| A-List Nutrition Ltd | Wholesale & retail | 2016 |
| A-Maison UK Ltd | Wholesale & retail | 2025 |
| A-Ok Media House Ltd | Information & communication | 2016 |
| A-One Parking Ltd | Transport & logistics | 2025 |
| A-Plus Enterprise Co., Ltd | Extraterritorial | 2016 |
| A-Z Barbers Cardiff Ltd | Other services | 2021 |
| A-Z Cleaning and Moving Ltd | Transport & logistics | 2026 |
| A-Z Diagnostics Ltd | Health & social care | 2023 |
| A-Z Home Makeovers Ltd | Construction | 2024 |
| A-Z Lets Ltd | Real estate | 2024 |
| A-Z Manufacturing Ltd | Manufacturing | 2022 |
| A-Z Safety Ltd | Public administration | 2022 |
| A. Berridge & Company Limited | Professional & scientific | 1997 |
| A. Gaitonde Limited | Health & social care | 2007 |
| A. R. Trading HK Limited | Financial services | 2024 |
| A.A. Care Services Ltd | Health & social care | 2019 |
| A.B Morrison Limited | Water & waste | 2018 |
| A.B.C Taxis (EA) Ltd | Transport & logistics | 2022 |
| A.C. Fixes Limited | Construction | 2025 |
| A.C. Motorsport Ltd | Arts & recreation | 2024 |
| A.Classs Properties & General Enterprise Ltd | Real estate | 2025 |
| A.D Professional Painters Ltd | Construction | 2019 |
| A.D.B Trans Ltd | Transport & logistics | 2013 |
| A.D.S Removals Ltd | Transport & logistics | 2019 |
| A.E.M Property Ltd | Hospitality | 2024 |
| A.Fryer & Sons Limited | Professional & scientific | 1946 |
| A.G. Meek Limited | Wholesale & retail | 1955 |
| A.G.Leer Limited | Construction | 1963 |
| A.G.Wade Ltd | Health & social care | 2003 |
| A.Gakou Ltd | Professional & scientific | 2019 |
| A.Gill Holdings Limited | Real estate | 2015 |
| A.H.S. Construction Limited | Construction | 2009 |
| A.I.S. Physiotherapy Services Limited | Health & social care | 2002 |
| A.J. and G Properties Limited | Real estate | 2018 |
| A.J. Freeman & Sons Limited | | 1990 |
| A.J.M Property Developments Improvements Ltd | Construction | 2025 |
| A.K.M. Professional Services Limited | Professional & scientific | 2013 |
| A.M Design Studio Limited | Professional & scientific | 2025 |
| A.M Properties and Developers Ltd | Real estate | 2021 |
| A.M.E. Outsource Specialists 1 Limited | Professional & scientific | 2025 |
| A.M.E. Outsource Specialists 2 Limited | Professional & scientific | 2025 |
| A.M.E. Outsource Specialists 3 Limited | Professional & scientific | 2025 |
| A.M.E. Outsource Specialists 4 Limited | Professional & scientific | 2025 |
| A.M.E. Outsource Specialists 5 Limited | Professional & scientific | 2025 |
| A.M.E. Outsource Specialists 6 Limited | Professional & scientific | 2025 |
| A.M.E. Outsource Specialists Limited | Professional & scientific | 2025 |
| A.M.I.A. Group International Ltd. | Information & communication | 2020 |
| A.M.L. Leisure Limited | Hospitality | 2007 |
| A.M.L. Scaffolding (Holdings) Limited | Financial services | 2016 |
| A.M.R. Incorporated Limited | Construction | 2018 |
| A.Mclay and Company Limited | Administrative & support | 1902 |
| A.N.T. Estates Limited | Administrative & support | 2014 |
| A.P. Baker & Co. Limited | Professional & scientific | 2014 |
| A.P.Kane Limited | Construction | 2007 |
| A.P.Properties (Cardiff) Limited | Administrative & support | 1972 |
| A.R.B. Electrical Ltd | Construction | 1996 |
| A.R.D.H. Investments Ltd | Financial services | 2019 |
| A.R.M. (Wales) Limited | Manufacturing | 2006 |
| A.S Mortgage Broker Ltd | Financial services | 2019 |
| A.S. Gulf Services (U.K.) Limited | Wholesale & retail | 1983 |
| A.S.K Recovery Limited | Wholesale & retail | 2011 |
| A.S.Ockwell Limited | Wholesale & retail | 1955 |
| A.T Ecom Ltd | Wholesale & retail | 2024 |
| A.W.Dallas Financial Services Limited | Financial services | 2008 |
| A1 Cars Rental Services Ltd | Transport & logistics | 2018 |
| A1 Cuts Limited | Construction | 2017 |
| A1 Fruit and VEG Ltd | Wholesale & retail | 2019 |
| A1 Haulage Services Ltd | Transport & logistics | 2017 |
| A1 Hinton Home Inspections Limited | Professional & scientific | 2007 |
| A1 Media Productions UK Ltd | Manufacturing | 2025 |
| A1 Merchant Ltd | Wholesale & retail | 2018 |
| A1 Motorcare Limited | Wholesale & retail | 1997 |
| A1 Plumbing Decoration Ltd | Construction | 2026 |
| A1 Property (Cardiff) Ltd | Real estate | 2017 |
| A1 Scaffolding Cardiff Ltd | Construction | 2020 |
| A1 Scapes Ltd | Administrative & support | 2025 |
| A1 Speedy Recoveries Limited | Wholesale & retail | 2020 |
| A1 Survey Limited | Administrative & support | 2003 |
| A1 Surveying & Engineering Services Ltd. | Administrative & support | 2007 |
| A14 Films Ltd | Information & communication | 2018 |
| A2 Everything Ltd | Wholesale & retail | 2019 |
| A2 Investments Limited | Real estate | 2003 |
| A2B Equipements Ltd | Other services | 2012 |
| A2B Property Limited | Real estate | 2017 |
| A2B Recruitment Personnel Ltd | Administrative & support | 2024 |
| A2B-AUTOCARE Limited | Extraterritorial | 2022 |
| A2B-INVESTMENT Portfolio Limited | Real estate | 2024 |
| A2B-M Limited | Transport & logistics | 2023 |
| A2B-T Limited | Transport & logistics | 2023 |
| A2B-TRAVELLINK Limited | Transport & logistics | 2017 |
| A2BSCAFFOLDINGSW Ltd | Construction | 2024 |
| A2G N Properties Limited | Construction | 2019 |
| A2HER Estates Ltd | Real estate | 2016 |
| A2Z Food Safety Limited | Administrative & support | 2014 |
| A2Z Landscaping Ltd | Administrative & support | 2025 |
| A2Z Luxury Construction Ltd | Construction | 2025 |
| A2Z Smile Ltd | Education | 2022 |
| A2ZCARHIRE Limited | Administrative & support | 2018 |
| A3I Limited | Manufacturing | 2017 |
| A3M Partnerships Ltd | Real estate | 2024 |