| Criss Grove Management Company Limited | Real estate | 2007 |
| Critical Labs Ltd | Information & communication | 2025 |
| Critical Site Services Ltd | Construction | 2023 |
| Crm-Xe Services Ltd | Professional & scientific | 2022 |
| Croft Cars Limited | Wholesale & retail | 2024 |
| Croqueteria Limited | Hospitality | 2022 |
| Cross Lances Property Investments Limited | Real estate | 2018 |
| Crossbell Holdings Limited | Financial services | 2024 |
| Crossbell Limited | Wholesale & retail | 2002 |
| Crowdity Ltd | Wholesale & retail | 2010 |
| Crozier Design Studios Limited | Professional & scientific | 2017 |
| Crush Festival CIC | Arts & recreation | 2024 |
| CSG Car Sales Limited | Extraterritorial | 2014 |
| CSG Motor Company Limited | Wholesale & retail | 2003 |
| CST Assets Limited | Information & communication | 2018 |
| Cswt Ltd | Manufacturing | 2018 |
| Cuadro Holdings Limited | Financial services | 2019 |
| Cuadro Limited | Financial services | 2012 |
| Cufflink.Io Ltd | Information & communication | 2018 |
| Culvert Road 58 Limited | Real estate | 2016 |
| Cumbers Building & Carpentry Ltd | Construction | 2024 |
| Curious Equity Ltd | Financial services | 2021 |
| Curious Real Estate Ltd | Professional & scientific | 2021 |
| CUT N Create Ltd | Manufacturing | 2023 |
| Cyber RE Limited | Financial services | 2016 |
| Cyhm Limited | Information & communication | 2021 |
| D Hampshire Consulting Ltd | Other services | 2014 |
| D J Chapman Electrical Ltd | Construction | 2015 |
| D J Portfolio Limited | Wholesale & retail | 2008 |
| D Marway Limited | Administrative & support | 2018 |
| D P Mensah Consulting Limited | Professional & scientific | 2013 |
| D Serenity Homes Limited | Construction | 2025 |
| D&Juk Ltd | Wholesale & retail | 2016 |
| D.L.C.Estates,Limited | Real estate | 1947 |
| D4 Property Management Limited | Real estate | 2018 |
| Dalesbrow Housing Limited | Real estate | 2020 |
| Daleside Construction Limited | Construction | 2026 |
| Daleside Property Investments Ltd | Real estate | 2013 |
| Dallant UK Ltd | Extraterritorial | 1990 |
| Damage-Inc Limited | Administrative & support | 2022 |
| Dana Salon Limited | Other services | 2022 |
| Dancepoint Limited | Other services | 1993 |
| Daniel Todd Ltd | Information & communication | 2008 |
| Daniel William Estate Management Ltd | Real estate | 2025 |
| Danis Auto Centre Ltd | Wholesale & retail | 2022 |
| Danny Leigh Limited | Arts & recreation | 2003 |
| DAP Compass Consulting Ltd | Information & communication | 2025 |
| Dara-Pinnock Ltd | Hospitality | 2020 |
| Darling Beauty Limited | Other services | 2013 |
| Darling Beauty School Limited | Other services | 2013 |
| Darma Metals Ltd | Professional & scientific | 2019 |
| Dastar & Drapes Ltd | Wholesale & retail | 2025 |
| Data Perspectives Ltd | Other services | 2012 |
| Datasmith Partners Ltd | Information & communication | 2012 |
| Daughtrey Holdings Ltd | Real estate | 2021 |
| David Duncan Ltd | Professional & scientific | 2011 |
| David Limited | Information & communication | 1997 |
| David Lindsell Consultancy Limited | Professional & scientific | 2006 |
| David Radford Limited | Other services | 2011 |
| Davies Leslie-Smith Limited | Information & communication | 2020 |
| Davis - Law Associates Limited | Professional & scientific | 2012 |
| Davnis Canary Wharf Ltd | Construction | 2024 |
| Davnis Investments Ltd | Financial services | 2020 |
| Davnis ST Albans Ltd | Construction | 2021 |
| Dawson-Pick Associates Limited | Professional & scientific | 2010 |
| Dazzle Draws Limited | Arts & recreation | 2026 |
| DB Setfix Ltd | Construction | 2022 |
| DC Film Lighting Limited | Other services | 2012 |
| DC Plumbing & Heating Services Limited | Construction | 2007 |
| DCR Builders Ltd | Construction | 2025 |
| Decorum Partners London Limited | Administrative & support | 2019 |
| DEK Consulting Ltd | Professional & scientific | 2003 |
| Delice Foods (GX) Limited | Hospitality | 2024 |
| Delice Foods Limited | Hospitality | 2024 |
| Delivery Partnership Ltd | Professional & scientific | 2007 |
| Delivery Service Partners Ltd | Transport & logistics | 2021 |
| Delta 365 Limited | Information & communication | 2014 |
| Delta 365 Solutions Limited | Information & communication | 2019 |
| Delta 365 Talent Solutions Limited | Administrative & support | 2023 |
| Delta Synergistics Contracts Limited | Administrative & support | 2022 |
| Delta Synergistics Projects Limited | Administrative & support | 1996 |
| Deluxe Skin Clinic Limited | Other services | 2021 |
| DEN & Snow Estates Ltd | Real estate | 2025 |
| Denham Business Solutions Limited | Professional & scientific | 1997 |
| Denham Car Valeting Ltd | Administrative & support | 2020 |
| Denham Green Properties Limited | Real estate | 1998 |
| Denham Limited | Professional & scientific | 2025 |
| Dennkers Ltd | Information & communication | 2016 |
| Dentfix Limited | Wholesale & retail | 2000 |
| Dentfix PDR Ltd | Wholesale & retail | 2019 |
| Depairs Ltd | Wholesale & retail | 2023 |
| Derbyshire Property Development Ltd | Real estate | 2014 |
| DES Fuller Construction Limited | Construction | 2020 |
| Design With Soph Limited | Wholesale & retail | 2023 |
| Desons Limited | Wholesale & retail | 2008 |
| Devilfish Design Limited | Professional & scientific | 2006 |
| Devonshire Glass Centre Limited | Construction | 1986 |
| Dewry Holdings Limited | Financial services | 2022 |
| DFZ Consult Limited | Administrative & support | 2018 |
| DG Imports Limited | Wholesale & retail | 1995 |