| Complete Brickwork Properties Ltd | Real estate | 2020 |
| Complete Catering Equipment Ltd | Wholesale & retail | 2018 |
| Complete Computers Leeds Ltd | Information & communication | 2021 |
| Complete Construction Services (CCS) Ltd | Construction | 2024 |
| Complete Garden Landscapes UK Ltd | Administrative & support | 2025 |
| Complete M&E Services (Cmes) Ltd | Construction | 2021 |
| Complete Packaging Services Limited | Manufacturing | 1993 |
| Complete Process Ltd | Real estate | 2025 |
| Complete RS Holding Group Ltd | Real estate | 2024 |
| Complete Scaffolding North Limited | Construction | 2017 |
| Computech Solutions Ltd | Information & communication | 2025 |
| Computrading Limited | Wholesale & retail | 2010 |
| Concam Vehicle Movement Ltd | Transport & logistics | 2024 |
| Conclude Limited | Construction | 2009 |
| Concrete Consultancy Limited | Information & communication | 2020 |
| Confidence Circuit Limited | Education | 2026 |
| Confined Space Services (UK) Ltd | Mining & quarrying | 2011 |
| Conk Construction Services Ltd | Construction | 2025 |
| Conks Caravan Hire Ltd | Hospitality | 2025 |
| Connah Judson Financial Planning Limited | Professional & scientific | 2024 |
| Connaught PSV Ltd | Wholesale & retail | 2011 |
| Connect AI Solutions Ltd | Information & communication | 2024 |
| Connect Global Solutions Ltd | Professional & scientific | 2023 |
| Conquest Flooring Limited | Construction | 2012 |
| Consortio (UK) Limited | Real estate | 2005 |
| Consult & SEE Limited | Information & communication | 2011 |
| Consult 21 Ltd | Information & communication | 2015 |
| Consultasaurus Ltd | Professional & scientific | 2021 |
| Consulting SAJ Ltd | Professional & scientific | 2019 |
| Contact Fabrications Limited | Manufacturing | 1993 |
| Contexted Ltd | Other services | 2018 |
| Continental Halifax Ltd | Wholesale & retail | 2026 |
| Continentel Ltd | Information & communication | 2010 |
| Continuum Healthcare Frontline Technologies Ltd | Information & communication | 2026 |
| Contract Laser Cutting Ltd | Professional & scientific | 2014 |
| Contracut Limited | Manufacturing | 2012 |
| Control & Electrical Solutions Ltd | Construction | 2002 |
| Control and Instrumentation Services Ltd | Professional & scientific | 2023 |
| Controlled Temperature Solutions Ltd | Manufacturing | 2006 |
| Converga Digital Limited | Information & communication | 2021 |
| Converga Ltd | Information & communication | 2009 |
| Conveyor Technology Limited | Manufacturing | 2011 |
| Coob Associates Limited | Professional & scientific | 2003 |
| Cool-Lec Holdings Ltd | Financial services | 2020 |
| Cool-Lec Ltd | Administrative & support | 2008 |
| Coolest Media Limited | Wholesale & retail | 2008 |
| Cooper Accounting Limited | Professional & scientific | 2021 |
| Cooper Travel Halifax Ltd | Administrative & support | 2019 |
| Coopson Ltd | Information & communication | 2013 |
| COP OR Drop Ltd. | Administrative & support | 2018 |
| Copley Builders Limited | Construction | 2009 |
| Copley Kitchens Limited | Professional & scientific | 2014 |
| Copley Motors Limited | Wholesale & retail | 1976 |
| Copper-Node Web Development Ltd | Information & communication | 2018 |
| Copperwood Properties Ltd | Real estate | 2017 |
| Coppice View Dental (Harrogate) Limited | Health & social care | 2020 |
| Coralcast Limited | Wholesale & retail | 1991 |
| Cordelia Jones Hairdressing Limited | Other services | 2012 |
| Core Pipework Solutions Ltd | Construction | 2025 |
| Corksol Contracting Limited | Construction | 2024 |
| Corksol UK Ltd | Construction | 2017 |
| Corn Mill Property Associates Limited | Households | 2003 |
| Corner Shop Basny Boozer Limited | Transport & logistics | 2011 |
| Corton Dynamics Limited | Other services | 2024 |
| Corvus Electrical Services Limited | Construction | 2018 |
| COSMETICS4TRUE Limited | Wholesale & retail | 2022 |
| Cosmetox Ltd | Professional & scientific | 2020 |
| Cosmo Digi Ltd | Information & communication | 2025 |
| Cosmos Films Limited | Information & communication | 2020 |
| Cote Hill Carpets Limited | Wholesale & retail | 2018 |
| Coton and Ellis Autos Limited | Wholesale & retail | 2005 |
| Countryside Commercials (Yorkshire) Ltd | Wholesale & retail | 2018 |
| Countryside Living Limited | Construction | 2004 |
| County Customs Ltd | Wholesale & retail | 2023 |
| County Partnerships and Acquisitions Ltd | Real estate | 2018 |
| Covea Insurance PLC | Financial services | 1958 |
| Covers 33 Limited | Wholesale & retail | 2014 |
| Coview Solutions Limited | Professional & scientific | 2005 |
| Covéa Insurance Services Limited | Financial services | 1994 |
| Covéa Life Limited | Financial services | 1967 |
| COW & PIG Ltd | Hospitality | 2024 |
| COW Talk Ltd | Agriculture & fishing | 2014 |
| Cpmr Consulting Limited | Information & communication | 2025 |
| Crabtree Paston Ltd | Wholesale & retail | 2024 |
| Crackle Delta Ltd | Wholesale & retail | 2025 |
| Craft Associates Limited | Professional & scientific | 2025 |
| Craft Build Management Limited | Professional & scientific | 2025 |
| Craft Pizza & Grill Ltd | Hospitality | 2022 |
| Crafted Platter Limited | Hospitality | 2024 |
| Craftiosity Limited | Arts & recreation | 2017 |
| Cragg Vale Properties Ltd | Real estate | 2021 |
| Craggrunner Ltd | Arts & recreation | 2026 |
| Craig Engineering (UK) Limited | Manufacturing | 2009 |
| Craig Middleton Limited | Construction | 2012 |
| Craig Scott Limited | Construction | 2002 |
| Craig Taylor Building Contractors Ltd | Construction | 2020 |
| Craney Carig Scott Ltd | Wholesale & retail | 2025 |
| Craven Advisory Ltd | Administrative & support | 2025 |
| Craven Court Management (Halifax NO. 2) Limited | Households | 1996 |
| Craven Slater & Associates Limited | Financial services | 2003 |