| Cleaning-Solutions 1 Limited | Administrative & support | 2023 |
| Cleaninsured Cleaning Services Limited | Administrative & support | 2025 |
| Clear Insight Limited | Information & communication | 2016 |
| Clear View Pro Cleaning Ltd | Administrative & support | 2025 |
| Clearedge AI Ltd | Information & communication | 2025 |
| Clearglass (Cambridge) Limited | Construction | 2012 |
| Clearloop Systems Limited | Information & communication | 2026 |
| Clearview Glazing & Installations Limited | Construction | 2025 |
| Cleevely & Partners Ltd | Information & communication | 2003 |
| Cleon Ltd | Wholesale & retail | 2014 |
| Cleriheli Ltd | Manufacturing | 2023 |
| Clerkin Surveyors Ltd | Professional & scientific | 2021 |
| Clerkr Ltd | Information & communication | 2025 |
| Cleverstart Corporate Services Ltd | Administrative & support | 2019 |
| CLH and Co. Ltd | Construction | 2010 |
| CLH Solar & Renewable Energy Limited | Energy | 2023 |
| Clic Languages Ltd | Professional & scientific | 2017 |
| Click Together Ltd | Administrative & support | 2023 |
| Clickn Ltd | Professional & scientific | 2024 |
| Clicknpay Limited | Wholesale & retail | 2022 |
| Clicknshare Limited | Information & communication | 2025 |
| Clickparenting Ltd | Education | 2014 |
| Clickscope Digital Ltd | Information & communication | 2019 |
| Client Drive Ltd | Professional & scientific | 2024 |
| Client Glow Ltd | Information & communication | 2026 |
| Client Motion Limited | Education | 2026 |
| Cliffco Investments Ltd | Professional & scientific | 2002 |
| Clifton Dakin Limited | Wholesale & retail | 2007 |
| Climastry Ltd | Financial services | 2022 |
| Climate Risk Metrics Ltd | Financial services | 2020 |
| Climb Foundation | Education | 2020 |
| Clindatapark Limited | Information & communication | 2019 |
| Clinical Hypnotherapy Practice Limited | Health & social care | 2017 |
| Clinical Sonography Ltd | Health & social care | 2024 |
| Clinical Technology Centre (International) Limited | Administrative & support | 1986 |
| Clinicare Hub Limited | Wholesale & retail | 2025 |
| Clinician Revision Ltd | Education | 2024 |
| Clinix Ultrasound Diagnostics Ltd | Health & social care | 2024 |
| Clink Street FX Ltd | Manufacturing | 2018 |
| CLM Composites Ltd | Manufacturing | 2024 |
| CLM Financial Ltd | Professional & scientific | 2022 |
| CLM Osteopathy Limited | Health & social care | 2013 |
| Clockwork Applications Limited | Information & communication | 2018 |
| Clockwork Motion Productions Limited | Information & communication | 2011 |
| Cloister Digital Limited | Administrative & support | 2010 |
| Cloisters (Cambridge) Lettings Limited | Real estate | 2017 |
| Cloisters Construction Limited | Construction | 2022 |
| Clopton Courtyard Cambridge LLP | | 2015 |
| Clot'Avionic Ltd | Manufacturing | 2026 |
| Cloud & Co Cambridge Limited | Other services | 2023 |
| Cloud 50 Limited | Information & communication | 2012 |
| Cloud 9 Nails & Beauty Limited | Other services | 2024 |
| Cloud Dream Innovations Limited | Wholesale & retail | 2024 |
| Cloud Storage Ltd | Extraterritorial | 2022 |
| Cloud Video Services Ltd | Financial services | 2022 |
| Cloudit Software Solutions Ltd | Information & communication | 2024 |
| Cloudless Sky Ltd | Wholesale & retail | 2021 |
| Cloudtech Innovations Ltd | Information & communication | 2023 |
| Cloughmore Homes Limited | Real estate | 2002 |
| Clouxart Ltd | Information & communication | 2020 |
| Clove Health Ltd | Health & social care | 2025 |
| Clove Properties Ltd | Real estate | 2020 |
| Clovecafe Ltd | Hospitality | 2019 |
| Clover Coaching & Consultancy Cambridge Ltd | Education | 2024 |
| Clover Hill Farm Estates Limited | Hospitality | 2025 |
| Clover Property & Investment Co. Limited | Real estate | 2014 |
| Clovermedia Limited | Information & communication | 1998 |
| Club DAN Ltd | Education | 2023 |
| Clubd Ltd | Professional & scientific | 2025 |
| Clubhouse Horning Limited | Hospitality | 2026 |
| Clupeasci Consulting Ltd | Professional & scientific | 2026 |
| CM Asset Holdings Limited | Real estate | 2020 |
| CM Cosmetics Ltd | Other services | 2024 |
| CM Lodge Ltd | Hospitality | 2025 |
| CMA Chauffeur Services Ltd | Administrative & support | 2020 |
| CMC Facilities Management Limited | Professional & scientific | 2025 |
| CMC Gloabl Market Ltd | Financial services | 2025 |
| CMC Logic Consultancy Ltd | Professional & scientific | 2025 |
| CMC Pro Delivery Ltd | Transport & logistics | 2025 |
| CMD Building Limited | Financial services | 2019 |
| CMD Intelligence Ltd | Financial services | 2026 |
| CML Medical Ltd | Professional & scientific | 2025 |
| Cmls Global Ltd | Real estate | 2025 |
| CMP Architects Limited | Professional & scientific | 2009 |
| CMR Focus and Growth Ltd | Professional & scientific | 2024 |
| CMR Surgical Limited | Manufacturing | 2014 |
| CMS (Cambridge) Limited | Administrative & support | 2011 |
| CMT Management Consultants Limited | Professional & scientific | 2007 |
| Cmtr Composites Ltd | Manufacturing | 2023 |
| CN BIO Innovations Limited | Manufacturing | 2008 |
| CN Respiratory Solutions Limited | Manufacturing | 2024 |
| CNB Composites Ltd | Manufacturing | 2018 |
| CNC Enterprises Ltd | Professional & scientific | 2024 |
| Cnctehnics Ltd | Manufacturing | 2023 |
| CNS International Ltd | Administrative & support | 2024 |
| Cns-Med Limited | Health & social care | 2026 |
| Cns-Ml Limited | Health & social care | 2019 |
| Co Tang Limited | Wholesale & retail | 2021 |
| Co-Axial Consultancy Ltd | Professional & scientific | 2023 |
| Co-Laboratories Ltd | Real estate | 2021 |