| Chrysalis Discos Limited | Arts & recreation | 2003 |
| Chu-An Group Limited | Real estate | 2022 |
| Church Fields (Lincoln) Management Company Ltd | Households | 2018 |
| Church Street Sutton Limited | Hospitality | 2023 |
| Churchill Building Developments Ltd | Construction | 2013 |
| CI Estates Limited | Real estate | 2017 |
| Ciao Willerby Limited | Hospitality | 2022 |
| Cinalp Group Ltd | Professional & scientific | 2026 |
| CINE1080 Limited | Information & communication | 2010 |
| Cinnamon Bakery Ltd | Manufacturing | 2022 |
| Circlevue Ltd | Professional & scientific | 2025 |
| Circuit Running Events Limited | Arts & recreation | 2025 |
| Cirpulitos.Motor Ltd | Wholesale & retail | 2023 |
| Cirrus Environmental Solutions Limited | Professional & scientific | 2005 |
| Citeq Ltd | Information & communication | 2014 |
| Citimetric Limited | Extraterritorial | 2013 |
| Citro Motors Ltd | Wholesale & retail | 2015 |
| City 2 Highlands Limited | Construction | 2025 |
| City Alarms & Security Ltd | Construction | 2022 |
| City Barber Hull Ltd | Other services | 2026 |
| City Builders Ltd | Construction | 2011 |
| City Centre Sign & Print Ltd | Manufacturing | 2021 |
| City Health Care Limited | Health & social care | 2016 |
| City Health Care Partnership CIC | Health & social care | 2007 |
| City Health Care Partnership Foundation | Other services | 2012 |
| City Health Dental Limited | Health & social care | 2017 |
| City Health Pharmacy Ltd | Wholesale & retail | 1989 |
| City Health Practice Limited | Health & social care | 2015 |
| City Junk Ltd | Water & waste | 2012 |
| City Living (Hull) Ltd | Real estate | 2003 |
| City M/Project Ltd | Construction | 2023 |
| City of Hull Academy Limited | Hospitality | 2012 |
| City of Hull Sport & Community Group CIC | Arts & recreation | 2010 |
| City Phones Limited | Wholesale & retail | 2018 |
| City Print Hull Ltd | Manufacturing | 2024 |
| City Spice Hull Limited | Hospitality | 2019 |
| City Tints(Hull) Ltd | Wholesale & retail | 2026 |
| City Ventures Ltd | Real estate | 2013 |
| Citygate (Yorkshire) Limited | Real estate | 1999 |
| Citymetric Limited | Extraterritorial | 2013 |
| CJ Capital Ventures Ltd | Real estate | 2024 |
| CJ Parker Properties Limited | Real estate | 2026 |
| CJ Property & Lettings Ltd | Households | 2024 |
| CJ Property Services Ltd | Real estate | 2026 |
| CJB (Hull) Limited | Construction | 2010 |
| CJC Laboratory Equipment Ltd | Manufacturing | 2024 |
| CJD Modular Ltd | Construction | 2026 |
| Cjht Properties Ltd | Real estate | 2025 |
| CJP Farms Ltd | Agriculture & fishing | 2023 |
| CJS Wind Limited | Professional & scientific | 2026 |
| CK Home (Yorkshire) Ltd | Wholesale & retail | 2024 |
| CKM Group Ltd | Professional & scientific | 1997 |
| CKR Properties Hull Ltd | Real estate | 2022 |
| CL Distribution Limited | Transport & logistics | 2025 |
| Claddingking Limited | Construction | 2015 |
| Claddplus (Nottingham) Ltd | Wholesale & retail | 2024 |
| Claddplus Distribution Ltd | Wholesale & retail | 2025 |
| Claddplus Ltd | Wholesale & retail | 2021 |
| Claim Again Ltd | Extraterritorial | 2009 |
| Claim Experts UK Ltd | Professional & scientific | 2024 |
| Claim Experts Yorkshire Ltd | Professional & scientific | 2021 |
| Claire Skow Estates Ltd | Real estate | 2023 |
| Clara-Veritas Production Ltd. | Professional & scientific | 2015 |
| Clarbel Estates Limited | Real estate | 2016 |
| Clarbel Marine Limited | Professional & scientific | 2006 |
| Claret-Scott & Co Limited | Information & communication | 2022 |
| Clarevo Ltd | Wholesale & retail | 2025 |
| Clark Accommodation Limited | Real estate | 2020 |
| Clark Care Estates Limited | Real estate | 2017 |
| Clarke&Kings Construction Ltd | Construction | 2024 |
| Clarks Jewellery Repairs Ltd | Other services | 2024 |
| Clarks Plant Hire & Contractors Ltd | Construction | 2002 |
| Clarks Watch Repairs Ltd | Other services | 2023 |
| Clarkson Business Advisory Services Ltd | Professional & scientific | 2016 |
| Clarkson Electrical Limited | Extraterritorial | 2018 |
| Clarkson Holdings Group Limited | Financial services | 2026 |
| Clarkson Property Rentals Limited | Real estate | 2021 |
| Clarkson Retail Limited | Manufacturing | 2009 |
| Clarkson Services Limited | Manufacturing | 1996 |
| Clarry Hotel Limited | Hospitality | 2017 |
| Class Living Ltd | Real estate | 2026 |
| Classaqua Limited | Wholesale & retail | 2020 |
| Classic Creations Limited | Administrative & support | 1985 |
| Claudius Galen Ltd. | Wholesale & retail | 2010 |
| Claxton Limited | Real estate | 2023 |
| CLAY10 Properties Ltd | Real estate | 2024 |
| CLC Care Limited | Health & social care | 2022 |
| CLC Wind Limited | Other services | 2020 |
| Clean and Tidy Domestic & Commercial Cleaning Ltd | Administrative & support | 2009 |
| Clean Cars (Hull) Limited | Wholesale & retail | 2013 |
| Clean Connect Ltd | Administrative & support | 2026 |
| Clean Crust Limited | Hospitality | 2024 |
| Clean Home Solutions Limited | Administrative & support | 2025 |
| Clean, Restore, Build Limited | Professional & scientific | 2014 |
| Cleaning and Paper Disposables Limited | Wholesale & retail | 1988 |
| Cleaningfacem Ltd | Real estate | 2025 |
| Cleanion Ltd | Administrative & support | 2025 |
| Cleansure Ltd | Administrative & support | 2014 |
| Clearance Hull .COM Ltd | Water & waste | 2025 |
| Clearancezone Direct Limited | Wholesale & retail | 2012 |