| CBS Building Services Limited | Construction | 1992 |
| Cecaelius Ltd | Professional & scientific | 2024 |
| Chakana Consulting Limited | Information & communication | 2026 |
| Challis Construction Limited | Construction | 2021 |
| Chandraful Limited | Hospitality | 2026 |
| Channel Court (Lancing) Management Co. Ltd | Households | 2000 |
| Charlwards Bathrooms Limited | Construction | 2016 |
| Chartwell Salon Supply Limited | Manufacturing | 1948 |
| Chatak Ltd | Hospitality | 2024 |
| Chatsworth Engineering Services Limited | Manufacturing | 1996 |
| Cheal (Worthing) Limited | Wholesale & retail | 1985 |
| Cheema Dairy Limited | Hospitality | 2023 |
| Chef Huxford-Weilding Ltd | Hospitality | 2024 |
| Chelwood Farm Ltd | Arts & recreation | 2007 |
| Cheshire House Developments Limited | Real estate | 1993 |
| Chivalry Hall Ltd | Households | 2021 |
| Chris C Edwards Limited | Construction | 2015 |
| Chris Payne Music Ltd | Arts & recreation | 2003 |
| Chrischeeseman Ltd | Professional & scientific | 2024 |
| Chuckaburger Brighton Ltd | Hospitality | 2025 |
| Chuckaburger Ltd | Hospitality | 2022 |
| Cindat (UK) Limited | Real estate | 2024 |
| Cine Image Processing Ltd | Professional & scientific | 2025 |
| Cire Limited | Other services | 2003 |
| Citadel Property Holdings Ltd | Real estate | 2024 |
| City Dampcoursing (Surveying) Limited | Construction | 1994 |
| CJH Solutions Ltd | Wholesale & retail | 2016 |
| Cjjq Design Ltd | Professional & scientific | 2024 |
| Claire Michelle Pilates Ltd | Other services | 2015 |
| Clapgate Limited | Real estate | 1983 |
| Clare's Pet Care Ltd | Administrative & support | 2019 |
| Clarity Accounting Limited | Professional & scientific | 2005 |
| Clarity Probate Limited | Extraterritorial | 2005 |
| Clarke Developments (Shoreham) Ltd | Real estate | 2020 |
| Clarke Developments Group Ltd | Financial services | 2022 |
| Clayton Cleaning Consultants Limited | Administrative & support | 2000 |
| Cleanall Service Limited | Administrative & support | 2009 |
| Cleaning Equipment Services Limited | Administrative & support | 2003 |
| Cleaning Solutions Sussex Limited | Administrative & support | 2014 |
| Clearpath UK Consultancy Limited | Administrative & support | 2017 |
| Clearskin Aesthetics Limited | Health & social care | 2018 |
| Click Through Limited | Professional & scientific | 2019 |
| Closr App Ltd | Information & communication | 2024 |
| CM Advisory American Ltd | Financial services | 2021 |
| CM Advisory American Partners Ltd | Financial services | 2021 |
| CM Advisory Cement Partners Ltd | Financial services | 2022 |
| CM Advisory Investments Ltd | Financial services | 2021 |
| CM Advisory Ltd | Professional & scientific | 2019 |
| CM Apparel Ltd | Manufacturing | 2023 |
| CMF Electrical Ltd | Construction | 2023 |
| CMR Building and Design Limited | Construction | 2024 |
| CNM Plumbing Solutions Limited | Construction | 2024 |
| Coaching and Mentoring for Success Limited | Professional & scientific | 2025 |
| Coast Construction Limited | Construction | 2022 |
| Coast to Country Fencing and Landscaping Ltd | Administrative & support | 2023 |
| Coastal Trades Collective Ltd | Manufacturing | 2021 |
| Coastal Van Hire Ltd. | Administrative & support | 2025 |
| Cocktail Chemistry Ltd | Hospitality | 2019 |
| Coffee Doctor Sussex Limited | Manufacturing | 2019 |
| Cole Electrical Limited | Construction | 2015 |
| Coleman & SON Limited | Transport & logistics | 2003 |
| Collab Music Services Ltd | Administrative & support | 2019 |
| Colofs.Co.Uk Ltd | Administrative & support | 2022 |
| Colombo Travel Ltd | Administrative & support | 2023 |
| Colour Craft Direct Ltd | Wholesale & retail | 2010 |
| Columna Ltd | Financial services | 2024 |
| Commando Investments Ltd | Construction | 2018 |
| Commonsense and Airmanship Always Apply Ltd | Transport & logistics | 2017 |
| Communicating Business Ltd. | Professional & scientific | 2013 |
| Community Appeal Media Limited | Manufacturing | 2004 |
| Compass Growth Limited | Professional & scientific | 2025 |
| Complete Clean Sussex Ltd | Administrative & support | 2026 |
| Complete Telecoms Limited | Information & communication | 2004 |
| Computerised Quantity Surveying Services Limited | Professional & scientific | 2001 |
| Concept Creative Consultants Limited | Arts & recreation | 2000 |
| Connect Media Group Limited | Professional & scientific | 2021 |
| Consider IT Cleared Ltd | Information & communication | 2019 |
| Consumer Consulting Co Ltd | Professional & scientific | 2018 |
| Controls Consulting Limited | Information & communication | 2017 |
| Conveyconnect Ltd | Real estate | 2025 |
| COORDINAT3D Ltd | Wholesale & retail | 2015 |
| Cordeb Limited | Professional & scientific | 2024 |
| Core Shift One Ltd | Households | 2025 |
| Cornerstone Investment Group Ltd | Financial services | 2022 |
| Corporate Financial Trading Limited | Financial services | 2008 |
| Corporate Litigation Funding Limited | Financial services | 2008 |
| Cortex Fusion Engineering Ltd | Information & communication | 2025 |
| Corvus Associates Ltd | Professional & scientific | 2020 |
| Crabtree Inn Limited | Wholesale & retail | 2015 |
| Crabtree Lane Garage Ltd | Wholesale & retail | 2012 |
| Craftwork Carpets Limited | Wholesale & retail | 2007 |
| Craftwork Flooring Limited | Extraterritorial | 2009 |
| Craven Court (Lancing) Limited | Households | 2014 |
| Creasey Investment Group Ltd | Real estate | 2023 |
| Creed Management Solutions Limited | Professional & scientific | 2001 |
| Crest Labs Ltd | Information & communication | 2024 |
| Crockerz Events Ltd | Professional & scientific | 2019 |
| Cross Navigation Limited | Transport & logistics | 2021 |
| Crown Building Management Limited | Extraterritorial | 2016 |
| Cryptex Capital Limited | Financial services | 2026 |