| 18-20 Market Street Tredegar Management Company Ltd | Administrative & support | 2009 |
| 1ST Choice Flooring C&J Ltd | Construction | 2020 |
| 247 Autocentre Ltd | Wholesale & retail | 2025 |
| 247 Recovery Services Ltd | Wholesale & retail | 2023 |
| 247AUTOMOTIVEGROUP Ltd | Financial services | 2025 |
| 3 Celts Limited | Construction | 2019 |
| 360 Photo Ltd | Other services | 2016 |
| 3TR Limited | Hospitality | 2024 |
| 3VW Limited | Wholesale & retail | 2026 |
| 7 Day Laundry Ltd | Other services | 2019 |
| 9 ST John's Road Residents Limited | Hospitality | 2002 |
| A & G Haulage Limited | Transport & logistics | 2016 |
| A L Robins Partitioning & Suspended Ceiling Ltd | Construction | 2024 |
| A Roche Services Limited | Construction | 2018 |
| A Sullivan Limited | Manufacturing | 2012 |
| A Touch of Glass and Glazing Limited | Construction | 2022 |
| A V Peterson & Sons Limited | Extraterritorial | 2001 |
| A Welsh Connection (Homewares) Limited | Wholesale & retail | 2015 |
| A&E Drylining Limited | Construction | 2025 |
| A-Tek Group Limited | Construction | 2018 |
| A.R. Optical Limited | Wholesale & retail | 2008 |
| A.S. Thouhgtful Care Limited | Health & social care | 2013 |
| A2Z Supplies Limited | Wholesale & retail | 2024 |
| A3 Anchorstone Properties Ltd | Real estate | 2025 |
| ABL Training and Consultancy Ltd | Education | 2012 |
| Able Radio | Education | 2008 |
| ACCELUR8 Ltd | Information & communication | 2024 |
| Action Electrical Contractors Limited | Energy | 2010 |
| AD Valeting & Pressure Washer Services Ltd | Wholesale & retail | 2019 |
| Adam Lewis First in Mortgages Ltd | Financial services | 2025 |
| ADOPT365 Ltd | Professional & scientific | 2026 |
| Adtech CNC Europe Ltd | Wholesale & retail | 2012 |
| Advance Home Improvements Ltd | Construction | 2018 |
| Advanta Group Limited | Manufacturing | 2000 |
| Adventure Bike Tours Wales Ltd | Administrative & support | 2025 |
| Afil Ltd | Manufacturing | 1988 |
| Afon Energy Limited | Energy | 2011 |
| AFW Holdings Ltd | Real estate | 2021 |
| AGC Associates Limited | Professional & scientific | 2007 |
| Agnes R Limited | Hospitality | 2025 |
| Aice Consultants Ltd | Professional & scientific | 2010 |
| Aimaites Ltd | Information & communication | 2023 |
| Air Midlands Limited | Transport & logistics | 2024 |
| Airpure Solutions Ltd | Construction | 2025 |
| Airquee Limited | Manufacturing | 1995 |
| Airsolve Limited | Manufacturing | 2013 |
| AJ. MB. KG Properties Limited | Real estate | 2023 |
| Alacrity Solutions Group Limited | Professional & scientific | 2024 |
| Albani's Cars Ltd | Wholesale & retail | 2024 |
| Alexander Financial Consultancy Ltd | Professional & scientific | 2019 |
| Alexktaylor Consulting Ltd | Professional & scientific | 2023 |
| ALI and Sons (Cwmbran) Properties Ltd | Real estate | 2023 |
| ALL Clad Industrial Roofing Supplies Ltd | Wholesale & retail | 2018 |
| Alpha B C Services Ltd | Construction | 2021 |
| Alphabettz Embroidery Ltd | Manufacturing | 2009 |
| ALR Network Solutions Ltd | Manufacturing | 2026 |
| Alrl Property Management Limited | Real estate | 2024 |
| Altech Software Limited | Information & communication | 2005 |
| Always Cooking Ltd | Hospitality | 2020 |
| AMA Aesthetic Healthcare Ltd | Health & social care | 2022 |
| Ameltio Performance Ltd | Arts & recreation | 2024 |
| Amotio Health Limited | Manufacturing | 2025 |
| AMS Specialist Cars Ltd | Wholesale & retail | 2025 |
| Analogue & Micro Limited | Professional & scientific | 1996 |
| Andmorg Limited | Wholesale & retail | 2022 |
| Andy Powell Limited | Construction | 2007 |
| Apex Home Solutions Limited | Construction | 2006 |
| Apex LV Ltd | Construction | 2026 |
| Apex Turtle Studios Ltd | Information & communication | 2026 |
| Apidae Workforce Consulting Ltd | Extraterritorial | 2021 |
| APL Couriers Ltd | Transport & logistics | 2021 |
| Apollo Spaces Ltd | Real estate | 2020 |
| Aquameshproperties Limited | Real estate | 2025 |
| AR Food Services Limited | Hospitality | 2018 |
| AR Mortgage Solutions Ltd | Financial services | 2019 |
| ARB Communication Ltd | Information & communication | 2024 |
| Archelon Ltd | Manufacturing | 2025 |
| Arcs Engineering Limited | Professional & scientific | 2025 |
| Arda Consulting Limited | Professional & scientific | 2017 |
| Arion Music UK Limited | Administrative & support | 2011 |
| ARK Fencing and Garden Services Ltd | Administrative & support | 2023 |
| Arkwall Limited | Construction | 1990 |
| Arthur Peake (Memorials) Limited | Other services | 2008 |
| Arvin International (UK) Limited | Administrative & support | 1988 |
| Arvin Motion Control Limited | Other services | 1999 |
| Arvinmeritor A&Et Limited | Administrative & support | 1993 |
| Arvinmeritor Light Vehicle Systems (UK) Limited | Manufacturing | 1927 |
| Arvinmeritor Limited | Administrative & support | 1972 |
| Asaga Express Ltd | Hospitality | 2024 |
| Asaga Legend Limited | Hospitality | 2020 |
| Asaga Noodle Bar Limited | Manufacturing | 2019 |
| Asbava Limited | Administrative & support | 2022 |
| Ascher & Void Ltd | Wholesale & retail | 2025 |
| Ashleigh Court Associates Limited | Professional & scientific | 2015 |
| Asia Foods Cwmbran Ltd | Administrative & support | 2018 |
| ASL Holdings Limited | Manufacturing | 2002 |
| ASP Creative Crafts Ltd | Wholesale & retail | 2025 |
| Aspire Business Solutions Limited | Public administration | 2024 |
| Aspire Project Partners Ltd | Professional & scientific | 2025 |
| Asset Ventilation Solutions Ltd | Construction | 2024 |