuit Technologies Ltd | Information & communication | 2026 |
| Circular Exchange Limited | Information & communication | 2026 |
| Cite Investments Limited | Financial services | 2009 |
| Cited Property Asset Management Limited | Real estate | 2025 |
| Cited Property Limited | Real estate | 2021 |
| Citosoft Ltd | Information & communication | 2025 |
| Citra Lokesh Limited | Administrative & support | 2021 |
| Citrus Wealth Management Limited | Financial services | 2005 |
| City Dining Contracts Limited | Hospitality | 2018 |
| City Friend Chinese Takeaway Ltd | Hospitality | 2024 |
| City Group Security Limited | Administrative & support | 1993 |
| City Vending Services Limited | Hospitality | 2002 |
| Cityflow Logistics Ltd | Extraterritorial | 2026 |
| CIVIC306 Limited | Financial services | 2023 |
| Civix Innovation Ltd | Construction | 2026 |
| Ciwan (Ipswich) Ltd | Other services | 2025 |
| CJ Electrical Contracting Services Limited | Construction | 2016 |
| CJ Frost Transport Ltd | Transport & logistics | 2025 |
| CJ Groundwork & Civil Engineering Ltd | Construction | 2020 |
| CJ Group Services Limited | Financial services | 2020 |
| CJ Plumbing & Heating Ltd | Construction | 2012 |
| CJ Transport Services Ltd | Transport & logistics | 2023 |
| Cjbfit Ltd | Arts & recreation | 2021 |
| CJK Music Limited | Administrative & support | 2012 |
| CJL Estates Ltd | Real estate | 2024 |
| CJL SPV1 Limited | Financial services | 2024 |
| CJM Carpentry & Joinery Ltd | Construction | 2013 |
| Cjwpilates+ Ltd | Other services | 2025 |
| CKL Ventures Ltd | Hospitality | 2012 |
| CKR Digital Limited | Information & communication | 2026 |
| Ckts Electrical Limited | Construction | 2022 |
| Claim Market Ltd | Professional & scientific | 2025 |
| Claimgrid Ltd | Professional & scientific | 2025 |
| Clair Pyper Consulting Limited | Professional & scientific | 2012 |
| Claire Bees Healthcare Ltd | Health & social care | 2018 |
| Clara Bowe Ltd | Manufacturing | 2015 |
| Clara Jane Ltd | Manufacturing | 2026 |
| Clara Rose Consultancy Ltd | Administrative & support | 2014 |
| Clare Court (Ipswich) Limited | Real estate | 2008 |
| Clarence EMP Limited | Real estate | 2023 |
| Claret Commercial Ltd | Financial services | 2026 |
| Claridge and Grace Ltd | Administrative & support | 2020 |
| Clarifi Consulting Ltd | Health & social care | 2008 |
| Clarity Industrial Marketing Ltd | Information & communication | 2020 |
| Clarity Stack Limited | Professional & scientific | 2018 |
| Clarity Umbrella Ltd | Administrative & support | 2019 |