| Complete Property Surveying Ltd | Professional & scientific | 2026 |
| Complete Weed Control (Humberside) Limited | Other services | 2008 |
| Composite Doors Scunthorpe Ltd | Construction | 2022 |
| Concept Construction (Scotter) Limited | Construction | 2018 |
| Concept Websites Limited | Professional & scientific | 1999 |
| Confert Ltd | Wholesale & retail | 2026 |
| Connect Fulfilment Services Ltd | Transport & logistics | 2021 |
| Connor Shucksmith Plastering Ltd | Construction | 2021 |
| Containerking Limited | Administrative & support | 1997 |
| Contempora Ltd | Information & communication | 2020 |
| COO Estates Limited | Real estate | 2020 |
| Cooke & Co Surveyors Limited | Professional & scientific | 2014 |
| Cooper Store Ltd | Wholesale & retail | 2022 |
| Coral Air Limited | Energy | 2021 |
| Cord Door Systems Limited | Construction | 2019 |
| Corey Owen Properties Ltd | Real estate | 2025 |
| Corner PUB Limited | Hospitality | 2026 |
| Corporate Energy Procurement Limited | Professional & scientific | 2017 |
| Corporate Marketing Ltd | Professional & scientific | 2024 |
| Corrboard UK Limited | Manufacturing | 2013 |
| Corridans Limited | Wholesale & retail | 2003 |
| Cosgrove Inn Ltd | Hospitality | 2016 |
| Costica Limited | Transport & logistics | 2023 |
| Costy & SON Transport Ltd | Transport & logistics | 2023 |
| Cosy Campers 24 Limited | Construction | 2022 |
| Cottage Beck Barber Ltd | Other services | 2024 |
| Cottage Beck Corner Shop Ltd | Wholesale & retail | 2013 |
| Cottage Beck Freehold Limited | Construction | 2024 |
| Cottage Beck Stores Ltd | Wholesale & retail | 2020 |
| Cougar Developments (Glanford) Limited | Manufacturing | 1983 |
| Couldstone Services Ltd | Professional & scientific | 2020 |
| Coull Urology Limited | Health & social care | 2021 |
| County Turf Farm Ltd | Agriculture & fishing | 2020 |
| County Turf Holdings Limited | Financial services | 2020 |
| County Turf Limited | Agriculture & fishing | 1999 |
| County Turf Sports Ltd | Agriculture & fishing | 2020 |
| Couples Quest Creative Ltd | Professional & scientific | 2023 |
| Court Mates Padel Ltd | Education | 2026 |
| Courtney Simpson Collective Ltd | Other services | 2025 |
| Cover Haul Limited | Manufacturing | 2025 |
| Cover Haul Services Ltd | Manufacturing | 2025 |
| Cowan & Sanderson Properties Limited | Real estate | 2025 |
| Coxagen Limited | Health & social care | 2022 |
| Coys Welding Ltd | Manufacturing | 2022 |
| Cozee Ltd | Wholesale & retail | 2011 |
| CP Automation Limited | Manufacturing | 2005 |
| Cpluse Ltd | Wholesale & retail | 2019 |
| CPS Medical Imaging Ltd | Health & social care | 2020 |
| CR Fenwick Holdings Limited | Financial services | 2026 |
| CR Property Lets Ltd | Real estate | 2021 |
| CR7 Trading Ltd | Wholesale & retail | 2024 |
| Crabtree Commercial Developments Limited | Real estate | 2004 |
| Craft a Camper Ltd | Wholesale & retail | 2021 |
| Craig Hunt Ltd | Administrative & support | 2018 |
| Craigleon Property Management Ltd | Construction | 2026 |
| Craigs Driver Hire Ltd | Transport & logistics | 2025 |
| Cram Vape Gainsborough Ltd | Wholesale & retail | 2021 |
| Cram Vape Ltd | Wholesale & retail | 2010 |
| CRAVE1997 Limited | Hospitality | 2026 |
| Crawfords Electronics Limited | Wholesale & retail | 2002 |
| Crawfords Shooting Supplies Limited | Manufacturing | 2003 |
| CRE8IVE Layers Limited | Manufacturing | 2025 |
| Creative Carbon UK Ltd | Wholesale & retail | 2024 |
| Creative Health Solutions Ltd | Professional & scientific | 2024 |
| Creatorbloc Ltd | Information & communication | 2022 |
| Credland Electrical Limited | Construction | 2013 |
| Crepe Joy Ltd | Hospitality | 2025 |
| Crescent Villa (Filey) Management Company Limited | Households | 2020 |
| Crewdogg Ltd | Administrative & support | 2026 |
| Crewsade Ltd | Arts & recreation | 2026 |
| CRG Commercial Property Ltd | Real estate | 2024 |
| Cristian Transport Logistic Ltd | Transport & logistics | 2026 |
| CRISTRANS1 Ltd | Transport & logistics | 2023 |
| Criticalfailco Ltd | Wholesale & retail | 2025 |
| Crofthous Development Ltd | Construction | 2024 |
| Crosby Brokerage Ltd. | Other services | 2010 |
| Crosby Plant and Tool Hire Limited | Administrative & support | 2023 |
| Cross Padel Limited | Arts & recreation | 2025 |
| Cross-Guard DCS Limited | Manufacturing | 2025 |
| Crossdressme Limited | Wholesale & retail | 2023 |
| Crowle and Ealand Regeneration Project Limited | Wholesale & retail | 1998 |
| Crowle Country Homes Limited | Construction | 1987 |
| Crowle Spice Ltd | Hospitality | 2023 |
| Crown Hospitality Leisure Ltd | Hospitality | 2020 |
| Crown Media Solutions Ltd | Professional & scientific | 2018 |
| Cryne Limited | Wholesale & retail | 2006 |
| Cryo Body Ltd | Health & social care | 2016 |
| Crystal Car Wash DN16 Ltd | Wholesale & retail | 2024 |
| Crystal Clear Cleaning (Lincs) Limited | Administrative & support | 2019 |
| Crystal Media UK Ltd | Information & communication | 2019 |
| Crystal Tree & Gardening Service Ltd | Administrative & support | 2023 |
| CS Close Protection Ltd | Administrative & support | 2023 |
| Cscm Solutions Ltd | Administrative & support | 2019 |
| CSH Autos Ltd | Wholesale & retail | 2025 |
| CSP Technology Ltd | Manufacturing | 2001 |
| Cssl Ltd | Information & communication | 2000 |
| Cstaylor Investments Limited | Financial services | 2025 |
| Ctderm Consulting Limited | Health & social care | 2019 |
| CTP Trading Limited | Professional & scientific | 1999 |
| CTS Pubs & Bars Ltd | Hospitality | 2026 |