| Alphacoast Limited | Wholesale & retail | 2015 |
| Alphamstone Prestige Ltd | Transport & logistics | 2014 |
| Alphaprotech Ltd | Information & communication | 2022 |
| Alphasense Limited | Manufacturing | 1996 |
| Alphaweld&Fab Ltd | Construction | 2010 |
| Alphax Group Ltd | Information & communication | 2024 |
| Alpica Ltd | Information & communication | 2024 |
| ALR Homes Limited | Real estate | 2025 |
| Alrayes Limited | Information & communication | 2008 |
| Alrodia London Limited | Wholesale & retail | 2023 |
| Alsamdk Limited | Information & communication | 2019 |
| Alsawah for Trade Ltd | Wholesale & retail | 2025 |
| Alstar Asset Management Limited | Financial services | 2019 |
| Alstis Ltd | Transport & logistics | 2025 |
| ALT Group Ltd | Information & communication | 2018 |
| Alt-H Limited | Professional & scientific | 2015 |
| Alta Property Group Ltd | Households | 2020 |
| Altaf Patel (Civil Engineering Division) Limited | Professional & scientific | 2016 |
| Alterius Systems Limited | Information & communication | 2011 |
| Alternativa Memories Ltd | Transport & logistics | 2015 |
| Alternative Action Group Community Interest Company | Health & social care | 2024 |
| Alternative Energy Developments PLC | Wholesale & retail | 2010 |
| Alternative Voices Theatre Company CIC | Health & social care | 2025 |
| Alterno Wealth Limited | Financial services | 2015 |
| Althea Direct Cares Ltd | Health & social care | 2025 |
| Althias Ventures Limited | Real estate | 2018 |
| Alti Expert Ltd | Construction | 2017 |
| Altinova Solutions Ltd | Wholesale & retail | 2025 |
| Altior Group Ltd | Professional & scientific | 2025 |
| Altiora Enterprises Ltd | Wholesale & retail | 2025 |
| Altitude Estates Limited | Real estate | 2021 |
| Alto Audiology Ltd | Wholesale & retail | 2025 |
| Alto Verde Holdings Limited | Financial services | 2019 |
| Alto Verde Limited | Professional & scientific | 2018 |
| Altosphere Ltd | Information & communication | 2019 |
| Altrincham Perfection Ltd | Transport & logistics | 2015 |
| Altus Health Ltd | Professional & scientific | 2015 |
| Altus Installations Limited | Construction | 2018 |
| Aluflex Ltd | Manufacturing | 2023 |
| Alufold Window Systems Ltd | Manufacturing | 2005 |
| Aluminium Pontoons Ltd | Manufacturing | 2021 |
| Alutur Heritage Doors Limited | Extraterritorial | 2022 |
| Aluxclean Ltd | Administrative & support | 2023 |
| Alva CONSTRUCT1ON Limited | Construction | 2021 |
| Alva Life Ltd | Construction | 2022 |
| Alverty Odala Ltd | Health & social care | 2016 |
| Alvi Investment Ltd | Real estate | 2025 |
| Alvin Davies Limited | Wholesale & retail | 2009 |
| Alvix Group Ltd | Wholesale & retail | 2025 |
| Alvs Holdings Ltd | Financial services | 2024 |
| Alvs Opticare Ltd | Health & social care | 2024 |
| Alwalton Stores Ltd | Wholesale & retail | 2021 |
| Alwanetworks Ltd | Information & communication | 2026 |
| Always 21 Ltd | Other services | 2019 |
| Always Here for YOU Ltd | Health & social care | 2018 |
| Always Present Ltd | Wholesale & retail | 2016 |
| Always Traffic Management Ltd | Construction | 2026 |
| Alwaystrusted Limited | Wholesale & retail | 2016 |
| Alweather Limited | Health & social care | 2019 |
| Alwyn Norton Ltd | Wholesale & retail | 2025 |
| Alxr Limited | Wholesale & retail | 2019 |
| ALY & Co Accountants Ltd | Professional & scientific | 2022 |
| ALY SAJ Investments Ltd | Real estate | 2025 |
| ALY84 Spedition Ltd | Transport & logistics | 2020 |
| Alya Estates Ltd | Real estate | 2026 |
| Alyan Security and Services Limited | Administrative & support | 2024 |
| Alyan Services Limited | Administrative & support | 2023 |
| Alzain Kitchen Ltd | Hospitality | 2024 |
| Alzas Group Ltd | Wholesale & retail | 2022 |
| Alzayn Holdings Limited | Professional & scientific | 2025 |
| Alzn Ltd | Real estate | 2024 |
| AM & JF Limited | Wholesale & retail | 1988 |
| AM Commercial Properties Limited | Real estate | 2018 |
| AM EV & Electrical Ltd | Construction | 2026 |
| AM Halal Meats @Wholesales Ltd | Wholesale & retail | 2017 |
| AM Haulage Contractors Ltd | Transport & logistics | 2025 |
| AM Homes (Leicester) Limited | Construction | 2022 |
| AM Insights Ltd | Information & communication | 2019 |
| AM Kitchens Ltd | Manufacturing | 2016 |
| AM Logistics & Transportation Ltd | Transport & logistics | 2025 |
| AM Plumbing & Heating (Leicester) Limited | Construction | 2012 |
| AM Private Care Ltd | Health & social care | 2022 |
| AM Residential Properties Limited | Real estate | 2018 |
| AM Skin Products Limited | Other services | 2026 |
| AM Trading Group Limited | Wholesale & retail | 2025 |
| AM Trucks Ltd | Wholesale & retail | 2015 |
| Am:Ai Technologies Limited | Manufacturing | 2024 |
| AMA CASH4CLOTHES Ltd | Wholesale & retail | 2025 |
| AMA Styles Limited | Wholesale & retail | 2024 |
| Amaan Packaging Ltd | Wholesale & retail | 2026 |
| Amaan Pound Shop and Groceries Limited | Wholesale & retail | 2014 |
| Amaanah Europe Ltd | Hospitality | 2019 |
| Amabis (UK) Limited | Administrative & support | 2002 |
| Amafhh Auto Parts Ltd | Wholesale & retail | 2025 |
| Amafhh Care Homes Limited | Health & social care | 2008 |
| Amafhh Consultancy Limited | Information & communication | 2015 |
| Amafhh Foods Limited | Hospitality | 2021 |
| Amafhh Group Limited | Manufacturing | 2019 |
| Amafhh Properties Limited | Real estate | 2017 |
| Amafhh Security Limited | Administrative & support | 2007 |