| Convert & Measure Limited | Information & communication | 2013 |
| Converting Space Ltd | Construction | 2000 |
| Convicient Heating Solutions Ltd | Other services | 2023 |
| Cooden Investments Limited | Professional & scientific | 2014 |
| Cook & Crossman Ltd | Construction | 2017 |
| Cook Marketing Ltd | Wholesale & retail | 2025 |
| Cook Recruitment Group Ltd | Professional & scientific | 2018 |
| Cook Rental Properties Ltd | Real estate | 2020 |
| Cookbot Ltd | Other services | 2024 |
| Cookies by Double M Ltd | Manufacturing | 2023 |
| Cookieyes Limited | Information & communication | 2020 |
| Cooksport Limited | Manufacturing | 2009 |
| Cool Classics (MK) Ltd | Wholesale & retail | 2020 |
| Cool Ice MAN Enterprise Ltd | Hospitality | 2018 |
| Cool Motion Refrigerated Vehicle Rental Limited | Extraterritorial | 2016 |
| Cool Stuff Trading Ltd | Wholesale & retail | 2024 |
| COOL2COLLECT Limited | Wholesale & retail | 2009 |
| Coolfinish Body Repairs Ltd | Wholesale & retail | 2020 |
| Cooper & Hawkins Limited | Real estate | 2012 |
| Cooper Lomaz Recruitment Limited | Administrative & support | 1997 |
| Cooper Ward Engineering Limited | Professional & scientific | 2002 |
| Coordinated Care Ltd | Health & social care | 2024 |
| Coowei International Courier Limited | Transport & logistics | 2025 |
| Copeland & Company (MK) Limited | Professional & scientific | 2009 |
| Copeland Blue Limited | Professional & scientific | 2008 |
| Copenhagen Collections Limited | Wholesale & retail | 2015 |
| Copiam Medical Solutions Limited | Administrative & support | 2018 |
| Coplan Limited | Wholesale & retail | 1987 |
| Copper Monkey Productions Limited | Information & communication | 2002 |
| Copper Otter Marketing Limited | Professional & scientific | 2024 |
| Copperhouse Apartments Ltd | Households | 2023 |
| Copperhouse Living Limited | Real estate | 2025 |
| Copperhouse Residences Limited | Real estate | 2026 |
| Copperhouse Ventures Limited | Real estate | 2024 |
| Coppice Chippy Ltd | Hospitality | 2020 |
| Cora IND Limited | Other services | 2019 |
| Coral Payne Security Solutions Ltd | Administrative & support | 2026 |
| Corbun Projects Limited | Professional & scientific | 2026 |
| Cordant Cleaning Limited | Administrative & support | 2020 |
| Cordant Security Limited | Administrative & support | 2020 |
| Core Blimey (UK) Limited | Construction | 2008 |
| Core DNA Energy Solutions Ltd | Professional & scientific | 2015 |
| Core Fiscal Limited | Professional & scientific | 2025 |
| Core Highways (Barrier) Limited | Construction | 1983 |
| Core Highways (Signs) Limited | Transport & logistics | 2008 |
| Core Highways (Southeast) Limited | Transport & logistics | 2017 |
| Core Highways (Traffic Management) Limited | Administrative & support | 2002 |
| Core Highways Acquisitions Limited | Financial services | 2018 |
| Core Highways Group Limited | Financial services | 2018 |
| Core Highways Holdings Limited | Construction | 1982 |
| Core Issue Consulting Limited | Information & communication | 2004 |
| Core Residential Lettings Limited | Real estate | 2017 |
| Core SIX Limited | Real estate | 2026 |
| CORE650 Ltd | Arts & recreation | 2018 |
| Core: Connecting Repositories Ltd | Information & communication | 2025 |
| Corebalance Consultancy Limited | Professional & scientific | 2024 |
| Coredata Solutions Limited | Information & communication | 2000 |
| Coreground Engineering Ltd | Construction | 2026 |
| Corepro Build Ltd | Construction | 2018 |
| Corepro Living Ltd | Hospitality | 2026 |
| Corepro Ltd | Financial services | 2014 |
| Corinna Consulting Limited | Professional & scientific | 2013 |
| Corkett Comet Ltd | Hospitality | 2024 |
| Corkrend Limited | Construction | 2023 |
| Corlato Limited | Information & communication | 2015 |
| Corn Enterprises Limited | Real estate | 2019 |
| Cornell Recruitment Limited | Professional & scientific | 2012 |
| Cornerstone Heights Limited | Real estate | 2018 |
| Cornerstone Network Ltd | Real estate | 2026 |
| Cornerstone Plastering Ltd | Construction | 2025 |
| Cornerstone Properties and Renovations Limited | Real estate | 2021 |
| Cornerstone Trading (MK) Limited | Real estate | 1989 |
| Cornpastie Ltd | Construction | 2025 |
| Coro Holdings Ltd | Administrative & support | 2017 |
| Coronation Consulting Limited | Information & communication | 2019 |
| Corporate & Fiduciary Services Limited | Information & communication | 2014 |
| Corporate & Financial Services Limited | Financial services | 2002 |
| Corporate Advisory Limited | Professional & scientific | 2020 |
| Corporate Cafes and Catering Ltd | Hospitality | 2023 |
| Corporate Catering and Cafes 2 Ltd | Hospitality | 2025 |
| Corporate Fitness and Wellbeing Ltd | Other services | 2020 |
| Corporate Mobile Communications Limited | Wholesale & retail | 1993 |
| Corporatefaculty Limited | Information & communication | 2014 |
| Corporater UK Ltd | Information & communication | 2016 |
| Correct Accountants Ltd | Professional & scientific | 2020 |
| Corrosion Radar Limited | Professional & scientific | 2017 |
| Corunna Communications Ltd | Information & communication | 2019 |
| Corvette ARC Limited | Financial services | 2021 |
| Corvette Birmingham Limited | Financial services | 2021 |
| Corvette Bournemouth Limited | Financial services | 2021 |
| Corvette Capital Limited | Financial services | 2019 |
| Corvette Crown (Birmingham) Holdings Limited | Construction | 2021 |
| Corvette Crown (Bournemouth) Holdings Limited | Construction | 2021 |
| Corvette Crown (Leicester) Holdings Limited | Construction | 2021 |
| Corvette Leicester Limited | Financial services | 2021 |
| Corzo & Wood Limited | Wholesale & retail | 2017 |
| COS Mobile Tyre Fitting Limited | Wholesale & retail | 2025 |
| Cosa Clothing Nostra Ltd | Wholesale & retail | 2024 |
| Cosford Property Company Limited | Real estate | 1981 |
| Cosgrove Green Burial Meadow Limited | Other services | 2018 |