| Astrocare Maintenance Ltd | Construction | 2021 |
| Astute Solutions Ltd | Professional & scientific | 2025 |
| ASW Compliance Consultancy Limited | Professional & scientific | 2021 |
| ASW Financial Management Ltd | Financial services | 2016 |
| AT the Waters Edge Ltd | Information & communication | 2013 |
| ATA Mode Ltd | Wholesale & retail | 2023 |
| Atalanti SIX Limited | Administrative & support | 2005 |
| ATC Nationwide Limited | Administrative & support | 2018 |
| ATD Improvements Ltd | Construction | 2025 |
| ATG Chauffeuring Limited | Administrative & support | 2025 |
| Athena REI Ltd | Financial services | 2021 |
| Atkda Ltd | Arts & recreation | 2022 |
| Atkinson & Lockyer Limited | Financial services | 2023 |
| Atlantic House Developments Ltd | Construction | 2016 |
| Atlantic House Management Ltd | Extraterritorial | 2016 |
| Atlantic Nurseries (Wholesale) Limited | Wholesale & retail | 1987 |
| Atlantic Risk Business Solutions Limited | Professional & scientific | 2025 |
| Atlantis (B'Ham) Limited | Administrative & support | 2012 |
| Atlantis Castle Bromwich Limited | Hospitality | 2015 |
| Atlantis Quinton Limited | Hospitality | 2016 |
| Atlantis WM Limited | Hospitality | 2018 |
| Atlas Contractor Services Ltd | Construction | 2024 |
| Atlas Healthcare Ltd | Health & social care | 2025 |
| Atlas Midlands Holdings Limited | Real estate | 2014 |
| Atlas Pain Relief Ltd | Health & social care | 2020 |
| Atluts Limited | Extraterritorial | 2022 |
| Atmosphere Solutions Ltd | Financial services | 2015 |
| ATN Corporation Ltd | Real estate | 2022 |
| Atos JIU Jitsu UK Ltd | Arts & recreation | 2019 |
| Atos UK JIU Jitsu Associates Ltd | Wholesale & retail | 2024 |
| ATR Properties Limited | Other services | 2007 |
| Atrg Limited | Professional & scientific | 2006 |
| Atrina Group Limited | Wholesale & retail | 2018 |
| Att-Mp Limited | Information & communication | 2025 |
| Attar Mist Ltd | Wholesale & retail | 2013 |
| Attention to Beauty Limited | Other services | 2018 |
| Atwal and Hayer Ltd | Real estate | 2022 |
| AU Invest Limited | Real estate | 2025 |
| Audio Visual One Ltd | Wholesale & retail | 2019 |
| Audioviz Rent Ltd | Administrative & support | 2025 |
| Augment Design Ltd | Professional & scientific | 2019 |
| Augmentx Ltd | Information & communication | 2024 |
| Aujla Estates (Birmingham) Ltd | Real estate | 2026 |
| Auklogis UK Ltd | Transport & logistics | 2026 |
| Aura Aldridge Limited | Hospitality | 2019 |
| Aura Hair and Skin Ltd | Other services | 2003 |
| Auraya Collections Limited | Wholesale & retail | 2026 |
| Aurora Bay Limited | Real estate | 2023 |
| Aurum Gallery Limited | Wholesale & retail | 2017 |
| Aurum Supply Ltd | Wholesale & retail | 2025 |
| Auto Body Care Birmingham Ltd | Wholesale & retail | 2026 |
| Autobase Valet Services Ltd | Administrative & support | 2007 |
| Autohaus Select Group Ltd | Wholesale & retail | 2025 |
| Autopilot AI Ltd | Information & communication | 2025 |
| Autostock Ltd | Wholesale & retail | 2026 |
| Autotone Limited | Information & communication | 2025 |
| Autumn Tree Investments Ltd | Real estate | 2024 |
| AV14 Limited | Real estate | 2020 |
| AV2 Ltd | Hospitality | 2024 |
| AVA Sturridge-Packer Education Solutions Limited | Education | 2018 |
| Avaeventsplanning Limited | Hospitality | 2023 |
| Avani Homes Limited | Real estate | 2022 |
| Avani Properties Ltd | Real estate | 2020 |
| AVE Maria Care Ltd | Health & social care | 2014 |
| Avenden Limited | Real estate | 2015 |
| Aventador Security & Executive Chauffeuring Ltd Ltd | Administrative & support | 2014 |
| Avery Language Service Limited | Professional & scientific | 2013 |
| AVG-33 Limited | Financial services | 2026 |
| Avherlimz Ltd | Transport & logistics | 2021 |
| Avid Concepts Limited | Construction | 2021 |
| Avid Installation Solutions Limited | Professional & scientific | 2008 |
| Avion Solutions Ltd | Information & communication | 2016 |
| Avita (UK) Ltd | Manufacturing | 2013 |
| AVM Construction Services Ltd | Construction | 2021 |
| AVS Consultancy PVT Ltd | Information & communication | 2016 |
| Avukcom Ltd | Wholesale & retail | 2012 |
| AVW Property Ltd | Real estate | 2018 |
| Avytech Consulting Limited | Information & communication | 2017 |
| AW Dermatology Ltd | Health & social care | 2003 |
| Awan Wholesale Ltd | Wholesale & retail | 2024 |
| AWB TM Limited | Construction | 2024 |
| Awea Properties Limited | Real estate | 2021 |
| Awinco Limited | Real estate | 2023 |
| AWL Asset & Investment Ltd | Financial services | 2021 |
| AWS Commercial Window Systems Limited | Construction | 1990 |
| AWS Turner Fain Limited | Manufacturing | 1982 |
| Awsm Solutions Limited | Information & communication | 2025 |
| AX09 Autos Ltd | Manufacturing | 2025 |
| AXB Coaching Ltd | Health & social care | 2023 |
| Axel Properties Midlands Limited | Real estate | 2024 |
| Axel Transport Ltd | Transport & logistics | 2022 |
| Axen Solutions Ltd | Administrative & support | 2025 |
| Axia Watch Co Limited | Wholesale & retail | 2019 |
| AXIO1 Limited | Real estate | 2023 |
| AXIO2 Limited | Real estate | 2023 |
| Axiom Building Solutions Group Ltd | Financial services | 2026 |
| Axiom Building Solutions Limited | Water & waste | 2010 |
| Axiom Energy & Utilities Ltd | Professional & scientific | 2015 |
| AY Aspire Tutors LLP | | 2025 |
| AYM Personal Services Limited | Health & social care | 2023 |