| Aero Gearbox International Limited | Professional & scientific | 2015 |
| Aerointel Ltd | Manufacturing | 2025 |
| Aeromech Engineering Ltd | Professional & scientific | 2020 |
| Aerotonomy Ltd | Professional & scientific | 2021 |
| Aerox Ltd | Wholesale & retail | 2023 |
| Aertex Limited | Wholesale & retail | 1998 |
| Aesthedent Ltd | Health & social care | 2023 |
| Aesthetic Atelier by Paula Tanda Ltd | Health & social care | 2024 |
| Aesthetically Beautified Limited | Other services | 2021 |
| Aevim Limited | Professional & scientific | 2025 |
| Affordable Deals Ltd | Wholesale & retail | 2023 |
| Afiniti Europe Technologies Limited | Information & communication | 2013 |
| Afiyaafrica UK Ltd | Health & social care | 2026 |
| Afrafan Nominee Limited | Administrative & support | 2017 |
| Africa Dome Village Ltd | Hospitality | 2025 |
| Africa International Chamber Ltd | Other services | 2024 |
| Africana Media Enterprises CIC | Information & communication | 2024 |
| Afriharmony Productions Ltd | Hospitality | 2024 |
| Afrik Wears Ltd | Professional & scientific | 2025 |
| Afro Rayol Ltd | Wholesale & retail | 2025 |
| AFZ Accountancy Limited | Professional & scientific | 2013 |
| AG London Properties Limited | Real estate | 2017 |
| AG Plumbing Solutions Limited | Construction | 2025 |
| Against the Odds Movement C.I.C. | Education | 2025 |
| Agam Property Ltd | Real estate | 2022 |
| Agile Innovation Solutions Limited | Information & communication | 2019 |
| Agilix Technologies Ltd | Information & communication | 2024 |
| AGK Corp Ltd | Professional & scientific | 2024 |
| AGS Salford Limited | Hospitality | 2025 |
| Aguda North West | Professional & scientific | 2005 |
| Agudas Hapoalim Supplier Limited | Hospitality | 2020 |
| AH & E Investments Ltd | Real estate | 2014 |
| Ahmed Halls Properties Ltd | Real estate | 2020 |
| Ahmed Surgical Ltd | Health & social care | 2026 |
| Ahmed Ventures Limited | Wholesale & retail | 2024 |
| Ahmm Allusions Limited | Hospitality | 2024 |
| Ahuja Brothers Rental Ltd | Real estate | 2023 |
| Ahura Healthcare Ltd | Manufacturing | 2023 |
| AI Fitness Solutions Ltd | Information & communication | 2026 |
| AI Formations Limited | Other services | 2018 |
| AI Quintessential Limited | Education | 2020 |
| Aiamz Trimming Studio Ltd | Wholesale & retail | 2025 |
| AIB Electrical Ltd | Other services | 2016 |
| Aila Property Ltd | Real estate | 2018 |
| AIM Global Group Limited | Manufacturing | 2018 |
| AIM Habonim | Education | 2010 |
| Aimee Watson Ltd | Health & social care | 2018 |
| Aimvpr Ltd | Wholesale & retail | 2020 |
| AIN FS Ltd | Professional & scientific | 2025 |
| Ainsdale Distribution Ltd | Extraterritorial | 2014 |
| Ainsdale Estates Ltd | Real estate | 2020 |
| Ainsworth Nominees 2 Ltd | Extraterritorial | 2019 |
| Ainsworth Nominees Ltd | Extraterritorial | 2017 |
| Air Dryer Technology Limited | Manufacturing | 2005 |
| Air Handlers (Northern) Limited | Manufacturing | 1992 |
| Air Handling Components Limited | Manufacturing | 1998 |
| Airbles Assets (2) Limited | Extraterritorial | 2015 |
| Airbles Assets Limited | Extraterritorial | 2015 |
| Airfixit Ltd | Construction | 2019 |
| Airlyte Innovations Ltd | Wholesale & retail | 2025 |
| Airswift Global Limited | Financial services | 2021 |
| Airswift Holdings Limited | Administrative & support | 2015 |
| Airswift Technical Services Limited | Administrative & support | 2003 |
| Airswift Trustees Limited | Financial services | 2020 |
| Airtix Ltd | Construction | 2023 |
| Aisone Ltd | Construction | 2023 |
| Aitu and Sons Limited | Transport & logistics | 2022 |
| AIX Construction Ltd | Construction | 2025 |
| AJ Property (Manchester) Ltd | Construction | 2023 |
| AJ Property MCR Limited | Real estate | 2025 |
| Aj's Griller Ltd | Hospitality | 2019 |
| AJB Housing Services Ltd | Real estate | 2024 |
| AJB Properties Ltd | Real estate | 2024 |
| Ajem Holdings Ltd | Financial services | 2024 |
| Ajiwa Limited | Manufacturing | 2025 |
| AK Aras Barber Limited | Other services | 2025 |
| AK Gold Transport Ltd | Transport & logistics | 2024 |
| AK LCD Repair Ltd | Manufacturing | 2024 |
| Akav Holdings Ltd | Real estate | 2023 |
| AKB Ventures Limited | Wholesale & retail | 2020 |
| Akin-Akaad Limited | Information & communication | 2014 |
| Akina Investments Limited | Financial services | 2025 |
| Akiv Ltd | Hospitality | 2024 |
| AKJ Care Ltd | Health & social care | 2013 |
| Akrobatt Limited | Information & communication | 2011 |
| Akshar RUP Ltd | Wholesale & retail | 2015 |
| AKT Consultancy Ltd | Professional & scientific | 2026 |
| Akurate Management Company Limited | Financial services | 2016 |
| Akyno Global Limited | Health & social care | 2019 |
| AL Estates London Ltd | Real estate | 2016 |
| Al-Fasher Grilled Fish Restaurant Limited | Hospitality | 2025 |
| AL1 Properties Ltd | Real estate | 2025 |
| Alan Loren Limited | Wholesale & retail | 2023 |
| Alan Provisor Limited | Wholesale & retail | 1984 |
| Aland Cutz Ltd | Other services | 2020 |
| ALB Applied Waterproofing Ltd | Construction | 2025 |
| ALB Roofing Developments Ltd | Construction | 2019 |
| Alban Mews Management Company Limited | Real estate | 2023 |
| Albasayer Communications and Information Technology LLC Ltd | Information & communication | 2024 |
| Albion Hall Limited | Households | 2025 |