| C S Vehicle Repairs Ltd | Wholesale & retail | 2011 |
| C Smart Distribution Limited | Transport & logistics | 2019 |
| C Spencer (Holdings) Ltd | Professional & scientific | 2010 |
| C Spencer Environmental Limited | Construction | 2005 |
| C Stainforth Services Ltd | Other services | 2025 |
| C&B Whitefriargate Ltd | Hospitality | 2022 |
| C&C Cars Repair Ltd | Wholesale & retail | 2024 |
| C&D Bars Limited | Hospitality | 2024 |
| C&D Gibbons Holdings Ltd | Real estate | 2024 |
| C&E Crystal Limited | Administrative & support | 2025 |
| C&Hp Trading Ltd | Wholesale & retail | 2025 |
| C&J Removals & Building Services Limited | Water & waste | 2025 |
| C&K Accounting Services Limited | Professional & scientific | 2020 |
| C&P Balloons Ltd | Arts & recreation | 2025 |
| C&R Electrical and Electronic Services Limited | Manufacturing | 2000 |
| C&S Property Maintenance Ltd | Construction | 2023 |
| C&S UK Group Limited | Extraterritorial | 2023 |
| C&T Flooring Ltd | Construction | 2014 |
| C&T Gyms Limited | Arts & recreation | 2022 |
| C&U Food to Go Limited | Wholesale & retail | 2020 |
| C-Store Consultancy Ltd | Other services | 2021 |
| C. a. M. Building Limited | Construction | 2011 |
| C. Bromby (Farms) Limited | Agriculture & fishing | 1960 |
| C. J'S Installations Limited | Construction | 2006 |
| C. K. Management Group Ltd | Households | 2026 |
| C. Mcdonald Brown Limited | Financial services | 1984 |
| C. Storer Rope Access Ltd | Construction | 2017 |
| C.A. Barr Limited | Professional & scientific | 2001 |
| C.B.North (Property) Limited | Real estate | 2020 |
| C.B.North (Timber) Limited | Manufacturing | 2020 |
| C.E.A.Towne(Ship Riggers)Limited | Manufacturing | 1951 |
| C.F.Struthers Limited | Manufacturing | 1932 |
| C.J Browns Bar Ltd | Hospitality | 2024 |
| C.K. (Fast Food Suppliers) Limited | Hospitality | 1999 |
| C.K. Foods (Processing) Limited | Manufacturing | 2005 |
| C.K. Foods Holdings Limited | Real estate | 2004 |
| C.K. Lettings Property Management Limited | Real estate | 2013 |
| C.K. Retail Ltd | Wholesale & retail | 2021 |
| C2D Consulting Limited | Professional & scientific | 2011 |
| C3 Group (Yorkshire) Ltd | Professional & scientific | 2022 |
| C4DI Ltd | Information & communication | 2013 |
| C4N UK Ltd | Real estate | 2025 |
| C4PS Ltd | Other services | 2024 |
| Ca-Properties Hull Ltd | Real estate | 2024 |
| Caba@Allcares Limited | Health & social care | 2015 |
| Cabcut Limited | Professional & scientific | 2017 |
| Cable Technologies (UK) Limited | Wholesale & retail | 2012 |
| Cacao Creative Ltd | Professional & scientific | 2023 |
| Cadfm Consultants Ltd | Information & communication | 2009 |
| Cafe Culture (Hull) Ltd | Hospitality | 2017 |
| Cafe M Limited | Hospitality | 2008 |
| Cafe Omelette Limited | Hospitality | 2025 |
| Cafe Sesso Ltd | Wholesale & retail | 2018 |
| Caffeinated Hull Limited | Hospitality | 2019 |
| Café Flora Ltd | Hospitality | 2025 |
| Caitlin Abra Ltd | Arts & recreation | 2025 |
| Cake World (Hull) Limited | Hospitality | 2025 |
| Cake&That Ltd | Manufacturing | 2024 |
| Cakes Incorporated Ltd | Wholesale & retail | 2021 |
| CAL Solutions Ltd | Professional & scientific | 2024 |
| Calanao Limited | Health & social care | 2018 |
| Calderton Property Development Limited | Real estate | 2001 |
| Caldus Domus Limited | Real estate | 2025 |
| Calea Drive Ltd | Transport & logistics | 2025 |
| California Classics (Hull) Limited | Wholesale & retail | 1997 |
| Calla Hull Ltd | Hospitality | 2022 |
| Callans Customs Ltd | Wholesale & retail | 2025 |
| Calma Logistic Ltd | Transport & logistics | 2022 |
| Calmar Sports Ltd | Wholesale & retail | 2024 |
| Calry Ltd | Professional & scientific | 2020 |
| Caltech Air Conditioning Ltd | Manufacturing | 2003 |
| Caltech Commercial Ltd | Other services | 2020 |
| CAM Group Limited | Financial services | 2016 |
| CAM Plumbing Limited | Construction | 2016 |
| CAM Refrigeration & Air Conditioning Limited | Construction | 2014 |
| CAM Refurbishment Limited | Construction | 2016 |
| Cambrian Solid Surface Limited | Manufacturing | 2009 |
| Cambridge Education College Ltd | Information & communication | 2024 |
| Cameleon Design & Construction Ltd | Professional & scientific | 2018 |
| Camid Limited | Construction | 2025 |
| Camodach Limited | Real estate | 2011 |
| Camp NOW Limited | Education | 2023 |
| Campbell Electrical & Renewables Ltd | Construction | 2018 |
| Campbell Electrical Services Limited | Construction | 2022 |
| Campezo Limited | Professional & scientific | 2021 |
| CAN Food Company Ltd | Hospitality | 2023 |
| CAN Invest 86 Ltd | Real estate | 2026 |
| CAN Pizza Ltd | Hospitality | 2025 |
| Candle Bright Company Limited | Wholesale & retail | 2021 |
| Candletree Properties Limited | Real estate | 2022 |
| Candy Carters Limited | Wholesale & retail | 2013 |
| Cannon Electrical Limited | Construction | 2021 |
| Canny Fast Car Solutions Ltd | Wholesale & retail | 2021 |
| Canonbourne Limited | Wholesale & retail | 1969 |
| Cantii Aestuarium Holdings Limited | Financial services | 2023 |
| Canvas and Steel Ltd | Wholesale & retail | 2026 |
| Canvas Solstice Ltd | Arts & recreation | 2025 |
| Capella Coaching & Consulting Ltd | Public administration | 2025 |
| Capital Forklift Limited | Administrative & support | 2013 |
| Caprani Media Limited | Professional & scientific | 2023 |