| Casa Solent Limited | Hospitality | 2025 |
| Casazona Enterprise Ltd | Wholesale & retail | 2024 |
| Cascades Hand Car Wash Ltd | Administrative & support | 2025 |
| Casemates Cafe Limited | Hospitality | 2024 |
| Casemates Recording Limited | Information & communication | 2024 |
| Casemates Studios Limited | Arts & recreation | 2020 |
| Cashshopper Limited | Professional & scientific | 2007 |
| Cassius Building Consultancy Ltd | Professional & scientific | 2023 |
| Castel Development Limited | Construction | 2014 |
| Castle Court (Southsea) Management Co. Limited | Households | 1991 |
| Castle Road Community Association Community Interest Company | Other services | 2024 |
| Catalystvista Ventures Ltd | Construction | 2025 |
| Cataract Surgery London Limited | Health & social care | 2023 |
| Catchpole Property Developments Limited | Construction | 2023 |
| Catering and Leisure Supplies Holdings Limited | Wholesale & retail | 2019 |
| Cathedral Close Management Co.Limited | Households | 1968 |
| Catholic Resource Centre Limited | Wholesale & retail | 1995 |
| Catral Limited | Real estate | 2011 |
| Caulfield Family Lettings Ltd | Real estate | 2025 |
| Cavalier Court Management (Portsmouth) Limited | Professional & scientific | 1982 |
| Cave Academy Ltd | Information & communication | 2017 |
| Cavenpark Ltd | Construction | 2012 |
| CB (Southern) Ltd | Construction | 2023 |
| CB Club IOW Limited | Hospitality | 2020 |
| CBF Electricians Ltd | Construction | 2023 |
| CBM Art Limited | Construction | 2022 |
| CBOWEN98 Limited | Construction | 2019 |
| Cbss Access Solutions Ltd | Construction | 2025 |
| CC Global Investments Limited | Financial services | 2025 |
| CC Squared Ltd | Real estate | 2021 |
| CC21 Limited | Administrative & support | 2025 |
| Cclc Services Ltd | Construction | 2024 |
| CCN Systems Limited | Information & communication | 2015 |
| Ccpd Trading Ltd | Wholesale & retail | 2020 |
| Ccsacv Ltd | Construction | 2023 |
| CD & PS (Fareham) Limited | Construction | 2015 |
| CD Construction (Southern) Limited | Construction | 2024 |
| CDC Lettings UK Ltd | Real estate | 2025 |
| CDC Property Rental Solutions Limited | Real estate | 2001 |
| CDL1994 2 Limited | Financial services | 2026 |
| CDL1994 3 Limited | Real estate | 2026 |
| CDL1994 Limited | Professional & scientific | 2019 |
| CDM Carpentry Limited | Construction | 2015 |
| CDM Contractors Group Ltd | Other services | 2017 |
| CDM Decorating & Interiors Ltd | Construction | 2016 |
| CDM Dents Ltd | Wholesale & retail | 2020 |
| CDM Electrical and Fire Ltd | Manufacturing | 2016 |
| CDM Property Group Ltd | Real estate | 2022 |
| CDS Locum Limited | Other services | 2020 |
| CDZ Projects Ltd | Real estate | 2022 |
| CE Interiors Ltd | Construction | 2019 |
| Cecil Road Limited | Real estate | 2017 |
| Cedar Leadership and Consultancy Limited | Health & social care | 2025 |
| Cedar Marine Limited | Professional & scientific | 2020 |
| Cedar Property (UK) Limited | Real estate | 2003 |
| Cedarwood House Limited | Health & social care | 2006 |
| Ceepharm Ltd | Wholesale & retail | 2020 |
| Celeritas Innovation Ltd | Other services | 2018 |
| Celetric Limited | Manufacturing | 2025 |
| Celia Acquisitions Ltd | Construction | 2024 |
| Celia Group Holdings Ltd | Financial services | 2024 |
| Celly's Portsmouth Ltd | Other services | 2026 |
| Celoman Ltd | Transport & logistics | 2022 |
| Celsius Heating. Plumbing Ltd | Construction | 2023 |
| Centenary Care Homes Limited | Health & social care | 2007 |
| Centra Corp Ltd | Administrative & support | 2019 |
| Centra Corporation Ltd | Extraterritorial | 2024 |
| Central Kitchens IOW Limited | Wholesale & retail | 2022 |
| Centric Assets Limited | Manufacturing | 2013 |
| Centric Print Limited | Manufacturing | 2013 |
| Centric Signs Limited | Manufacturing | 2009 |
| Centris Properties Ltd | Wholesale & retail | 2021 |
| Centro Medica UK Ltd | Health & social care | 2025 |
| Century Groundworks & Civils Ltd | Construction | 2026 |
| Cenvra Consulting Limited | Wholesale & retail | 2025 |
| Cerdan Howard Homes Ltd | Real estate | 2017 |
| Ceresmoh Ltd | Other services | 2025 |
| Cerrado Solutions Ltd | Administrative & support | 2014 |
| Certeris Limited | Real estate | 2022 |
| CF 1959 Ltd | Health & social care | 2015 |
| CG Dynamics Limited | Construction | 2018 |
| CGMG.2 Ltd | Households | 2022 |
| Cgrrl Properties Ltd | Real estate | 2025 |
| CGW Property Investment Ltd | Construction | 2019 |
| Cha-Ching Comps Limited | Arts & recreation | 2025 |
| Chacksfield RTM Company Ltd | Hospitality | 2011 |
| Chain NET Apparel CIC | Arts & recreation | 2022 |
| Chalfont Holdings Limited | Administrative & support | 2016 |
| Chalk and Cheese Catering Limited | Hospitality | 2023 |
| Chalk Door Ltd | Wholesale & retail | 2026 |
| Chalk Farm Kitchen Ltd | Hospitality | 2025 |
| Chalkridge Limited | Real estate | 2020 |
| Chalkscape Limited | Administrative & support | 2006 |
| Chalkstone Projects Ltd | Construction | 2026 |
| Challis Court Freehold Limited | Households | 2015 |
| Chalmston Limited | Real estate | 2019 |
| Champion Pallets Limited | Administrative & support | 2025 |
| Chananda Limited | Wholesale & retail | 2025 |
| Chanctonbury Care Collaborative Ltd | Health & social care | 2025 |
| Chandnishan Limited | Health & social care | 2024 |