| Cobco 702 Limited | Real estate | 2005 |
| Cobden Street Management Company Limited | Households | 1990 |
| Cobi Toys Limited | Administrative & support | 2017 |
| Coco Hire Group Ltd | Other services | 2017 |
| Cocoon Harrogate Ltd | Health & social care | 2022 |
| Code Assist Ltd | Information & communication | 2017 |
| Code One Development Ltd | Information & communication | 2021 |
| Code Strength Ltd | Information & communication | 2008 |
| Coderail Ltd | Information & communication | 2012 |
| Codogan Limited | Wholesale & retail | 2024 |
| Cogenic Limited | Real estate | 2001 |
| COL1N Limited | Extraterritorial | 2018 |
| Colak Grocery Ltd | Wholesale & retail | 2021 |
| Cold Bath Bakehouse Limited | Hospitality | 2025 |
| Cold Bath Brewing Company Limited | Manufacturing | 2017 |
| Cold Bath Cafe Ltd | Hospitality | 2025 |
| Cold Bath Consultants Ltd | Construction | 2024 |
| Cold Bath Interiors Limited | Professional & scientific | 2023 |
| Coldbath Coffee Ltd | Hospitality | 2026 |
| Coldbath Flooring Ltd | Wholesale & retail | 2019 |
| Coldstones Management Company Limited | Real estate | 2003 |
| Colin Cooper Dragonfly Football Consultancy Limited | Education | 2019 |
| Colin Findlay Consulting Ltd | Professional & scientific | 2022 |
| Collarov Limited | Real estate | 2000 |
| Colliers Surveyors Limited | Professional & scientific | 2021 |
| Collin Wood Management Company Limited | Households | 2021 |
| Collingwood Land Limited | Professional & scientific | 2025 |
| Cologne Holdings Ltd | Real estate | 2022 |
| Colonnade Court Management Limited | Households | 2004 |
| Colsh Limited | Extraterritorial | 2025 |
| Colt House Investments Limited | Real estate | 2000 |
| Colthurst Limited | Extraterritorial | 2026 |
| Colton Signs Ltd | Manufacturing | 2019 |
| Combination Design Studio Ltd | Professional & scientific | 2012 |
| Combined Academic Publishers Limited | Information & communication | 1997 |
| Comforting Hands Recruitment Ltd | Administrative & support | 2017 |
| Comic World Ltd | Extraterritorial | 2012 |
| Command Cognition Advisory Ltd | Professional & scientific | 2026 |
| Commerce Attractive Limited | Wholesale & retail | 1998 |
| Commercial Agents Limited | Extraterritorial | 2012 |
| Commercial Chimney Solutions Ltd | Administrative & support | 1998 |
| Commercial Disinfection Services Limited | Administrative & support | 2022 |
| Commercial Exchange Ltd | Wholesale & retail | 2025 |
| Commercial Investment Developments Limited | Construction | 2014 |
| Commercial Rescue Limited | Extraterritorial | 2012 |
| Commercial Wholesale Trading Limited | Wholesale & retail | 2000 |
| Communicating Energy Limited | Professional & scientific | 2025 |
| Communication IS Key Ltd | Wholesale & retail | 2024 |
| Community Catalysts C.I.C. | Other services | 2009 |
| Community Empowerment Leeds CIC | Hospitality | 2023 |
| Community Kids Leisure Limited | Wholesale & retail | 2020 |
| Community Oral Health Ltd | Education | 2026 |
| Community Social Relations Limited | Wholesale & retail | 2020 |
| Company Infrastructure Reviewers Limited | Wholesale & retail | 2024 |
| Compare Drawdown Ltd | Financial services | 2014 |
| Comparing Business Ltd | Wholesale & retail | 2024 |
| Compass Broker Holdings Limited | Financial services | 2016 |
| Compass Broker Networks Limited | Financial services | 2016 |
| Compass Corp UK Ltd | Administrative & support | 2014 |
| Compellor Ltd | Professional & scientific | 2019 |
| Complete Bio-Nutrient Solutions (Cbns) Limited | Agriculture & fishing | 2019 |
| Complete Eletrical Solutions Yorks Limited | Construction | 2021 |
| Complete Lean Solutions Limited | Professional & scientific | 2006 |
| Complete Mortgages (Harrogate) Ltd | Financial services | 2020 |
| Complete Recycling Services Limited | Wholesale & retail | 2018 |
| Completely Financial Services Limited | Financial services | 2004 |
| Complex Trauma Institute Ltd | Professional & scientific | 2020 |
| Compliabilitee Ltd | Other services | 2017 |
| Composite Holdings Limited | Extraterritorial | 2026 |
| Computerlinks (UK) Limited | Financial services | 1996 |
| Comtract Ltd | Administrative & support | 2010 |
| Concierge Camping Limited | Other services | 2014 |
| Concierge Glamping Limited | Hospitality | 2016 |
| Concilio Services Limited | Professional & scientific | 2015 |
| Concordia Projects Limited | Construction | 2016 |
| Conexxia Limited | Information & communication | 2023 |
| Confection by Design Limited | Manufacturing | 1998 |
| Conisance Limited | Professional & scientific | 2020 |
| Coniston Water Ltd | Administrative & support | 2002 |
| Connect Consulting Solutions Ltd | Information & communication | 2025 |
| Connectably Ltd | Information & communication | 2017 |
| Connectra Ltd | Financial services | 2025 |
| Connex South Eastern | Transport & logistics | 1995 |
| Connolly Real Estate Services Ltd | Real estate | 2026 |
| Conradd Limited | Extraterritorial | 2012 |
| Consciousgeneration Ltd | Wholesale & retail | 2021 |
| Consensus Politics Ltd | Information & communication | 2020 |
| Construction Group Consultancy Limited | Professional & scientific | 2002 |
| Construction Vision Solutions Ltd | Construction | 2021 |
| Constructions SA Ltd | Construction | 2025 |
| Constructprodesign Ltd | Construction | 2024 |
| Consumer Credit Compliance Limited | Administrative & support | 2013 |
| Consumer Credit Compliance Training Limited | Administrative & support | 2017 |
| Contact Training & Consultancy Limited | Administrative & support | 1996 |
| Contender Sporting Ltd | Agriculture & fishing | 2020 |
| Continental Luxury Limited | Extraterritorial | 2026 |
| Continental Prestige Limited | Extraterritorial | 2026 |
| Continued Care From Oakville Ltd | Health & social care | 2004 |
| Continuum Building Services Limited | Professional & scientific | 2026 |
| Controtax Ltd | Extraterritorial | 2022 |