| City Traxx Ltd | Administrative & support | 2018 |
| City Workwear Ltd | Wholesale & retail | 2017 |
| Civicore Networks Ltd | Construction | 2025 |
| Civil Debt & Bailiff Services Limited | Administrative & support | 2024 |
| CJ Hyde Ltd | Construction | 2026 |
| CJ Jetz Limited | Construction | 2001 |
| CJ Nelson Ltd | Water & waste | 2022 |
| Cjlites Ltd | Real estate | 2025 |
| CJM Recruitment Ltd | Administrative & support | 2024 |
| Cjnl Consultancy Limited | Professional & scientific | 2020 |
| Cjnl Investments Limited | Financial services | 2018 |
| CJP Group Projects Limited | Financial services | 2025 |
| CJP Northwest Limited | Construction | 2013 |
| CJP NW Limited | Construction | 2019 |
| CJS Retail Ltd | Wholesale & retail | 2024 |
| Cjuk Holdings a Limited | Financial services | 2017 |
| Cjuk Holdings Limited | Financial services | 2017 |
| Cjwc Ltd | Wholesale & retail | 2014 |
| CK Business Consultants Limited | Information & communication | 2024 |
| CK Sports Limited | Wholesale & retail | 2018 |
| CK Take Away (Blackburn) Ltd | Hospitality | 2019 |
| CKM Property Solutions Limited | Real estate | 2017 |
| CL & MT Holdings Limited | Financial services | 2023 |
| Cl&T Holdings Ltd | Professional & scientific | 2026 |
| Clarence Jones (Machinery) Company Limited | Wholesale & retail | 1976 |
| Clarendon Two Investments Ltd | Real estate | 2026 |
| Claritel IT Limited | Administrative & support | 2023 |
| Claritel Limited | Information & communication | 2011 |
| Class Autos Ltd | Wholesale & retail | 2019 |
| Classic Conservatory Systems Limited | Manufacturing | 2002 |
| Classic Fireworks Limited | Wholesale & retail | 2002 |
| Classic Leather Ltd | Wholesale & retail | 2025 |
| Classic Workwear Ltd | Manufacturing | 2019 |
| Classy Gems Ltd | Wholesale & retail | 2024 |
| Clawz SG Limited | Administrative & support | 2020 |
| Clayton HEY Fold Farm Residents Limited | Real estate | 2010 |
| Clayton Hill Properties Ltd | Real estate | 2022 |
| Clean Energy 4 YOU Limited | Construction | 2024 |
| Clean Envy Limited | Administrative & support | 2016 |
| Clean With Care TM Limited | Administrative & support | 2025 |
| Clear Deal Ltd | Wholesale & retail | 2025 |
| Clear Flow Drainage & Civil Engineering Ltd | Construction | 2025 |
| Clear Health UK - Limited | Health & social care | 2026 |
| Clear Mental Health Ltd | Health & social care | 2026 |
| Clear Prospects Limited | Manufacturing | 2001 |
| Clear Waste Services Ltd | Professional & scientific | 2004 |
| Clearance Central Ltd | Wholesale & retail | 2026 |
| Clearance Factor Limited | Wholesale & retail | 2017 |
| Clearercare Lancashire Limited | Health & social care | 2021 |
| Clears WAX Removal Ltd | Administrative & support | 2021 |
| Cleggs Construction UK Ltd | Construction | 2022 |
| Cleggs Group Ltd | Other services | 2022 |
| Cleggs Properties Ltd | Other services | 2024 |
| Clemens Court Management Company Ltd | Hospitality | 2003 |
| Clemson Trading Ltd | Health & social care | 2025 |
| Clerkenwell Sound Collective Ltd | Information & communication | 2019 |
| Cleverup Limited | Education | 2025 |
| Clhm Steel Limited | Real estate | 2022 |
| Click Rush Ltd | Wholesale & retail | 2025 |
| Click Telecom Ltd | Information & communication | 2022 |
| CLICK&SHIP14 Limited | Wholesale & retail | 2025 |
| Cliff Crook & Sons (Blackburn) Limited | Wholesale & retail | 2002 |
| Clifton Developments Limited | Real estate | 1981 |
| Clifton Gray Limited | Administrative & support | 2017 |
| Clifton Heights (Isleworth) Management Company Limited | Households | 2017 |
| Clifton Vale Property Ltd | Real estate | 2025 |
| Clinpharma Innovations Limited | Professional & scientific | 2023 |
| Clitheroe Collectables Limited | Wholesale & retail | 2015 |
| Clitheroe Precision Machining Limited | Manufacturing | 2025 |
| Clitheroe Psychotherapy Services Ltd | Health & social care | 2024 |
| Clitheroe Rugby Union Football Club Limited | Arts & recreation | 2011 |
| Clock Garage Tyres Limited | Wholesale & retail | 2014 |
| Clock Tower Legal Ltd | Professional & scientific | 2023 |
| Cloete Laundry Services Ltd | Other services | 2026 |
| Clothe Co Ltd | Wholesale & retail | 2024 |
| Cloud Booth Ltd | Wholesale & retail | 2023 |
| Cloud Coating Limited | Manufacturing | 2026 |
| Cloud Feathers Ltd | Wholesale & retail | 2025 |
| Cloud Ledgers Ltd | Professional & scientific | 2024 |
| Cloud OS Workspace Limited | Information & communication | 2016 |
| Cloud Packaging Ltd | Administrative & support | 2019 |
| Cloud Partners NW Ltd | Wholesale & retail | 2025 |
| Cloud Products Ltd | Wholesale & retail | 2015 |
| Cloud Stacks Artisan Ltd | Manufacturing | 2025 |
| Cloud Walk CS Ltd | Administrative & support | 2026 |
| Cloudfoods Limited | Hospitality | 2025 |
| Clovelly Builders Limited | Construction | 2003 |
| CLS & HEZ Limited | Real estate | 2025 |
| Club 2 Thrive Ltd | Financial services | 2026 |
| Club DE Calle Ltd | Wholesale & retail | 2026 |
| Cluster Club Ltd | Manufacturing | 2021 |
| Clydemotors Limited | Wholesale & retail | 2019 |
| Clydesdale (Lancs) Motors Ltd | Wholesale & retail | 2025 |
| CML Clothing Ltd | Wholesale & retail | 2022 |
| CML Design Web Services Ltd | Other services | 2012 |
| CMM Logistics Ltd | Transport & logistics | 2015 |
| CMM Northwest Ltd | Construction | 2013 |
| CN Commercials Limited | Wholesale & retail | 2009 |
| CNC Wood Ltd | Professional & scientific | 2022 |
| Cnqrd Ltd | Administrative & support | 2026 |