| Coffee on Camden Limited | Hospitality | 2021 |
| Coffeecado Ltd | Hospitality | 2024 |
| Coldman & Kerr Limited | Construction | 1992 |
| Colinette Animal Services Limited | Agriculture & fishing | 2026 |
| College Racing (Beckenham) Limited | Real estate | 1998 |
| Coltad Ltd | Real estate | 2017 |
| Comfort Care Homes (Plas Y Bryn) Limited | Health & social care | 2013 |
| Comfy Retreat Limited | Real estate | 2025 |
| Companion Group Ltd | Information & communication | 2022 |
| Computer Operations Support Services Limited | Information & communication | 1987 |
| Comtech SVS Limited | Construction | 2020 |
| Comx Professional Services Limited | Extraterritorial | 2012 |
| Comxps Ltd | Professional & scientific | 2012 |
| Connacht Property & Developments Ltd | Construction | 2012 |
| Connect Solutions Limited | Information & communication | 2021 |
| Conrad Welch Freelance Ltd | Arts & recreation | 2014 |
| Construction Engineering Services Ltd | Professional & scientific | 2020 |
| CONSUL2PROCURE Ltd | Professional & scientific | 2026 |
| CONSULT30 Ltd | Professional & scientific | 2023 |
| Continuum IT Services Ltd | Professional & scientific | 2024 |
| Cook and Matthews Sport Limited | Wholesale & retail | 2010 |
| Cooper Clark Limited | Professional & scientific | 2010 |
| Cornel Oanta Limited | Transport & logistics | 2016 |
| Cornel Schalkwyk Travel Ltd | Administrative & support | 2023 |
| Cornerstone Legacy Holdings Ltd | Construction | 2025 |
| Costin Consultancy Ltd | Professional & scientific | 2025 |
| Countryside Renewables Ltd | Energy | 2013 |
| Cpss Consultancy Service Limited | Professional & scientific | 2019 |
| Crab Partnership LLP | | 2016 |
| Create the Image Productions Ltd | Professional & scientific | 2015 |
| Creative Buzz Ltd | Professional & scientific | 2023 |
| Creative Decorating Solutions Ltd | Construction | 2026 |
| Credit Collections Leeds Limited | Professional & scientific | 1981 |
| Credit Recovery Systems Limited | Administrative & support | 1978 |
| Creed DRY Cleaning Limited | Administrative & support | 2008 |
| CRH Roofing Ltd | Construction | 2025 |
| Crimson Night Limited | Administrative & support | 2014 |
| Croft Close Management Company Limited | Households | 2012 |
| Crown Lawns Ltd | Other services | 2006 |
| Crownplan Estates Limited | Real estate | 2003 |
| CRS Creative Recruitment Solutions Ltd | Professional & scientific | 2023 |
| Crs.Insure Limited | Financial services | 2022 |
| CSS Investments Ltd | Real estate | 2020 |
| Cunoil Consulting Limited | Professional & scientific | 2021 |
| CUP Yours Ltd | Manufacturing | 2020 |
| Curran & Pinner Limited | Real estate | 2007 |
| Current Development Limited | Construction | 1997 |
| Custos Care Ltd | Health & social care | 2021 |
| CWH Advisory Ltd | Professional & scientific | 2023 |
| Cyber Security Systems Ltd | Administrative & support | 2024 |
| D Howell Maintenance Ltd | Construction | 2015 |
| D Montague Plumbing & Heating Ltd | Construction | 2018 |
| D-Squared Solutions Limited | Information & communication | 2010 |
| Dangerous Words Limited | Professional & scientific | 2020 |
| Dani Luna Ltd | Education | 2019 |
| Danisman Limited | Administrative & support | 2011 |
| Danson Trading Limited | Wholesale & retail | 2024 |
| Dantegj Limited | Real estate | 2016 |
| Darbar Building Services Limited | Construction | 2025 |
| Darkins Enterprises Ltd | Professional & scientific | 2019 |
| DAS 4 Consulting Limited | Real estate | 2010 |
| Dascpa Limited | Professional & scientific | 2023 |
| Data Analysis and Insights Ltd | Information & communication | 2017 |
| Dathka Digital Limited | Information & communication | 2018 |
| Dave Warren Editing Ltd | Information & communication | 2024 |
| David Ball Limited | Arts & recreation | 2017 |
| David Johnson (Golf) Limited | Arts & recreation | 1989 |
| David Johnson (Holdings) Limited | Arts & recreation | 1993 |
| David Lilburn Watson Consulting Limited | Professional & scientific | 2022 |
| David Mccarthy Maintenance Limited | Construction | 2014 |
| Davidt Photography Limited | Professional & scientific | 2024 |
| Daviris Limited | Other services | 2015 |
| DCS Electrical Contractors Ltd | Construction | 2022 |
| DD Surveyors Ltd | Construction | 2014 |
| Ddlh Projects Limited | Professional & scientific | 2023 |
| DE Montfort College Ltd | Education | 2014 |
| Dean Rose Holdings Ltd | Other services | 1996 |
| Dees.Gp Limited | Wholesale & retail | 2024 |
| Denoel Ltd | Professional & scientific | 2017 |
| Design United Ltd | Professional & scientific | 2013 |
| Detami Ltd | Real estate | 2021 |
| Devalia Brothers Limited | Other services | 2023 |
| Devalia Consulting Limited | Health & social care | 2012 |
| Devalia Holdings Limited | Wholesale & retail | 2019 |
| Devfinn Ltd | Information & communication | 2022 |
| Devon Advisory Ltd | Administrative & support | 2020 |
| Devops and Linux Solutions Ltd | Information & communication | 2018 |
| Dexter Cornerstone Limited | Professional & scientific | 2025 |
| Dhawk Holdings Ltd | Information & communication | 2026 |
| DHB Project Services Limited | Real estate | 2022 |
| Dial Investments Developments Limited | Construction | 2021 |
| Dial Investments Holding Limited | Real estate | 2018 |
| Dial Investments Limited | Real estate | 1959 |
| Diamond Fire Stopping Limited | Public administration | 2024 |
| Diamond Scaffolding (South East) Limited | Construction | 2012 |
| Digital Munkey Limited | Administrative & support | 2013 |
| Dinoel Group Limited | Financial services | 2026 |
| Directfield Limited | Real estate | 2000 |
| Dmwslegal Limited | Professional & scientific | 2018 |
| DNL Homes Ltd | Real estate | 2018 |