| Compass and Canvas Yurt Hire Ltd | Hospitality | 2024 |
| Compass Associates Limited | Administrative & support | 2009 |
| Compass Groundworks Ltd | Construction | 2015 |
| Compass Marine Services & Repairs Limited | Manufacturing | 2017 |
| Compass Point (Hilsea) Estate Management Company Limited | Households | 2008 |
| Compass Recruitment Solutions Limited | Administrative & support | 2011 |
| Compassion Care 24/7 Supported Living Services Limited | Health & social care | 2020 |
| Compassion Care Training Ltd | Other services | 2017 |
| Compassion Global Alliance Ltd | Other services | 2025 |
| Complete Developments Group Limited | Financial services | 2024 |
| Complete Digital Solutions Limited | Administrative & support | 2010 |
| Complete Facades Installations Limited | Construction | 2020 |
| Complete Facades Limited | Construction | 2010 |
| Complete Formwork Solutions Ltd | Construction | 2011 |
| Complete Kitchen & Building Solutions Ltd | Construction | 2018 |
| Complete Projects (South) Ltd | Professional & scientific | 2019 |
| Complete Property Care Group Ltd | Other services | 2024 |
| Complete UK Facilities Management Limited | Construction | 2014 |
| Complianceaid Holdings Ltd | Information & communication | 2024 |
| Composite Windows UK Ltd | Construction | 2020 |
| Composites Manufacturing Holdings Limited | Financial services | 2026 |
| Compton Associates RTM Company Limited | Households | 2022 |
| Comslink Limited | Construction | 2018 |
| Comstore Limited | Financial services | 2026 |
| Comstore Primus Ltd | Real estate | 2026 |
| Comvene Limited | Professional & scientific | 1985 |
| CON Air Heating, Ventilation & Cooling Limited | Energy | 2023 |
| Concept & Develop Ltd | Real estate | 2020 |
| Concept Collaboration Ltd | Information & communication | 2018 |
| Concept Interior Design and Decoration Limited | Construction | 2002 |
| Concept MX Ltd | Wholesale & retail | 2017 |
| Conceptos International Limited | Professional & scientific | 2019 |
| Concise (Southern) Limited | Other services | 1996 |
| Concise Packaging Ltd | Transport & logistics | 2024 |
| Concrete Equipment Finance Limited | Financial services | 2016 |
| Concrete Finance Limited | Financial services | 2019 |
| Concrete Music Limited | Information & communication | 2012 |
| Confidence Probate Limited | Professional & scientific | 2024 |
| Conlex Electrical Services Limited | Construction | 2025 |
| Connect (Egham) Limited | Construction | 2022 |
| Connect Civils Southern Ltd | Construction | 2025 |
| Connect Land (Portsmouth) Limited | Construction | 2022 |
| Connect Sales & Marketing Associates Ltd | Other services | 2012 |
| Connected MSI Ltd | Professional & scientific | 2019 |
| Connecting Enterprise Limited | Wholesale & retail | 2010 |
| Conquest Workspaces Limited | Real estate | 1976 |
| Conscia Group UK Ltd | Information & communication | 2012 |
| Conscia UK Holdco Limited | Financial services | 2024 |
| Conscious Company Ltd | Administrative & support | 2006 |
| Considered Clarity Ltd | Administrative & support | 2026 |
| Constant Fitness Ltd | Arts & recreation | 2021 |
| Construct & Pave Ltd | Construction | 2018 |
| Construct Safety and Training Limited | Professional & scientific | 2022 |
| Construct Safety Ltd | Public administration | 2020 |
| Constructfm Ltd | Construction | 2023 |
| Construction Catering (Solent) Limited | Hospitality | 2013 |
| Constructor M.B Ltd | Other services | 2018 |
| Consul Court Management Company Limited | Households | 2000 |
| Consulting Services PJB Ltd | Professional & scientific | 2023 |
| Containment Technology Limited | Manufacturing | 1995 |
| Contemporary British Painting Ltd | Construction | 2024 |
| Contimex Company Limited | Wholesale & retail | 1984 |
| Continuity Property Holdings Limited | Real estate | 2016 |
| Contract Cleaners (South) Ltd | Administrative & support | 2024 |
| Contract Climbers Ltd | Agriculture & fishing | 2019 |
| Control Building Services Ltd | Construction | 2025 |
| Control Buillding Services Ltd | Construction | 2025 |
| Control Room Solutions Ltd | Professional & scientific | 2018 |
| Convivio Ventures Ltd | Wholesale & retail | 2024 |
| Conway Mechanical Limited | Construction | 2017 |
| Coolquay Limited | Real estate | 2016 |
| Cooper and Withycombe Limited | Professional & scientific | 1999 |
| Cooper Geomatics Ltd | Administrative & support | 2014 |
| Cooper K Ltd | Hospitality | 2024 |
| Cooper Mgmt Limited | Professional & scientific | 2024 |
| Copia Concierge Ltd | Administrative & support | 2024 |
| Copnor Best Hand Car Wash Ltd | Administrative & support | 2025 |
| Copnor Cleaners Limited | Administrative & support | 2019 |
| Copnor Curry's Ltd | Hospitality | 2025 |
| Copnor Grill Ltd | Hospitality | 2024 |
| Copnor Hand Car Wash Ltd | Wholesale & retail | 2023 |
| Copnor Kitchen Limited | Hospitality | 2023 |
| Copnor Loft Conversions Ltd | Construction | 2013 |
| Copnor Market Ltd | Wholesale & retail | 2024 |
| Copnor Road Cars Limited | Wholesale & retail | 2013 |
| Copnor Road Management Company Limited | Households | 2015 |
| Copnor Takeaway Ltd | Hospitality | 2016 |
| Copper Beech Properties Ltd | Real estate | 2016 |
| Copperfields Hair Studio Limited | Other services | 2006 |
| Copthorne Court Management Company (Hove) Limited | Households | 1989 |
| COR Innovation Ltd | Professional & scientific | 2024 |
| COR Novum Ltd | Wholesale & retail | 2025 |
| Coralstone Investments Limited | Real estate | 2016 |
| Corbett Financial Solutions Limited | Financial services | 2013 |
| Cordage & Co Estate Agents Ltd | Real estate | 2026 |
| Cordage 11 Limited | Construction | 2019 |
| Cordage 13 Limited | Construction | 2020 |
| Cordage 15 Limited | Construction | 2020 |
| Cordage 2 Limited | Construction | 2016 |
| Cordage 20 Limited | Construction | 2020 |