| Confex Technology Limited | Manufacturing | 1993 |
| Confiar Consulting Limited | Professional & scientific | 2018 |
| Confidence Group Southern Ltd | Construction | 2018 |
| Configarray Ltd | Manufacturing | 2015 |
| Conical Sphere Media Limited | Information & communication | 2015 |
| Conical Sphere Music Community Interest Company | Other services | 2015 |
| Connect Group Recruitment Ltd | Administrative & support | 2020 |
| Connect Recruitment Solutions Ltd | Administrative & support | 2021 |
| Connect Storage Systems Limited | Construction | 2001 |
| Connecticate Limited | Administrative & support | 2018 |
| Connection Services Group Ltd | Wholesale & retail | 2023 |
| Connors Outsource Service Products 1 Limited | Professional & scientific | 2025 |
| Connors Outsource Service Products 2 Limited | Professional & scientific | 2025 |
| Connors Outsource Service Products 4 Limited | Professional & scientific | 2025 |
| Conor Brady Ltd | Health & social care | 2023 |
| Conrad Financial Services Ltd | Financial services | 2024 |
| Conscience Engineering Laboratories Ltd | Professional & scientific | 2022 |
| Conscious Fit Coaches Ltd | Health & social care | 2023 |
| Conscious Mind Ltd. | Health & social care | 2017 |
| Construc Training Limited | Administrative & support | 2014 |
| Construction Careers UK Ltd | Administrative & support | 2026 |
| Constructive Creativity Limited | Construction | 2023 |
| Consulo Solutions Ltd | Information & communication | 2014 |
| Consult Shannon Limited | Professional & scientific | 2004 |
| Consultancy and More Limited | Professional & scientific | 2022 |
| Consultant EYE Surgeons Partnership (Portsmouth) LLP | | 2007 |
| Consulting Online Ltd | Wholesale & retail | 2019 |
| Consulting Services (5891) Limited | Professional & scientific | 2024 |
| Consultingwerk Services UK Limited | Administrative & support | 2017 |
| Consumer Appliances Limited | Other services | 2024 |
| Consumer Brands Limited | Other services | 2023 |
| Contakt Carpets (Parkstone) Ltd. | Wholesale & retail | 1999 |
| Contem Limited | Construction | 2020 |
| Contigo Development Limited | Real estate | 2019 |
| Contract Turning Limited | Professional & scientific | 1996 |
| Contractor Expert Limited | Administrative & support | 2022 |
| Contractors Base Ltd. | Other services | 2021 |
| Contraflex Structural Solutions Limited | Professional & scientific | 2026 |
| Contrast 8 Ltd | Information & communication | 2014 |
| Contrast Accounting Limited | Professional & scientific | 2022 |
| Control Developments (UK) Limited | Professional & scientific | 2008 |
| Control Quest Limited | Professional & scientific | 2024 |
| Convergent Consulting Ltd | Professional & scientific | 2024 |
| Conversao NO Talo Limited | Wholesale & retail | 2025 |
| Converte Brasil Limited | Wholesale & retail | 2025 |
| Converte Brazil Limited | Wholesale & retail | 2025 |
| Convosphere Ltd | Information & communication | 2014 |
| Cook Constructions Design and Build Limited | Construction | 2021 |
| Cook MAG Media Ltd | Wholesale & retail | 2026 |
| Cooke Services Ltd | Construction | 2025 |
| Cookie Castle Ltd | Real estate | 2022 |
| Cookwell Developments Limited | Construction | 2016 |
| Cool 10 Limited | Construction | 2006 |
| Cool Car Limited | Wholesale & retail | 2003 |
| Coolast Ltd | Wholesale & retail | 2024 |
| Cooling Energy Services Limited | Construction | 2012 |
| Coolson Ltd | Energy | 2014 |
| Cooltech Leisure Limited | Wholesale & retail | 2009 |
| Coolway Kebab Limited | Hospitality | 2023 |
| Cooper Controls Ltd | Professional & scientific | 2026 |
| Cooper Dean Electrical Ltd | Construction | 2025 |
| Cooper& Wedlake Cuisine Ltd | Hospitality | 2018 |
| Coopertech Limited | Construction | 2024 |
| Coordico Ltd | Administrative & support | 2025 |
| Copeland Sykes Investments Ltd | Real estate | 2019 |
| Coplestone Prestige Marine Ltd | Manufacturing | 2020 |
| Copper Coatings Ltd | Extraterritorial | 2012 |
| Copper Turtle Limited | Professional & scientific | 2017 |
| Copy House Consulting Limited | Professional & scientific | 2022 |
| Copy Plus UK Limited | Manufacturing | 2006 |
| Copycare Office Equipment Limited | Administrative & support | 2004 |
| Coral Grange RTM Company Limited | Households | 2011 |
| Corbett’S Maintenance Services Ltd | Construction | 2024 |
| Corbiere Properties LLP | | 2005 |
| Corbiere Safety Solutions Ltd | Administrative & support | 2023 |
| Cordee Phones Ltd | Wholesale & retail | 2025 |
| Cordoba Rewards Ltd | Administrative & support | 2010 |
| Cordsafe Ltd | Wholesale & retail | 2015 |
| Cordula GB Ltd | Wholesale & retail | 2017 |
| Cordyfey's Tavern Café & Inn Ltd | Hospitality | 2022 |
| Core Corporate Advisers Limited | Professional & scientific | 2013 |
| Core Digital BR Ltd | Wholesale & retail | 2025 |
| Core Engineering Consulting Group Limited | Professional & scientific | 2019 |
| Core Retail Ltd | Wholesale & retail | 2024 |
| Corepathsolutions Ltd | Information & communication | 2026 |
| Coreperformanceuk Ltd | Manufacturing | 2025 |
| Corepoint Services Ltd | Information & communication | 2026 |
| Coretech IT Limited | Other services | 2025 |
| Corevo Limited | Information & communication | 2025 |
| Coreworks Property Services Limited | Construction | 2024 |
| Corfe Care Ltd | Health & social care | 2020 |
| Corfe Castle Candy LLP | | 2020 |
| Corfe Mullen Cars Ltd | Wholesale & retail | 2019 |
| Corfe Mullen Smart Repairs Ltd | Wholesale & retail | 2016 |
| Corfe Prestige Homes Limited | Construction | 2001 |
| Corfe Quality Homes Limited | Construction | 2005 |
| Corfe Solutions Limited | Information & communication | 2020 |
| Corfe View Medical Limited | Health & social care | 2021 |
| Corfe Way Limited | Real estate | 2025 |
| Corinium Real Estate Limited | Real estate | 2024 |