| Cbforsyth Limited | Health & social care | 2016 |
| Cbfx Ltd | Financial services | 2019 |
| Cbiac Ltd | Construction | 2017 |
| Cblon Recruitment Limited | Administrative & support | 2025 |
| Cbrs Estates 1 Limited | Real estate | 2017 |
| Cbrs Estates Ltd | Construction | 2012 |
| CBU Properties Limited | Construction | 2022 |
| CC Driving Academy Ltd | Education | 2025 |
| CC Floors Limited | Construction | 2015 |
| CCA Shipping Ltd | Transport & logistics | 2022 |
| Ccaidb Limited | Administrative & support | 2025 |
| Ccbs Realisations Limited | Administrative & support | 2009 |
| CCG & CPC Limited | Hospitality | 2012 |
| Ccgh Property Limited | Real estate | 2021 |
| Ccgh Solutions Limited | Administrative & support | 2017 |
| CCK Holdings Limited | Extraterritorial | 2017 |
| CCL Cleaning Group Ltd | Administrative & support | 2007 |
| CCM (Southampton) Limited | Households | 2008 |
| CCS Facilities Limited | Professional & scientific | 2016 |
| CCS TAD Limited | Administrative & support | 2014 |
| CD & Sons Ltd | Transport & logistics | 2019 |
| CD Aerostructures Ltd | Professional & scientific | 2023 |
| CD Holly Close Limited | Hospitality | 2019 |
| Cdbg Ltd | Information & communication | 2012 |
| CDC Global Inc Ltd | Information & communication | 2025 |
| CDH Elite Ltd | Wholesale & retail | 2026 |
| CDS Property Services Ltd | Real estate | 2022 |
| CDT Construction Limited | Construction | 2013 |
| CEA Group Limited | Financial services | 2022 |
| Cearnagruadh Ltd. | Professional & scientific | 2014 |
| Cebero Limited | Agriculture & fishing | 1963 |
| Cebidae Ltd | Information & communication | 2015 |
| Cedar Action Ltd | Hospitality | 2023 |
| Cedar Court Southampton (2006) Management Company Limited | Households | 2007 |
| Cedar Park Mews Residents Association Limited | Households | 2000 |
| Cedarwood (Swanmore) Management Limited | Households | 2011 |
| Cedra Court Freehold Limited | Households | 2013 |
| Cedric Landing Ltd | Wholesale & retail | 2017 |
| Ceejaycees Ltd | Professional & scientific | 2019 |
| Ceeza Services Ltd | Transport & logistics | 2026 |
| Cego Estates Ltd | Real estate | 2025 |
| Cego Group Ltd | Financial services | 2025 |
| CEI Electrical Services Holdings Ltd | Financial services | 2025 |
| CEI Electrical Services Ltd | Construction | 2022 |
| Ceiling Light Ltd | Wholesale & retail | 2025 |
| Celcius Evans Ltd | Manufacturing | 2013 |
| Celebration of Life Cremations Ltd | Other services | 2019 |
| Celebration of Life Planning Ltd | Other services | 2020 |
| Cellcast UK Limited | Information & communication | 2001 |
| Cellular Asset Management Ltd | Information & communication | 2003 |
| Cellular Asset Management Services Limited | Information & communication | 2018 |
| Celsius Environmental Services Limited | Other services | 2000 |
| Celsius Real Estate Limited | Real estate | 2023 |
| Celt Ltd | Professional & scientific | 2024 |
| Celtic Accommodation Properties Limited | Hospitality | 2025 |
| Celuxe Ltd | Wholesale & retail | 2017 |
| CEM Plumbing & Heating Limited | Construction | 2018 |
| CEM Roofing Ltd | Construction | 2026 |
| Cendara Ltd | Wholesale & retail | 2026 |
| Ceno Holdings Limited | Financial services | 2020 |
| Censor Music Ltd | Information & communication | 2018 |
| Centenary Flooring Ltd | Other services | 2017 |
| Centenary Quay Beauty Ltd | Other services | 2025 |
| Centenary Restaurant (Soton U) Ltd | Hospitality | 2025 |
| Centenary Restaurant Ltd | Hospitality | 2020 |
| Central Cars Limited | Transport & logistics | 2024 |
| Central Haven Ltd | Households | 2025 |
| Central Point Services Limited | Construction | 2013 |
| Central Windows and Conservatories Limited | Manufacturing | 1997 |
| Centre for Climate Research and Community Empowerment Limited | Professional & scientific | 2024 |
| Centre for Driving and Traffic Research UK Ltd | Professional & scientific | 2013 |
| Centre for Transpersonal Studies Limited | Education | 2026 |
| Centre Forward I.T. Ltd | Information & communication | 1998 |
| Centrology Limited | Information & communication | 1998 |
| Century IT Services LLP | | 2007 |
| Century IT Solutions Limited | Information & communication | 2012 |
| Cepele Properties Limited | Real estate | 2023 |
| Cephalopod Services Limited | Professional & scientific | 2005 |
| Ceramic Marble & Stone Limited | Construction | 2006 |
| Ceramtec UK Ltd | Manufacturing | 1965 |
| Ceratopia Limited | Administrative & support | 2011 |
| Cerberus NDT Ltd | Professional & scientific | 2023 |
| Cereal Processing Partnership Limited | Professional & scientific | 1999 |
| Cereus Technologies Ltd | Information & communication | 2019 |
| Ceroc Portsmouth Ltd | Arts & recreation | 2023 |
| Certified Elite Performance Coaching Ltd | Education | 2021 |
| Certified Translation Direct Ltd | Professional & scientific | 2025 |
| CES Legal Limited | Professional & scientific | 2023 |
| Cesara Development Ltd | Construction | 2019 |
| Ceto Talent Ltd | Administrative & support | 2023 |
| CEW Plant Hire Ltd | Administrative & support | 2021 |
| Cezzar Ltd | Transport & logistics | 2018 |
| CF Electrical Services Ltd | Construction | 2022 |
| CF Heating Limited | Construction | 2014 |
| CFK Solent Ltd | Other services | 2025 |
| Cfrere Ltd | Real estate | 2019 |
| CFS Subco Holding Limited | Financial services | 2017 |
| CG Composites 2019 Limited | Other services | 2019 |
| CG Consultancy (UK) Limited | Information & communication | 2003 |
| CG INV Ltd | Construction | 2020 |