| Clarendon Fleet Livery Limited | Administrative & support | 2004 |
| Clark Holdings (Dunstable) Ltd | Real estate | 2026 |
| Clark PMC Ltd | Information & communication | 2021 |
| Classic Machine Shop Ltd | Manufacturing | 2024 |
| Claude & Co (Childrenswear) Ltd | Wholesale & retail | 2016 |
| Claytec Plumbing, Heating and Property Maintenance Ltd | Construction | 2024 |
| Cleanclear&Clarity Ltd | Administrative & support | 2022 |
| Clear Financial (Leicester) Ltd | Financial services | 2019 |
| Clear Financial (Midlands) Ltd | Financial services | 2017 |
| Clear Skies Coffee Ltd | Manufacturing | 2025 |
| Clear View Park Homes Ltd | Manufacturing | 2023 |
| Clear View Window Installation Limited | Construction | 2003 |
| Clearpath Children’S Services Limited | Health & social care | 2026 |
| Clearsun Property Limited | Real estate | 2024 |
| Cleartherm Glass Sealed Units Ltd | Manufacturing | 1989 |
| Cleartherm Holdings Limited | Financial services | 2023 |
| Clearview Shepshed Ltd | Administrative & support | 2026 |
| Clearwater Construction Co Ltd | Construction | 2025 |
| Cleminson & Cleminson Consulting Ltd | Professional & scientific | 2011 |
| Cliffe House Farm Ltd | Agriculture & fishing | 2023 |
| Cliffe House Mews Management Limited | Households | 1991 |
| Climate Lead Group Ltd | Professional & scientific | 2025 |
| Climatize Limited | Energy | 2020 |
| Clinical Cosmetics Limited | Health & social care | 2005 |
| Clinical UX Association CIC | Information & communication | 2023 |
| CLN Trans Ltd | Transport & logistics | 2022 |
| Cloud 9 - the Consulting Company Ltd | Professional & scientific | 2015 |
| Cloud Brothers Ltd | Wholesale & retail | 2019 |
| Cloudpeak Performance Limited | Arts & recreation | 2025 |
| Cloudsecure Ltd | Information & communication | 2019 |
| Cloudsource Ltd | Information & communication | 2010 |
| Clutter Magazine Limited | Information & communication | 2004 |
| CM Sumpter Technical Services Limited | Professional & scientific | 2012 |
| CMC Property Services Limited | Construction | 2014 |
| CMD Training Services Limited | Education | 2012 |
| CMV Vehicle Service & Repair Limited | Wholesale & retail | 2014 |
| Cmvaleting Limited | Transport & logistics | 2023 |
| CNS Capital Ltd | Construction | 2024 |
| CNW Facilities Management Limited | Administrative & support | 2024 |
| CNW Maintenance Services Limited | Administrative & support | 2024 |
| Co-Lab Group Ltd. | Real estate | 2017 |
| Coach House Court (Wood Gate) Management Company Limited | Households | 2002 |
| Coalraven Limited | Professional & scientific | 2015 |
| Coastal Kids Edit Ltd | Extraterritorial | 2024 |
| Cobden Primary School | Education | 2013 |
| Cobol Limited | Construction | 1990 |
| Cobol Property Investments Limited | Real estate | 2013 |
| Cocovits Ltd | Health & social care | 2025 |
| CODE4DRONES Ltd | Education | 2021 |
| Codefly Ltd | Information & communication | 2007 |
| Coderaven Consulting and Solutions Ltd. | Information & communication | 2017 |
| Coin Ventures Limited | Financial services | 2025 |
| Colaw Limited | Professional & scientific | 2005 |
| Cold Case Investigation Unit Ltd | Arts & recreation | 2020 |
| Cole and Co Building Contractors Ltd | Construction | 2021 |
| Cole Roberts Ltd | Wholesale & retail | 2007 |
| Coleman Lettings Limited | Real estate | 2021 |
| Coleorton Hall RTM Company Limited | Households | 2014 |
| Colin Bruton Ltd | Other services | 2015 |
| Colin Fuller Consultancy Limited | Professional & scientific | 2011 |
| Collective Health UK Ltd | Other services | 2022 |
| Collier & Collier Ltd | Construction | 2014 |
| Collier Walker Limited | Financial services | 2017 |
| Collins Chapple & Co Limited | Professional & scientific | 2004 |
| Collison Jacques Properties Limited | Real estate | 2015 |
| Colm Doherty Limited | Construction | 2014 |
| Colours Hair and Nails Limited | Other services | 2014 |
| Colton Packaging Limited | Administrative & support | 2007 |
| Combined Creations Ltd | Financial services | 2022 |
| Comfyden Ltd | Real estate | 2020 |
| Commercial Vehicle Services (Shepshed) Ltd | Wholesale & retail | 2007 |
| Community Connect Services Ltd | Administrative & support | 2026 |
| Community Enterprise Engine Ltd | Wholesale & retail | 2018 |
| Compassion & Care Limited | Health & social care | 2017 |
| Compassion Care Service Limited | Health & social care | 2016 |
| Complete Laboratory Compliance Limited | Professional & scientific | 2021 |
| Complete Wasters Limited | Water & waste | 1997 |
| Complex Visual Systems Ltd | Professional & scientific | 2015 |
| Comprehensive Prop Ltd | Construction | 2024 |
| Concentrar Ltd | Professional & scientific | 2023 |
| Concession Stores Management Ltd | Wholesale & retail | 2024 |
| Concorde Investments Ltd | Financial services | 2023 |
| Condron & Clarke Ltd | Real estate | 2021 |
| Conkerco Limited | Professional & scientific | 2014 |
| Connect With UP Limited | Information & communication | 2025 |
| Connectify Networks Ltd | Information & communication | 2024 |
| Connective AI Ltd | Administrative & support | 2025 |
| Connell Communications Limited | Other services | 2010 |
| Conscious Design Studio Ltd | Professional & scientific | 2022 |
| Consolidated Engineering and Marine Limited | Manufacturing | 1991 |
| Constantin Transport Ltd | Transport & logistics | 2021 |
| Constructer Limited | Information & communication | 2025 |
| Construction Industry Solutions Limited | Professional & scientific | 1986 |
| Consumer Code for Home Builders Limited | Other services | 2009 |
| Content Recordings Ltd | Information & communication | 2020 |
| Contour Advanced Magnetic Design Ltd | Professional & scientific | 2025 |
| Contractor Weekly Limited | Information & communication | 2010 |
| Cookie Crumble Cafe Ltd | Hospitality | 2026 |
| Cookie Crumble Dessert Limited | Hospitality | 2019 |
| Cookie Crumble Sileby Limited | Hospitality | 2021 |