| Creed Miles Investments Limited | Financial services | 2020 |
| Creed-Miles & SON Limited | Administrative & support | 2010 |
| Crew Clothing Co. Limited | Wholesale & retail | 1996 |
| Crew Clothing Holdings Limited | Wholesale & retail | 2006 |
| Crimson Art Ltd | Administrative & support | 2016 |
| Crimson Racing Limited | Professional & scientific | 2014 |
| Crimson Swordblade Limited | Real estate | 2004 |
| Cristall UN Limited | Other services | 2011 |
| Crol Group Limited | Hospitality | 2020 |
| Crol London Bridge Limited | Hospitality | 2024 |
| Cromwells Coffee Limited | Hospitality | 2025 |
| Cronlab Limited | Information & communication | 2010 |
| Cross Border Retail Limited | Real estate | 2017 |
| Cross Lanes Consultancy Ltd | Other services | 2013 |
| Crovenda Co. Ltd | Administrative & support | 2026 |
| Crowdable Limited | Financial services | 2023 |
| Crown Apartments Services Limited | Real estate | 2007 |
| Crown Manning Services Ltd | Administrative & support | 2010 |
| Crown Tailoring & DRY Cleaning Ltd | Other services | 2015 |
| Crownfast Properties Limited | Real estate | 1995 |
| Crownsett Properties Limited | Real estate | 2003 |
| Cruise Routes Limited | Administrative & support | 2025 |
| Crux IT Consulting Services Limited | Information & communication | 2019 |
| Cruz Properties Investment Ltd | Real estate | 2023 |
| Crystal Care Homes Ltd | Health & social care | 2007 |
| Crystal Laundry Services Limited | Other services | 1982 |
| Crystal Property Income Limited | Financial services | 2013 |
| CS Design & Construction Limited | Construction | 2026 |
| CTP London Ltd | Administrative & support | 2016 |
| Cull Associates Ltd | Information & communication | 2010 |
| Culross Limited | Real estate | 2014 |
| Cultural Action Hub CIC | Public administration | 2024 |
| Cupe Technology Limited | Information & communication | 2019 |
| Curious Content Limited | Professional & scientific | 2017 |
| Curo (Cobalt) Nominees 1 Limited | Real estate | 2008 |
| Curo (Cobalt) Nominees 2 Limited | Real estate | 2008 |
| Curo (West Campbell) LLP | | 2012 |
| Curo Capital Ltd. | Administrative & support | 2014 |
| Curo Charlotte House LLP | | 2011 |
| Curo Hotels Burnham GP Limited | Hospitality | 2017 |
| Curo Hotels Burnham LP | | 2017 |
| Curo Hotels Burnham Nominee Limited | Hospitality | 2017 |
| Curo Hotels Mansfield GP Limited | Hospitality | 2018 |
| Curo Hotels Mansfield LP | | 2018 |
| Curo Hotels Mansfield Nominee Limited | Hospitality | 2018 |
| Curo Property Funds LLP | | 2004 |
| Curu Media Ltd | Information & communication | 2011 |
| Custom Flooring Surrey Limited | Construction | 2024 |
| CVT Tyres Ltd | Wholesale & retail | 2025 |
| CXO Circle Limited | Professional & scientific | 2023 |
| Cyan Design Studio Ltd | Professional & scientific | 2012 |
| Cyanmar Limited | Professional & scientific | 2025 |
| Cycle Exchange Ltd | Wholesale & retail | 2013 |
| Cyrus Investment Asset Management Ltd | Construction | 2020 |
| D by D Limited | Professional & scientific | 2018 |
| D G Installations Surrey Ltd | Construction | 2020 |
| D Stanton Consulting Limited | Information & communication | 2025 |
| D&I Associates Ltd | Professional & scientific | 2023 |
| D'S Artisan Bakery Limited | Manufacturing | 2025 |
| D-Ride Moto Ltd | Wholesale & retail | 2025 |
| D.M. Spragg Limited | Construction | 1957 |
| DA Capo Partners Ltd | Information & communication | 2010 |
| DA Consultants Ltd | Professional & scientific | 2024 |
| DA8 Properties Ltd | Construction | 2018 |
| Dabas Solutions Limited | Professional & scientific | 2005 |
| DAH Image Limited | Professional & scientific | 2023 |
| Dahab Capital Ltd | Wholesale & retail | 2021 |
| Daily Runner Limited | Wholesale & retail | 2026 |
| Dairo Ltd | Hospitality | 2020 |
| Daisy Management Limited | Professional & scientific | 2009 |
| Dalavich Limited | Administrative & support | 2004 |
| Dalemead Care Home Limited | Health & social care | 2009 |
| DAM and SUD Ltd | Real estate | 2017 |
| Dama Tech Ltd. | Administrative & support | 2019 |
| Damavand Properties Ltd | Real estate | 2025 |
| DAN Cafe Ltd | Hospitality | 2016 |
| DAN Heighes Consulting Ltd | Hospitality | 2018 |
| DAN Reed Services Ltd | Professional & scientific | 2021 |
| Dandelions Investment Limited | Real estate | 2020 |
| Danebury Research Ltd | Professional & scientific | 2022 |
| Danehurst Court (Epsom) Limited | Households | 1969 |
| Dani Property Investments Ltd | Real estate | 2024 |
| Daniel Afshar Consulting Ltd | Professional & scientific | 2015 |
| Daniel Livingston Limited | Information & communication | 2023 |
| Daniel Negrin Consulting Ltd | Professional & scientific | 2022 |
| Daniel Quarter (Ealing) Management Limited | Households | 2005 |
| DAP Foods Ltd | Wholesale & retail | 2018 |
| Dartford DA1 Ltd | Real estate | 2015 |
| Dartford Karting Ltd | Wholesale & retail | 2003 |
| DAS Trade & Commerce Limited | Hospitality | 2013 |
| Daspeca Ltd | Health & social care | 2023 |
| Dass Investments UK Ltd | Real estate | 2025 |
| Data Operator Limited | Information & communication | 2024 |
| Datacentre and Cloud Services Limited | Information & communication | 2017 |
| Datadoor Limited | Information & communication | 2021 |
| Datatel Media Communications Ltd | Information & communication | 2003 |
| Daudt Mechanical Ltd | Construction | 2014 |
| Davenport Court Property Management Company Limited | Households | 2024 |
| David Andrews Radio Ltd | Information & communication | 2021 |
| David Howard Limited | Professional & scientific | 1997 |