| Continental Tailor Ltd | Wholesale & retail | 2025 |
| Continuous Motion Ltd | Arts & recreation | 2025 |
| Continuum 8 Limited | Real estate | 2021 |
| Continuum Space Solutions Ltd | Real estate | 2022 |
| Contour Coffee Ltd | Manufacturing | 2025 |
| Contover Trading Co Limited | Real estate | 1939 |
| Contra Productions Ltd | Arts & recreation | 2023 |
| Contract & Construction Consultants (Southern) Ltd | Professional & scientific | 2010 |
| Contract & Construction Consultants Ltd | Professional & scientific | 2000 |
| Contract Dispute Resolution Limited | Professional & scientific | 2004 |
| Contract Drylining Ltd | Construction | 2018 |
| Contract Electrical Services South West Limited | Administrative & support | 2003 |
| Contract King Ltd | Professional & scientific | 2025 |
| Contract Technology Limited | Real estate | 1972 |
| Contracting Synergy Ltd | Professional & scientific | 2019 |
| Contractservicessw Ltd | Professional & scientific | 2021 |
| Contrarian Capital Limited | Financial services | 2023 |
| Contrivance Ltd | Manufacturing | 2023 |
| Control & Panel Services (South West) Ltd | Manufacturing | 2011 |
| Control Microsystems Ltd | Manufacturing | 1989 |
| Controlcraft Ltd | Professional & scientific | 2024 |
| Controlled Consulting Ltd | Professional & scientific | 2012 |
| Controstar Investments Limited | Real estate | 2014 |
| Conundrum Consultancy Ltd | Professional & scientific | 2025 |
| Conundrum Properties Ltd | Real estate | 2023 |
| Conventus Solutions Limited | Administrative & support | 2014 |
| Conventus Technical Solutions Limited | Extraterritorial | 2015 |
| Conver Holdings Ltd | Financial services | 2024 |
| Conver Properties Limited | Construction | 1972 |
| Conversational AI Ltd | Professional & scientific | 2015 |
| Convertdata Ltd | Extraterritorial | 2013 |
| Convertertechnology (UK) Private Limited | Information & communication | 2008 |
| Conveyancing Searches Service Limited | Real estate | 2012 |
| Conveynext Ltd | Administrative & support | 2025 |
| Conveyor Maintenance Services Limited | Manufacturing | 2017 |
| Conway Read Partnership Limited | Professional & scientific | 2011 |
| Conwray Solutions Limited | Administrative & support | 2025 |
| Conxiea Ltd | Information & communication | 2026 |
| Conygre House Management Company Limited | Households | 2018 |
| Coobo Limited | Real estate | 2023 |
| Cook & Cardenas Ltd | Information & communication | 2023 |
| Cook & Edwards Ltd | Professional & scientific | 2016 |
| Cook & Harris Ltd. | Construction | 1997 |
| Cook and Copp Holding Ltd | Real estate | 2015 |
| Cook and Copp Limited | Real estate | 2011 |
| Cook Capital Limited | Real estate | 2022 |
| Cook Corporate Ltd | Professional & scientific | 2018 |
| Cook Electrical Services Ltd | Construction | 2015 |
| Cook Holdings Limited | Professional & scientific | 2008 |
| Cook Solutions Limited | Professional & scientific | 2024 |
| Cooke Painter Limited | Professional & scientific | 2008 |
| Cooked Properties Ltd | Real estate | 2026 |
| Cookin on GAS Ltd | Other services | 2006 |
| Cooking IT Corporate Events Ltd. | Arts & recreation | 2024 |
| Cookpad Limited | Information & communication | 2015 |
| Cooks Property Maintenance Ltd | Professional & scientific | 2012 |
| Cookson & Tickner Limited | Administrative & support | 2012 |
| Cool - Crest Refrigeration Limited | Manufacturing | 1990 |
| Cool Approach Limited | Administrative & support | 2007 |
| Cool Flush Ltd | Professional & scientific | 2025 |
| Cool Lets Ltd | Real estate | 2015 |
| Cool Logistics Limited | Extraterritorial | 2014 |
| Cool Solutions Refrigeration and Air Conditioning Limited | Construction | 2006 |
| Cool Ventures Limited | Professional & scientific | 2011 |
| Cool-Rite Air Conditioning Limited | Construction | 2001 |
| Coola Classics Vehicle Restoration Limited | Wholesale & retail | 2013 |
| Coolbison Limited | Information & communication | 2021 |
| Coole Insight Ltd | Professional & scientific | 2018 |
| Coolgas Limited | Manufacturing | 1993 |
| Cooling Property Investments Ltd | Real estate | 2026 |
| Coolink Limited | Construction | 2010 |
| Coolstream (UK) Ltd | Energy | 2013 |
| Coolstream Vent (SW) Ltd | Manufacturing | 2022 |
| Coombe Clinic Limited | Health & social care | 2013 |
| Coombe Dingle Property Management Ltd | Households | 2025 |
| Coombe Rock (Management) Company Limited | Households | 1973 |
| Coombend House RTM Company Ltd | Households | 2018 |
| Coombs Properties Limited | Real estate | 2024 |
| Coomer Holdings Limited | Real estate | 2007 |
| Coomer Property Services Limited | Real estate | 2016 |
| Cooper & Koch Ltd | Professional & scientific | 2024 |
| Cooper Financials UK Limited | Professional & scientific | 2021 |
| Cooper Investment Partners Ltd | Other services | 2016 |
| Cooper Landscape Planning Ltd | Administrative & support | 2019 |
| Cooperage Road Management Ltd | Households | 2006 |
| Coopers Construction Services Ltd | Construction | 2020 |
| Coopers Yard (Newark) Management Company Limited | Administrative & support | 2003 |
| Coordineight Limited | Financial services | 2004 |
| Cootes Veterinary Clinic Limited | Extraterritorial | 2006 |
| Copa Solutions Ltd | Professional & scientific | 2020 |
| Copa-Data UK Limited | Administrative & support | 2007 |
| Copeland Construction Limited | Construction | 2010 |
| Copesticks Ltd | Professional & scientific | 2011 |
| Copley Square Management Company Limited | Real estate | 2004 |
| Coppard Group Ltd | Construction | 2025 |
| Copper Ashton Developments (Backwell) Limited | Construction | 2022 |
| Copper Ashton Developments Limited | Construction | 2022 |
| Copper Ashton Holdings Limited | Financial services | 2022 |
| Copper Ashton Properties Limited | Real estate | 2019 |
| Copper Coffee Ltd | Hospitality | 2022 |