| Claude Hellowell Limited | Transport & logistics | 1955 |
| Clay Pipe Development Association Limited | Other services | 1965 |
| Clayton Dental Practice Limited | Health & social care | 2011 |
| Clean at Last Domestic Limited | Administrative & support | 2018 |
| Clean at Last Limited | Administrative & support | 2016 |
| Cleaning Solutions North Limited | Administrative & support | 2017 |
| Cleanmet Limited | Water & waste | 1964 |
| Clear Air Technology Limited | Manufacturing | 2020 |
| Clear IT Consultancy Ltd | Information & communication | 2023 |
| Clear My Credit Ltd | Financial services | 2018 |
| Clear Site Limited | Professional & scientific | 2025 |
| Clear Skyline Windows Ltd | Manufacturing | 2024 |
| Clearalign Ltd | Health & social care | 2022 |
| Clearchoice Recycling Limited | Transport & logistics | 2023 |
| Clearsight UAV Ltd | Professional & scientific | 2025 |
| Clearstone Holdings Limited | Professional & scientific | 2013 |
| Clearwater (NW) Limited | Real estate | 2003 |
| Cleasby Health Ltd | Health & social care | 2019 |
| Clever Booking Solutions Limited | Hospitality | 2025 |
| Click Furniture Ltd | Wholesale & retail | 2016 |
| Clickcartmarketing Ltd | Wholesale & retail | 2025 |
| Client Safe Holdings Limited | Professional & scientific | 2025 |
| Cliffe Builders Ltd | Construction | 2013 |
| Clifton Computers Limited | Information & communication | 1989 |
| Climax Joinery Contracts Limited | Construction | 2005 |
| Clinic Prescribing Support Ltd | Health & social care | 2023 |
| Clinic Prive Limited | Health & social care | 2015 |
| Clinical Education Consultancy Ltd | Health & social care | 2014 |
| Clinserv Limited | Real estate | 2022 |
| CLK Design Northern Limited | Wholesale & retail | 2021 |
| CLK Ryburn Limited | Professional & scientific | 2017 |
| CLK Yorkshire Limited | Wholesale & retail | 2017 |
| CLM Flooring Limited | Construction | 2021 |
| Clockface 2025 Limited | Real estate | 2025 |
| Close Property Developments Ltd | Construction | 2022 |
| CLOTHING2U Limited | Wholesale & retail | 2024 |
| Cloud 9 Complex Limited | Arts & recreation | 2023 |
| Cloud Express Limited | Administrative & support | 2025 |
| Cloud KNG Ltd | Wholesale & retail | 2024 |
| Cloud Tasty Limited | Wholesale & retail | 2025 |
| Cloudkeepers Ltd | Professional & scientific | 2022 |
| Clough House Liveries Ltd | Agriculture & fishing | 2026 |
| Clough Lane Childcare Ltd | Health & social care | 2020 |
| Clover International Group Ltd | Administrative & support | 2021 |
| Clowns Without Borders UK | Health & social care | 2024 |
| Clsjls Limited | Real estate | 2026 |
| CLT Joinery Services Limited | Construction | 2025 |
| Cluaranach Limited | Wholesale & retail | 2012 |
| Clubhardware Ltd | Information & communication | 2004 |
| CM Claims Limited | Professional & scientific | 2011 |
| CM Holdings Group Limited | Financial services | 2022 |
| CM Tuned Ltd | Wholesale & retail | 2021 |
| CNB China China Noodles Bar Limited | Hospitality | 2023 |
| CNC Apps Ltd | Professional & scientific | 2025 |
| CNC Extract Ltd | Professional & scientific | 2021 |
| CNC Precision Ltd | Construction | 2021 |
| Co View Holdings Limited | Professional & scientific | 2018 |
| Co View Limited | Information & communication | 1995 |
| Coaching Leader Pathway Ltd | Professional & scientific | 2026 |
| Coast 2 Coast ( Halifax) Ltd | Transport & logistics | 2023 |
| Coast 2 Coast Cars Limited | Wholesale & retail | 2001 |
| Cobco 914 Limited | Professional & scientific | 2010 |
| Cobra Contact Limited | Professional & scientific | 2021 |
| Cockaigne Ltd | Professional & scientific | 2020 |
| Cocktail Club Halifax Limited | Wholesale & retail | 2024 |
| Cocoa Mayfair Limited | Wholesale & retail | 2020 |
| Code 82 Limited | Information & communication | 2011 |
| Code Solution Studios Ltd | Information & communication | 2019 |
| COE Property Investments Ltd | Real estate | 2023 |
| Coffeemob Ltd | Hospitality | 2025 |
| Coleridge Consulting Associates Ltd | Professional & scientific | 2024 |
| Coley Equine & Cattle Ltd | Agriculture & fishing | 2024 |
| Colin Crawshaw Limited | Construction | 2003 |
| Colin's Tyre Services Limited | Wholesale & retail | 2003 |
| Collaku Properties Limited | Professional & scientific | 2023 |
| Collett & Sons Limited | Transport & logistics | 2016 |
| Collett Acquisitions Limited | Financial services | 2025 |
| Collett Heavy Lift Limited | Transport & logistics | 2016 |
| Collett Holdings Limited | Financial services | 2016 |
| Collett Marine Limited | Transport & logistics | 2016 |
| Collett Special Transport Limited | Transport & logistics | 2016 |
| Collett Transport Consulting Limited | Transport & logistics | 2016 |
| Collins Care Services Ltd | Health & social care | 2022 |
| Colour Ribbons Limited | Wholesale & retail | 1984 |
| Colourco Limited | Manufacturing | 2002 |
| Colville Electrical Services Limited | Construction | 2019 |
| Combined Brewery Services Limited | Manufacturing | 1992 |
| Combined Minds Ltd | Professional & scientific | 2019 |
| Combinedesign Limited | Information & communication | 2006 |
| Comficasa Ltd | Wholesale & retail | 2025 |
| Commerce Zone Ltd | Wholesale & retail | 2020 |
| Commercial Kitchen Projects Ltd | Wholesale & retail | 1985 |
| Community Foundation for Calderdale | Health & social care | 1991 |
| Community Support Holdings Limited | Financial services | 2022 |
| Community Transport Calderdale Ltd | Transport & logistics | 2002 |
| Community Works (Mixenden) | Education | 2016 |
| Compass HV Services Limited | Professional & scientific | 2013 |
| Compass Transport Solutions Ltd | Professional & scientific | 2023 |
| Complete Assist Limited | Other services | 2015 |
| Complete Brickwork Ltd | Construction | 2010 |