| C&C Kitchens Cardiff Limited | Manufacturing | 2017 |
| Canimsin Limited | Hospitality | 2023 |
| Capital Plumbing Limited | Construction | 2017 |
| Capitol Services Limited | Construction | 2002 |
| Cardiff Food Store Limited | Wholesale & retail | 2018 |
| Cassius Consultancy Limited | Professional & scientific | 2015 |
| CD Auto Trade Limited | Wholesale & retail | 2019 |
| Cellsway Limited | Manufacturing | 2020 |
| Centrum Flux Ltd | Information & communication | 2010 |
| Cfwm Holdings Limited | Professional & scientific | 2014 |
| Charcot Leisure Ltd | Hospitality | 2017 |
| Charis Alexandra Training Ltd | Information & communication | 2020 |
| Chart Shipping (UK) Ltd | Professional & scientific | 2015 |
| Chelsea Vintners London Limited | Wholesale & retail | 2012 |
| Chequers Way Local Ltd | Wholesale & retail | 2023 |
| Chiswick Tyres Limited | Wholesale & retail | 2010 |
| Chlou Limited | Real estate | 2015 |
| Choice & Select Catering Ltd | Hospitality | 2023 |
| Choice Essential Ltd | Wholesale & retail | 2021 |
| Choueh Law Firm Ltd | Professional & scientific | 2023 |
| Chrisianna Properties Ltd | Real estate | 2019 |
| Christino Properties Limited | Real estate | 2017 |
| Chrome Property Investments Limited | Real estate | 2010 |
| Cibus Beverage Limited | Wholesale & retail | 2010 |
| City Electric Services Limited | Construction | 2011 |
| Classified Entertainment Limited | Arts & recreation | 2013 |
| Climatair Limited | Energy | 2023 |
| CM Collins Horticulture Limited | Administrative & support | 2014 |
| CMG Dental Services Ltd | Health & social care | 2018 |
| CNP ( London ) Ltd | Health & social care | 2024 |
| Coffee Break Expand Limited | Hospitality | 2014 |
| Coffee Talks Limited | Wholesale & retail | 2014 |
| Cokek Limited | Hospitality | 2018 |
| Colour & Clarity Jewellers Ltd | Wholesale & retail | 2025 |
| Compass Shipping & Trading (Chandlery) Limited | Transport & logistics | 1990 |
| Complete Branding Limited | Manufacturing | 2013 |
| Complete Clothing Limited | Extraterritorial | 2017 |
| Complex Distribution Limited | Wholesale & retail | 2011 |
| Copak Limited | Manufacturing | 2006 |
| Cosmo Property Limited | Other services | 2019 |
| Cosmopolitan DRY Cleaners Limited | Other services | 2018 |
| CP Surgical VET Limited | Professional & scientific | 2025 |
| Creative Link Ltd | Administrative & support | 2001 |
| Crimson Tear Tattoos Limited | Other services | 2018 |
| Crooner Limited | Real estate | 1995 |
| Cross Roads Properties London Ltd | Real estate | 2025 |
| Crossbrook Finance Ltd | Financial services | 2016 |
| Cyart Limited | Real estate | 2019 |
| Cyprus Garden Ltd | Hospitality | 2014 |
| D&D Restaurant Ltd | Hospitality | 2015 |
| D'Amico Logistica Limited | Professional & scientific | 2022 |
| D.E.S. Sports Management Limited | Information & communication | 2014 |
| Damlar Investment Limited | Construction | 2007 |
| Damlar Limited | Wholesale & retail | 2018 |
| DDS Autos Ltd | Wholesale & retail | 2025 |
| DEA Dent Limited | Health & social care | 2023 |
| DEA Global Ltd | Real estate | 2026 |
| Dealcrown Properties Limited | Real estate | 1988 |
| Deep END Projects Limited | Professional & scientific | 2010 |
| Dekor Plus Limited | Wholesale & retail | 2017 |
| Derwent Studios Limited | Information & communication | 2015 |
| Design Structure Ltd | Construction | 2025 |
| Diagnostic Services and Repairs Limited | Wholesale & retail | 2018 |
| Direct to Retail Limited | Professional & scientific | 2011 |
| DK Clinics Limited | Health & social care | 2021 |
| DKR Ltd | Households | 2023 |
| DM Marketing Consultancy Limited | Professional & scientific | 2015 |
| Doerte Waechter Limited | Professional & scientific | 2012 |
| Donti Limited | Health & social care | 2022 |
| Doriana Limited | Hospitality | 2010 |
| Dormplace Limited | Construction | 1999 |
| DR Maite Ferrin Limited | Health & social care | 2017 |
| Dragon London Limited | Wholesale & retail | 2016 |
| Drmj Ltd | Health & social care | 2024 |
| Drumarin Limited | Professional & scientific | 2011 |
| Duguid Anderson Ltd | Households | 2018 |
| Durum Ocakbasi Limited | Hospitality | 2016 |
| DW Publications Limited | Information & communication | 2013 |
| E. Gandolfi Limited | Manufacturing | 1949 |
| E.J. Trading and Catering Limited | Hospitality | 2019 |
| East Crescent Properties Ltd | Real estate | 2024 |
| Eaton Place Property Management Ltd | Households | 2019 |
| Ecomsom UK Limited | Wholesale & retail | 2025 |
| Efeco Properties Limited | Construction | 1978 |
| Efezade Mezze Grill Limited | Hospitality | 2019 |
| EJC Investments Limited | Real estate | 2016 |
| EJW Property (One) Limited | Real estate | 2013 |
| Ekol International Limited | Professional & scientific | 2020 |
| Elswick Developments Limited | Other services | 2017 |
| EM Abodes Limited | Real estate | 2016 |
| Emin & Salih Limited | Hospitality | 2019 |
| Enamelight Limited | Health & social care | 2009 |
| Encore Electrical Contractors Ltd | Construction | 2019 |
| Encore UK Estates Limited | Real estate | 2024 |
| Enkay Meats Ltd | Wholesale & retail | 2019 |
| ERA Supermarket Limited | Wholesale & retail | 2011 |
| Eren Emre Property Limited | Other services | 2006 |
| Erensa Ltd | Real estate | 2020 |
| Esen Property Limited | Real estate | 2024 |
| Esquire Building and Construction Ltd | Construction | 2018 |