| Coachcorner Ltd | Arts & recreation | 2023 |
| Coast 2 Coast Logistics Ltd | Transport & logistics | 2012 |
| Cobbletons Ltd | Information & communication | 2018 |
| Cobe Romford Ltd | Hospitality | 2025 |
| Coborn Properties Limited | Real estate | 1996 |
| Cobra Solutions Ltd | Administrative & support | 2022 |
| Coco Estates Limited | Real estate | 2016 |
| Cocoa's Salon Ltd | Other services | 2019 |
| Cocoapparelsnowdonia Ltd | Other services | 2023 |
| Code Blue Education Ltd | Health & social care | 2011 |
| Code Chemistry Limited | Administrative & support | 2024 |
| Code Tribe Kids Limited | Information & communication | 2024 |
| Codeara Ltd | Information & communication | 2026 |
| Codebreakers Studio Limited | Information & communication | 2026 |
| Codemynt Ltd | Information & communication | 2025 |
| Codeperf Ltd | Information & communication | 2015 |
| Codexco Ltd | Wholesale & retail | 2023 |
| Coease Limited | Other services | 2023 |
| Coffee & BUN Ltd | Hospitality | 2024 |
| Coffee Neighbours Ltd | Hospitality | 2021 |
| Cogence Limited | Professional & scientific | 2016 |
| Cognition Foundry Ltd | Information & communication | 2010 |
| Cognition Health Ltd | Professional & scientific | 2021 |
| Cognytix Limited | Education | 2023 |
| Coido Family Distillers Ltd | Manufacturing | 2024 |
| Coin Office Ltd | Financial services | 2025 |
| Colas Partners and Solutions Ltd | Construction | 2024 |
| Colbee Limited | Professional & scientific | 2020 |
| Coldon Engineering Co.Limited | Professional & scientific | 1967 |
| Colenso Printing Company Limited | Real estate | 1965 |
| Coletherm Limited | Construction | 2020 |
| Coley Street Consulting Ltd | Professional & scientific | 2023 |
| Colin Engineers Ltd | Manufacturing | 2014 |
| Coll Consulting Limited | Construction | 2016 |
| COLLABR8 Club Limited | Other services | 2025 |
| Collection DM Ltd | Construction | 2023 |
| Collective 93 Ltd | Other services | 2026 |
| Collective Demolition Limited | Construction | 2023 |
| College Driving School Ltd | Extraterritorial | 2025 |
| College of Management Technology Limited | Public administration | 2025 |
| Collett Solutions Ltd | Construction | 2024 |
| Collier ROW Catholic Club Limited | Hospitality | 2002 |
| Collier WOK Limited | Hospitality | 2026 |
| Collinzo Ltd | Health & social care | 2025 |
| Colman Construction Consultancy Services Ltd | Construction | 2024 |
| Colman Management Services (CMS) Limited | Construction | 2012 |
| Colombo Builders Ltd | Construction | 2021 |
| Colonel's Properties & Developments Limited | Construction | 2021 |
| Colonel's Properties & Investments Limited | Real estate | 2018 |
| Colonel's Properties Ltd | Real estate | 2016 |
| Colour 4 Colour Ltd | Wholesale & retail | 2025 |
| Colourful Healthcare CIC | Health & social care | 2018 |
| COM Safer Care Ltd | Health & social care | 2020 |
| Combined Cameras Ltd | Information & communication | 2015 |
| Come & Drive Limited | Other services | 2014 |
| Comendrive Limited | Education | 2021 |
| Comfort ARK Haven Ltd | Health & social care | 2026 |
| Comfort Lounge Ltd | Manufacturing | 2025 |
| Comitas Care Limited | Health & social care | 2023 |
| Commerce Essentials Limited | Information & communication | 2021 |
| Commerce FDN Ltd | Wholesale & retail | 2023 |
| Commercial EPC Ltd | Other services | 2019 |
| Commercial Road Chambers Investments Ltd | Real estate | 2024 |
| Commissioned Ltd | Arts & recreation | 2012 |
| Commitment Care Limited | Administrative & support | 2017 |
| Common Sense Construction Ltd | Construction | 2018 |
| Common Sense Trading UK Ltd | Wholesale & retail | 2022 |
| Common Stations Ltd | Education | 2014 |
| Commonwealth Estates Limited | Real estate | 2016 |
| Comms Consultancy Solutions Ltd | Administrative & support | 2012 |
| Comms Transport Services Ltd | Transport & logistics | 2023 |
| Commsparc Ltd | Construction | 2018 |
| Company Affairs International Ltd | Professional & scientific | 2025 |
| Company Cardozo Ltd | Wholesale & retail | 2025 |
| Compassionate Care Partners Ltd | Transport & logistics | 2025 |
| Compassionate Pear-Trees Ltd | Health & social care | 2022 |
| Compbass Ltd | Professional & scientific | 2013 |
| Complete BS Limited | Administrative & support | 2020 |
| Complete Cleaning Services (UK) Ltd | Administrative & support | 2003 |
| Complete Collective Limited | Education | 2025 |
| Complete Financing Solutions Ltd | Administrative & support | 2012 |
| Complete Football Academy Limited | Education | 2022 |
| Complete in Sports Limited | Education | 2026 |
| Complete Maintenance Essex Ltd | Construction | 2022 |
| Complete Shading Solutions Ltd | Other services | 2024 |
| Complete Ultrasound Services Limited | Professional & scientific | 2010 |
| Compliance Software Corp Ltd | Information & communication | 2025 |
| Complianceflow UK Ltd | Wholesale & retail | 2026 |
| Compliant Care Solutions Ltd | Professional & scientific | 2023 |
| Compris Beauty Ltd | Wholesale & retail | 2019 |
| Computers 4 U Limited | Information & communication | 2022 |
| Comunit Advertising Limited | Professional & scientific | 2021 |
| Comunit Investments Ltd | Real estate | 2020 |
| Comunit Limited | Information & communication | 2019 |
| Conbur Ltd | Real estate | 2021 |
| CONCATEN8 Professional Services Limited | Administrative & support | 2023 |
| Concept Advisory Limited | Administrative & support | 2017 |
| Concept Solar Systems Ltd | Construction | 2011 |
| Concept Windows Limited | Extraterritorial | 2012 |
| Conceptar Ltd | Information & communication | 2023 |