| Anthony Webb & Sons Properties Ltd | Real estate | 2021 |
| Anujaan Cannock Ltd | Hospitality | 2025 |
| Anylec Limited | Construction | 2015 |
| AP & PJ Properties Limited | Real estate | 2020 |
| AP Construction&Groundwork Ltd | Construction | 2020 |
| APC Holdco Limited | Financial services | 2024 |
| APC Overnight Limited | Transport & logistics | 1998 |
| Apex 28 Asset Management Limited | Real estate | 2021 |
| Apex Computer & Telephone Services Limited | Manufacturing | 2003 |
| Apex Construction Management LLP | | 2020 |
| Apex Electrical & Electronic Services Ltd. | Manufacturing | 1995 |
| Apex Luxury Limited | Wholesale & retail | 2015 |
| Apex Roofing (Staffordshire) Ltd | Construction | 2024 |
| APG Plumbing and Heating Services Limited | Construction | 2014 |
| Apol Installations Limited | Professional & scientific | 2021 |
| Apollo Freight (U K) Limited | Transport & logistics | 2016 |
| Apollo Housewares Limited | Wholesale & retail | 1987 |
| Appcoast Limited | Information & communication | 2009 |
| Appetite Foods Ltd | Wholesale & retail | 2024 |
| Application Technology Limited | Other services | 2019 |
| Applied Fluid Power Limited | Wholesale & retail | 1998 |
| Approved Roofing Services Ltd | Construction | 2025 |
| Apress Holdings Ltd | Professional & scientific | 2023 |
| Apress Investments Ltd | Professional & scientific | 2023 |
| APS Landscapes Limited | Administrative & support | 2026 |
| APW Glazing Limited | Construction | 2002 |
| Apxdevuk Ltd | Wholesale & retail | 2024 |
| AQS (Midlands) Ltd | Professional & scientific | 2009 |
| Aquarius Accommodation Ltd | Hospitality | 2024 |
| Aquarius Fire Sprinklers Ltd | Construction | 2018 |
| Aquatic Services Limited | Administrative & support | 2025 |
| AR Carpentry Ltd | Construction | 2022 |
| AR International Holdings Ltd | Wholesale & retail | 2018 |
| ARC Mancaves GB Limited | Construction | 2016 |
| Archa Consulting Limited | Information & communication | 2018 |
| Archer's Groundwork Services Limited | Construction | 2014 |
| Arden Commercial Finance Ltd | Financial services | 2009 |
| Areum HAN Limited | Arts & recreation | 2025 |
| Argent Industrial Investments UK Ltd | Real estate | 2024 |
| Argent Industrial UK Ltd | Financial services | 2020 |
| ARH (Care) Limited | Health & social care | 2024 |
| ARK Building Services Ltd | Construction | 2024 |
| Arkrite Fencing Manufacturers Limited | Manufacturing | 1973 |
| Arlo Drive Management Company Ltd | Real estate | 2024 |
| Armchair Adviser Ltd | Financial services | 2024 |
| Armchair Mortgages Limited | Financial services | 2001 |
| Armishaw Contractors Limited | Construction | 2022 |
| Armourlec Limited | Construction | 2021 |
| Arnie Enterprises Ltd | Hospitality | 2020 |
| ARO Accountancy Limited | Professional & scientific | 2021 |
| ARQ Financial Planning Ltd | Financial services | 2026 |
| Arragon Court Management Limited | Households | 2012 |
| Arrowgas Limited | Construction | 2003 |
| Art Design Solutions Limited | Administrative & support | 2004 |
| Art One (Walsall) Limited | Real estate | 2010 |
| Artech Services Limited | Manufacturing | 1997 |
| Artemis Direct Ltd | Wholesale & retail | 2022 |
| Arun Services Ltd | Wholesale & retail | 2016 |
| Arvan Limited | Real estate | 1996 |
| AS Ventures Limited | Professional & scientific | 2004 |
| ASA Studio Ltd | Information & communication | 2017 |
| Asanka Group Limited | Information & communication | 2022 |
| Ascension Coaching Ltd | Education | 2024 |
| Ascot Industrial Supplies Limited | Wholesale & retail | 2014 |
| ASH Stitch in Time Limited | Manufacturing | 2024 |
| Ashgreen Group Limited | Real estate | 2017 |
| Ashleigh Developments Limited | Construction | 2015 |
| Ashleigh House (Wolverhampton) Limited | Health & social care | 2012 |
| Ashley Rich Limited | Information & communication | 2016 |
| Ashtree Trading Activities Ltd | Other services | 2019 |
| Ashware Electrical Ltd | Construction | 2023 |
| Ashwoodch Ltd | Health & social care | 2024 |
| ASL Plastering Ltd | Construction | 2021 |
| Asps Recycling Limited | Water & waste | 2000 |
| Assistly International Limited | Wholesale & retail | 2025 |
| Association of Worship & Venue Technicians CIC | Education | 2024 |
| Assurin IT Limited | Information & communication | 2012 |
| Aston Bentley Interiors Limited | Wholesale & retail | 1978 |
| Astownding Design Ltd | Professional & scientific | 2015 |
| ATC Carpentry Ltd | Construction | 2024 |
| ATC Drivetrain UK Ltd | Manufacturing | 1969 |
| ATG (MSP) Ltd | Information & communication | 2025 |
| ATG Property Developments Limited | Other services | 2012 |
| Athena Leasing Limited | Administrative & support | 2010 |
| Atlas Commercial Cleaning Ltd | Administrative & support | 2026 |
| Atlas One Limited | Administrative & support | 2024 |
| ATM Skip Hire Ltd | Water & waste | 2019 |
| Atom Medical Corporation UK Limited | Administrative & support | 2020 |
| Atticus Energy Ltd | Mining & quarrying | 2014 |
| Attwal Investments Limited | Wholesale & retail | 2015 |
| Audomation Software Limited | Information & communication | 2013 |
| Auger Holdings Ltd | Financial services | 2022 |
| Aura Residential Care Limited | Health & social care | 2023 |
| Aura Support & Education Limited | Education | 2024 |
| Austin Harrison Developments Ltd | Construction | 2024 |
| Austin Harrison Investments Ltd | Real estate | 2024 |
| Autium Limited | Administrative & support | 2016 |
| Automotive Delivery Company Limited | Administrative & support | 2011 |
| Automove Limited | Transport & logistics | 2020 |
| Avanah Health Ltd | Health & social care | 2025 |