| Constantia Management Limited | Administrative & support | 1996 |
| Constantin Chivu Ltd | Manufacturing | 2025 |
| Constantin Mihai Ltd | Manufacturing | 2025 |
| Constat Developments Limited | Construction | 2012 |
| Consteff UK Ltd | Wholesale & retail | 2025 |
| Constellation Housing Ltd | Construction | 2026 |
| Constellation Park Limited | Real estate | 2015 |
| Constellation Properties Ltd | Real estate | 2026 |
| Construct Building Services Limited | Construction | 2021 |
| Construction Assessments and Surveys Ltd | Professional & scientific | 2024 |
| Construction Associates Limited | Construction | 2024 |
| Construction Industry Limited | Construction | 2020 |
| Construction Plant Installations Limited | Construction | 2021 |
| Consult NT Ltd | Extraterritorial | 2019 |
| Consultant Secretarial Limited | Administrative & support | 2019 |
| Consultants for Global Education Ltd | Professional & scientific | 2019 |
| Consultap Limited | Administrative & support | 2024 |
| Containerit Limited | Transport & logistics | 2018 |
| Contento Pilates Ltd | Arts & recreation | 2025 |
| Contera Ltd | Manufacturing | 2021 |
| Continuations Limited | Information & communication | 2019 |
| Contour Communications Limited | Professional & scientific | 2011 |
| Contra Management Company (Clifton) Limited | Households | 2004 |
| Contract Flooring Services (Cambridge) Limited | Construction | 2004 |
| Contract Roofing Ltd | Construction | 2018 |
| Contracting International Services Ltd | Administrative & support | 2021 |
| Contractors Machinery Limited | Wholesale & retail | 1983 |
| Control Facilities Management Ltd | Administrative & support | 2024 |
| Conundrum Industrial Limited | Information & communication | 2018 |
| Converge Business Telecoms Limited | Information & communication | 2011 |
| Convincible Ltd | Professional & scientific | 2021 |
| Conway Software Ltd | Information & communication | 2021 |
| Cooba Limited | Information & communication | 2022 |
| Cook & Cook Construction Ltd | Construction | 2012 |
| Cook & Cook Consultancy Limited | Construction | 2017 |
| Cook & Tycer Ltd | Construction | 2002 |
| Cook 4 U Chinese Limited | Hospitality | 2025 |
| Cook's BBQ Company Ltd | Hospitality | 2026 |
| Cooke Curtis & Co Property Limited | Real estate | 2021 |
| Cooke Property Group Ltd | Real estate | 2022 |
| Cookie CUT Media Ltd | Information & communication | 2020 |
| Cool Cool Ltd | Hospitality | 2025 |
| Cool Grey 5 Ltd | Professional & scientific | 2012 |
| Cool Property GMB Limited | Real estate | 2024 |
| Cool Property Limited | Real estate | 2024 |
| Coolster International Trading Co., Ltd | Manufacturing | 2019 |
| Coolyoubest Limited | Information & communication | 2020 |
| Coombs Technologies Limited | Manufacturing | 2025 |
| Cooper Barnes Holdings Limited | Financial services | 2023 |
| Cooper Barnes Limited | Wholesale & retail | 2006 |
| Coopers Yard Hitchin Management Company Limited | Households | 2008 |
| Cootes Meadow Management Company Limited | Households | 1999 |
| Copcut Rise Management Company Limited | Households | 2020 |
| Copewell Limited | Other services | 1979 |
| Copley Estates Limited | Agriculture & fishing | 1950 |
| Coppice Construction Ltd | Construction | 2024 |
| Coppice Park (Arnold) Residents Association Limited | Households | 2002 |
| Coppolaro Properties Limited | Real estate | 2015 |
| Coppolaro Properties NO. 2 Limited | Real estate | 2023 |
| Coppolaro Properties NO. 3 Ltd | Real estate | 2024 |
| COR Consulting Ltd | Professional & scientific | 2024 |
| Coracle Online Limited | Education | 2006 |
| Coram Air Ltd | Manufacturing | 2016 |
| Corax Ltd | Professional & scientific | 2015 |
| Corbeau Solutions Ltd | Wholesale & retail | 2021 |
| Corbett Medical Limited | Administrative & support | 2018 |
| Corda Technology Co., Ltd | Other services | 2021 |
| Cordonier Segger Gehring Ltd | Professional & scientific | 2024 |
| Cordwell Consulting Limited | Education | 2008 |
| Core Residential Ltd | Real estate | 2018 |
| Core Security Consultants Ltd | Information & communication | 2006 |
| Core Sustainable Heat Management Limited | Construction | 2017 |
| Core Technical Limited | Administrative & support | 2010 |
| Core Utilities Limited | Wholesale & retail | 2025 |
| Core-Scope Endoscopy Ltd | Health & social care | 2021 |
| Corebio Limited | Professional & scientific | 2013 |
| Coregrav Ltd | Wholesale & retail | 2026 |
| Corexis Technology Limited | Wholesale & retail | 2026 |
| Corfe Place Residents Association Limited | Households | 1990 |
| Coritani Communications Limited | Professional & scientific | 2014 |
| Cornel Dinca Ltd | Construction | 2019 |
| Corner Coffe Shop Ltd | Health & social care | 2022 |
| Cornerstone College Cambridge Ltd | Education | 2022 |
| Corney Construction Ltd | Construction | 2021 |
| Cornflower Clinic Ltd | Health & social care | 2020 |
| Cornhall Developments Ltd | Administrative & support | 2008 |
| Coronation House Cambridge Management Company Limited | Real estate | 1993 |
| Corpus Conferences Limited | Hospitality | 2015 |
| Corpus Management Limited | Professional & scientific | 2019 |
| Cosa Ltd | Professional & scientific | 2023 |
| Coscione Urology Ltd | Health & social care | 2026 |
| Cosmicplanet Ltd | Wholesale & retail | 2025 |
| Cosmin Composites Ltd | Manufacturing | 2022 |
| Cosmin Duta Ltd | Manufacturing | 2026 |
| Cosminpanainte Ltd | Manufacturing | 2025 |
| Cosmo Earn Global Trading Ltd | Wholesale & retail | 2019 |
| Costa Motor Tech Ltd | Wholesale & retail | 2023 |
| Costa's Truck Ltd | Transport & logistics | 2024 |
| Costel Aviation Ltd | Manufacturing | 2025 |
| Costello Court Management Limited | Households | 1989 |