| Creigiau Community Hub Ltd | Arts & recreation | 2016 |
| Creigiau Petanque Club Limited | Arts & recreation | 2022 |
| Crofta Cottages Limited | Real estate | 2024 |
| Crooked Cameras Ltd | Information & communication | 2024 |
| Cross Ecology Ltd | Professional & scientific | 2024 |
| Crossways Investments Limited | Information & communication | 2017 |
| Crossways Maintenance Limited | Administrative & support | 1979 |
| Crown Llandow Limited | Financial services | 2026 |
| Crown Resources Limited | Wholesale & retail | 2005 |
| Cruck Cottages Leasehold Limited | Real estate | 2023 |
| Crux Wheels Ltd | Professional & scientific | 2020 |
| Crystal Squid Limited | Information & communication | 2003 |
| Ctronix Limited | Manufacturing | 1979 |
| Cucina Caruso Ltd | Information & communication | 2017 |
| Curley Locks Ltd | Administrative & support | 2012 |
| CWI (Neath) Limited | Construction | 2026 |
| Cwtch Care Ltd | Health & social care | 2018 |
| Cygnus Airconditioning Limited | Construction | 2004 |
| Cygnus HV & Electrical Limited | Manufacturing | 2025 |
| D R Asset Management Ltd | Financial services | 2018 |
| D. Brown & Sons Limited | Wholesale & retail | 1947 |
| D.I. Glover Ltd | Construction | 2025 |
| D.P.W. Projects Limited | Professional & scientific | 2007 |
| D27 Estates Ltd | Professional & scientific | 2011 |
| DAI Camera Limited | Information & communication | 2019 |
| Damar Holdings Ltd | Financial services | 2023 |
| Daniel R. Stubbings Property Investments Ltd | Real estate | 2023 |
| Dantax Ltd | Administrative & support | 2012 |
| Data IT Consultancy Limited | Information & communication | 2007 |
| Data Rapids Limited | Information & communication | 2023 |
| Dave Dearnaley Guitars Limited | Wholesale & retail | 2002 |
| David Birt Professional Services Limited | Real estate | 1997 |
| David Clements Ecology Limited | Professional & scientific | 2003 |
| Davies Universal Ltd | Health & social care | 2023 |
| Davimore Properties Limited | Real estate | 2002 |
| DE Monde Property Limited | Real estate | 2018 |
| Delyn Properties (UK) Ltd | Real estate | 2021 |
| Delyn Properties LLP | | 2006 |
| Denman & Sons Builders Merchants Limited | Construction | 1949 |
| Denrose Projects Limited | Construction | 2007 |
| Derlayne Real Estate Limited | Real estate | 2023 |
| Deryn Developments Limited | Financial services | 1987 |
| Devalia Property Investments Ltd | Real estate | 2023 |
| DHN Management Limited | Transport & logistics | 2000 |
| Diagram Creative Ltd | Wholesale & retail | 2014 |
| Diligent DRONES24 Ltd | Professional & scientific | 2024 |
| Dillon IT Services Ltd | Information & communication | 2011 |
| Dirwest CYF | Wholesale & retail | 2025 |
| Disney Blinds Limited | Other services | 2002 |
| Dividefind Limited | Water & waste | 1991 |
| Dljames Roofing Ltd | Construction | 2026 |
| Dolun Developments (South Wales) Limited | Real estate | 2011 |
| DPW Consulting Limited | Professional & scientific | 2006 |
| DR Kelly Medical Services Limited | Health & social care | 2025 |
| DR R Corkill Ltd | Health & social care | 2022 |
| Dragon Fleet Ltd | Transport & logistics | 2021 |
| Dragon Radio Limited | Information & communication | 2014 |
| Dreman Limited | Information & communication | 2021 |
| DS Energy Solutions Limited | Professional & scientific | 2022 |
| Durbin Investments Ltd | Real estate | 2007 |
| EA BIZ Services Ltd | Administrative & support | 2025 |
| Easicook Catering Equipment Ltd | Manufacturing | 2013 |
| East Llanion Marine Limited | Other services | 1976 |
| East Street Holdings Ltd | Real estate | 2018 |
| Eco Passive Homes Limited | Construction | 2020 |
| Ecotherm Bathrooms and Heating Ltd | Construction | 2022 |
| Eden Cottages Limited | Hospitality | 2021 |
| Educational Exports Ltd | Information & communication | 2022 |
| Edwardian Way Ltd | Health & social care | 2018 |
| Edwards Ortho Ltd | Professional & scientific | 2014 |
| EGH Properties Ltd | Construction | 2017 |
| Eiddo 2020 Ltd | Real estate | 2020 |
| Elemental Rentals Limited | Real estate | 2024 |
| Eleri Jones Ltd | Professional & scientific | 2021 |
| Elevate Mobility Ltd | Wholesale & retail | 2019 |
| Elite Pipeline Services Ltd | Water & waste | 2017 |
| Elizabeth-Anne Children`S Wear Limited | Wholesale & retail | 2004 |
| Elliot Bespoke Holdings Ltd | Financial services | 2025 |
| Ellis Hunt Ltd | Information & communication | 2025 |
| Emma Hall Designs Ltd | Extraterritorial | 2016 |
| Employment With AMY Limited | Professional & scientific | 2025 |
| England Environmental (Northern) Limited | Administrative & support | 1995 |
| Englands Limited | Real estate | 1905 |
| Enzo (Cleaning Products) Limited | Manufacturing | 1995 |
| EPS Steels (UK) Limited | Wholesale & retail | 2005 |
| Equi-Nine UK Limited | Other services | 2024 |
| ERC Assets Ltd | Real estate | 2025 |
| Eryr Properties Ltd | Construction | 2021 |
| ESA Treecare Limited | Agriculture & fishing | 2003 |
| Evelyn Crescent Limited | Hospitality | 1970 |
| Evelyn Terrace Limited | Real estate | 1994 |
| Event Catering Limited | Hospitality | 2003 |
| Eventdetail Limited | Hospitality | 1994 |
| EVS & EVS Properties Limited | Real estate | 2017 |
| EWJ Safeguarding & Social Work Consultancy Ltd | Professional & scientific | 2023 |
| Exedab Ltd | Information & communication | 2020 |
| Experience Professional Development Ltd | Professional & scientific | 2024 |
| Expert Authority Enterprises Ltd. | Professional & scientific | 2017 |
| F.E.White Advisory Limited | Professional & scientific | 2020 |
| Falco Financial Planning Ltd | Financial services | 2018 |