| Clever Media Ltd | Wholesale & retail | 2019 |
| CLG Bexleyheath Ltd | Other services | 2023 |
| CLG Harrow Ltd | Construction | 2022 |
| Climastar UK Ltd | Extraterritorial | 2025 |
| Clinical Centre Limited | Health & social care | 2019 |
| Clique Clothing Ltd | Wholesale & retail | 2014 |
| Clive Austerberry Limited | Real estate | 1990 |
| Clivia International Business Limited | Professional & scientific | 2011 |
| CLN Superstore Ltd | Wholesale & retail | 2026 |
| Clockwork Social Ltd | Information & communication | 2018 |
| Cloud Tunnel Ltd | Information & communication | 2025 |
| Cloudvance Marketing UK Ltd | Information & communication | 2018 |
| Clove&Co Ltd | Other services | 2020 |
| Clowes & Co. LLP | | 2017 |
| Club Vibora Ltd | Arts & recreation | 2026 |
| Clubhouse Collective Limited | Arts & recreation | 2014 |
| Clucknbun Limited | Hospitality | 2025 |
| Clypt Studio Limited | Information & communication | 2026 |
| Clyq Ltd | Professional & scientific | 2015 |
| CM Business Services (Staffordshire) Limited | Professional & scientific | 2017 |
| CM Designs Ltd | Construction | 2024 |
| Cm-Tec Ltd | Health & social care | 2022 |
| Cmbargains Ltd | Wholesale & retail | 2023 |
| CMC Sourcing Limited | Real estate | 2025 |
| CMF Tax Ltd | Professional & scientific | 2025 |
| CMG Cleantech Limited | Professional & scientific | 2025 |
| CMG Retail Ltd | Wholesale & retail | 2022 |
| CMH Driver Services Limited | Transport & logistics | 2020 |
| CMP Delivery Ltd | Transport & logistics | 2022 |
| CMP Mini Buses Limited | Transport & logistics | 2011 |
| CMP Recruitment Limited | Construction | 2021 |
| CMV Assessors Ltd | Real estate | 2025 |
| Cmvmh Ltd | Education | 2022 |
| CMW Surveyors Limited | Professional & scientific | 2015 |
| Co Ductwork Ltd | Construction | 2025 |
| Co Technology Limited | Information & communication | 2024 |
| Coates-Smith Racing GP Limited | Arts & recreation | 2024 |
| Coates-Smith Racing LP | | 2024 |
| Cobb Lloyd Refractories Limited | Construction | 2010 |
| Cobden Street 1969 Limited | Extraterritorial | 2015 |
| Cobra Evolution Martial Arts Academy Ltd | Arts & recreation | 2025 |
| Cobra KOI Elite Ltd | Wholesale & retail | 2025 |
| Cobridge Car Testing Centre Limited | Wholesale & retail | 2017 |
| Cobridge Hand Carwash Limited | Administrative & support | 2025 |
| Coco Luxe Beauty Group Ltd | Other services | 2024 |
| Coco Nail and Beauty Limited | Other services | 2024 |
| Code DEV Ltd | Information & communication | 2023 |
| Code Dynamics Ltd | Information & communication | 2018 |
| Code Mamba Ltd | Information & communication | 2025 |
| CODEIT9 Ltd | Wholesale & retail | 2025 |
| CODRU85 Ltd | Transport & logistics | 2019 |
| Coetus Associates Ltd | Information & communication | 2018 |
| Coffee Craving UK Limited | Hospitality | 2018 |
| Cogent Capital Investments Ltd | Financial services | 2025 |
| Coherence Within Ltd | Health & social care | 1999 |
| Coitec IT Trade Ltd | Wholesale & retail | 2022 |
| Colborne (HGG) 2012 Limited | Wholesale & retail | 2012 |
| Colbornes Trade Parts Limited | Wholesale & retail | 2006 |
| Colcough Refractory Services Limited | Construction | 2025 |
| Coldcell Hire Ltd | Construction | 2026 |
| Cole & Camm Estates Ltd | Real estate | 2026 |
| Colebrook & Burgess Holdings Limited | Administrative & support | 2002 |
| Colebrook & Burgess Limited | Wholesale & retail | 1997 |
| Coleman Employment Law Limited | Professional & scientific | 2016 |
| Coles Therapy Limited | Health & social care | 2017 |
| Colin Lancaster Commercials Limited | Wholesale & retail | 2018 |
| Collabherate Limited | Professional & scientific | 2024 |
| COLLABOR8ING Limited | Wholesale & retail | 2026 |
| Collective Holdings Ltd | Real estate | 2022 |
| College Grill Shelton Limited | Hospitality | 2023 |
| College of Mediators | Other services | 1996 |
| Collins Authentic Ltd | Health & social care | 2019 |
| Collins Performance Engineering Limited | Manufacturing | 2000 |
| Collins Research & Development Limited | Professional & scientific | 2004 |
| Colmowltd Ltd | Professional & scientific | 2026 |
| Colonel Properties Limited | Real estate | 2025 |
| Colorama Pharmaceuticals Limited | Transport & logistics | 1982 |
| Colorful Sky Trade Ltd | Wholesale & retail | 2024 |
| Colour Media Productions Limited | Information & communication | 2019 |
| Coloured Sheep Limited | Education | 2019 |
| Colourful Improvements Ltd | Construction | 2019 |
| Coltslow Farm Road Management Co Ltd | Households | 2023 |
| Colubase Minton Ltd | Construction | 2020 |
| Comar Trans Ltd | Administrative & support | 2020 |
| Combined Services (SOT) Limited | Construction | 2008 |
| Combustion Linings Limited | Wholesale & retail | 1997 |
| Comeca UK Limited | Manufacturing | 2014 |
| Coment Group Ltd | Other services | 2017 |
| Comfort Air Travels Ltd | Administrative & support | 2025 |
| Comfort Travels Taxi Ltd | Transport & logistics | 2022 |
| Comfy House Limited | Wholesale & retail | 2015 |
| Comley Properties Ltd | Real estate | 2026 |
| Commark Limited | Manufacturing | 2005 |
| Commence CIC | Education | 2023 |
| Commercial and Car Fleet Services Limited | Wholesale & retail | 2022 |
| Commercial and Car Limited | Wholesale & retail | 2011 |
| Commercial Energy Ltd | Wholesale & retail | 2016 |
| Common Thread Impact Consulting Limited | Administrative & support | 2025 |
| Common Thread Impact Ventures Limited | Financial services | 2025 |
| Commtech FM Limited | Construction | 2018 |