| Brunswick Lodge Limited | Real estate | 2016 |
| Brunswick Terrace (Hove) Limited | Households | 1989 |
| Building Better Futures Limited | Real estate | 2024 |
| Burbox Limited | Wholesale & retail | 2025 |
| Burton House RTM Company Ltd | Households | 2022 |
| BUS Stop Studios Ltd | Wholesale & retail | 2024 |
| Busy Bees Home Help Services Ltd | Administrative & support | 2021 |
| Buy Best Online Limited | Wholesale & retail | 2026 |
| BW Telecoms Design Ltd | Information & communication | 2024 |
| C Becs (Bexhill) Limited | Education | 2015 |
| C&P Group Limited | Construction | 2018 |
| C. & C. Marshall Limited | Wholesale & retail | 1971 |
| C.S. Engineering (South East) Limited | Manufacturing | 2016 |
| Caesar's 1 Palace Barbers 1 Ltd | Other services | 2025 |
| Callum Management Ltd | Professional & scientific | 2024 |
| Calon Y Teulu Limited | Health & social care | 2023 |
| Calvary Chapel Hastings Limited | Other services | 2009 |
| Calverley Mansions Management Company Limited | Real estate | 2007 |
| Campden Hill Advisers LLP | | 2009 |
| Capel-Ne-Ferne Limited | Professional & scientific | 2020 |
| Capital Accounts Limited | Professional & scientific | 2005 |
| Capital Estates Management Ltd | Construction | 2004 |
| Car Underbody Protection Ltd | Wholesale & retail | 2024 |
| Care 24/7 Healthcare Limited | Health & social care | 2015 |
| Care Direct Recruitment Ltd | Health & social care | 2013 |
| Carehome Hub Ltd | Information & communication | 2023 |
| Caring 4 ALL Ltd | Health & social care | 2011 |
| Carlton House (Tunbridge Wells) Limited | Households | 1999 |
| Carlton House Residents Brighton Limited | Households | 2011 |
| Carmel Heights Limited | Households | 2019 |
| Carten Engineering Ltd | Professional & scientific | 2009 |
| Cascade Trade Direct Ltd | Wholesale & retail | 2026 |
| Casino Productions Ltd | Information & communication | 2024 |
| Cask and Grill Ltd | Hospitality | 2023 |
| Castellanos Jordan Property Ltd | Real estate | 2024 |
| Castle Oak Care Group Ltd | Health & social care | 2026 |
| Catherine-Rose Brooks Designs Ltd | Arts & recreation | 2017 |
| Cavendish & Co Estate Agents Limited | Real estate | 2013 |
| CAW (A&B) Limited | Professional & scientific | 2015 |
| Cbsussex Consultancy Limited | Administrative & support | 2024 |
| Cbsussexwholesale Limited | Wholesale & retail | 2022 |
| Ccbuild Services Ltd | Construction | 2024 |
| Celeste Studio Limited | Professional & scientific | 2024 |
| Ceylon Cafe & Bar Ltd | Hospitality | 2024 |
| Ch/Ch LLP | | 2021 |
| Chalkley Bush Management Company Limited | Real estate | 2015 |
| Chandlers Wharf (Two) Residents Management Company Limited | Households | 2001 |
| Chandlers Wharf General Management Company Limited | Households | 2001 |
| Chanelet Ltd | Real estate | 2018 |
| Change Solutions UK Ltd | Wholesale & retail | 2004 |
| Change Workshop Limited | Information & communication | 2025 |
| Changing Chances CIC | Education | 2023 |
| Charlton-Matthews Trading Ltd | Financial services | 2021 |
| Charlwood (2025) Limited | Real estate | 2025 |
| Check Sheet Ltd | Professional & scientific | 2020 |
| Cheeky FOX LLP | | 2017 |
| Cheese and Mushrooms Limited | Arts & recreation | 2018 |
| Chelmsford Villas Limited | Households | 2003 |
| Cherry Red Pictures Ltd | Arts & recreation | 2022 |
| Cheyne Court Limited | Households | 1996 |
| Chichester Place RTM Company Limited | Extraterritorial | 2013 |
| Chicken Click Limited | Wholesale & retail | 2025 |
| Chiltern Court (Albert Road) Management Limited | Other services | 1989 |
| China Source and Supply Limited | Other services | 2009 |
| Chipotle Ltd | Professional & scientific | 2016 |
| Chisledon Property Management Ltd | Households | 2001 |
| Chowdhury Ghor Ltd | Hospitality | 2026 |
| Chrysalis Ecosystems Ltd | Information & communication | 2025 |
| Chubby Koala Ltd | Wholesale & retail | 2021 |
| Church View (London Road) Limited | Households | 2023 |
| Church Wood Construction (Southern) Limited | Construction | 2022 |
| Cipheratech Limited | Professional & scientific | 2024 |
| Circuit Properties Ltd | Real estate | 2000 |
| Circuit World Technology Ltd | Wholesale & retail | 2003 |
| Circus for Survivors CIC | Education | 2023 |
| Cireco UK Ltd | Wholesale & retail | 2025 |
| Citizens Advice 1066 | Information & communication | 1994 |
| CJ Workplace Justice UK Ltd | Information & communication | 2026 |
| CJC Kitchens Ltd | Construction | 2024 |
| Claremont Building Services Ltd | Construction | 2025 |
| Clarendon Place Ltd | Real estate | 2012 |
| Clarkson Construction (Sussex) Limited | Construction | 2025 |
| Clark’S Investment Ltd | Real estate | 2025 |
| Claro Systems Ltd | Information & communication | 2026 |
| Classicalguitarmart Limited | Extraterritorial | 2014 |
| Clean & Pack Ltd | Administrative & support | 2022 |
| Clean CUT Construction Ltd | Construction | 2019 |
| Clean CUT Property Limited | Real estate | 2026 |
| Cleaning by Faye Ltd | Administrative & support | 2023 |
| Clear OUT UK South East Ltd | Construction | 2026 |
| Clifford Court Residents Limited | Households | 1974 |
| Clifton Lettings (East Sussex) Limited | Real estate | 2022 |
| Clough PC Consultant Ltd | Professional & scientific | 2025 |
| Clued UP Training Ltd | Administrative & support | 2023 |
| Co-Worker Online Limited | Information & communication | 2019 |
| Coast Care Homes Ltd | Health & social care | 2004 |
| Coast Couriers Limited | Transport & logistics | 2003 |
| Coastal Car TEC Ltd | Extraterritorial | 2021 |
| Coastal Carpentry & Decorating Limited | Manufacturing | 2025 |
| Coco Hair C.A. Limited | Administrative & support | 2017 |