| ALT Production Group Limited | Information & communication | 2026 |
| Alt.A Transport Limited | Transport & logistics | 2018 |
| Alta Properties Limited | Real estate | 1989 |
| Altaan Medic Ltd | Professional & scientific | 2025 |
| Altaf Capital Developments Ltd | Construction | 2025 |
| Altair (Ice Rink) Ltd | Real estate | 2020 |
| Altair Property Management Ltd | Administrative & support | 2016 |
| Altair Signage Ltd | Other services | 2023 |
| Altaj Brothers UK Ltd | Wholesale & retail | 2023 |
| Altaj Limited | Administrative & support | 2025 |
| Altara Advisory Ltd | Professional & scientific | 2019 |
| Altaro UK Limited | Information & communication | 2016 |
| Altas Beta Ltd | Wholesale & retail | 2026 |
| Altass Limited | Professional & scientific | 2020 |
| Altaterra Group Limited | Other services | 2015 |
| Altayb Limited | Other services | 2016 |
| Altcom 270 Limited | Professional & scientific | 2000 |
| Altec Network Solutions Ltd | Information & communication | 2007 |
| Altech Group Ltd | Administrative & support | 2023 |
| Alterations Boutique MCR Ltd | Other services | 2025 |
| Alterations Centre Ltd | Other services | 2015 |
| Alterations Specialist Ltd | Professional & scientific | 2023 |
| Alterline Research Limited | Administrative & support | 2010 |
| Alternate Energy Efficiency Solutions Ltd | Other services | 2019 |
| Alternatev Ltd | Professional & scientific | 2019 |
| Alternative Coffee Limited | Manufacturing | 2019 |
| Alternative Groove Limited | Other services | 2021 |
| Alternative to Hotel Limited | Hospitality | 2011 |
| Alternativo Ltd | Administrative & support | 2016 |
| Alterytis HR Ltd | Wholesale & retail | 2020 |
| Altezza Limited | Administrative & support | 2018 |
| Althahm Almontaliq Lelamaal Ltd | Wholesale & retail | 2025 |
| Alti Procurements Ltd | Public administration | 2026 |
| Altieri Estates Limited | Real estate | 2024 |
| Altimus Canal Bridge Limited | Construction | 2026 |
| Altimus Clarence Grove Limited | Construction | 2026 |
| Altimus Developments Limited | Construction | 2022 |
| Altimus Holding Co Limited | Financial services | 2026 |
| Altissimus Limited | Real estate | 2025 |
| Altitude 1850 Ltd | Financial services | 2022 |
| Altius General Trading Ltd | Extraterritorial | 2026 |
| Altius Properties Limited | Real estate | 2016 |
| Altivo Premium Management Limited | Hospitality | 2026 |
| Altivus Limited | Information & communication | 2025 |
| Alto Coatings UK Ltd | Construction | 2025 |
| Altogether Human CIC | Health & social care | 2020 |
| Altogether Otherwise Limited | Professional & scientific | 2023 |
| Alton's Barbershop Ltd | Other services | 2022 |
| Altonus Limited | Wholesale & retail | 2023 |
| Altra Concept Ltd | Professional & scientific | 2024 |
| Altrglo Ltd | Wholesale & retail | 2024 |
| Altrincham Basement and Cellar Conversions Limited | Professional & scientific | 2009 |
| Altrincham Building and Damp-Proofing Limited | Construction | 2004 |
| Altrincham Driveways Ltd | Administrative & support | 2026 |
| Altrincham Park Properties Ltd | Real estate | 2024 |
| Altrincham Property Ltd | Households | 2022 |
| Altrix Technology Ltd | Administrative & support | 2018 |
| Altruist NW Ltd | Information & communication | 2025 |
| Altryn Sportswear Ltd | Wholesale & retail | 2022 |
| Altsol Beauty Ltd | Other services | 2026 |
| Altura Apparel Ltd | Wholesale & retail | 2025 |
| Altura Climbing Limited | Wholesale & retail | 2026 |
| Alturon for International Services Limited | Extraterritorial | 2026 |
| Altus Services Limited | Professional & scientific | 2026 |
| Altus Social Ltd | Hospitality | 2022 |
| Altus Trading & Contracting Ltd | Other services | 2023 |
| Altvora Ltd | Wholesale & retail | 2025 |
| Alty Hotel Ltd | Hospitality | 2025 |
| Aluex Systems Ltd | Construction | 2014 |
| Aluk Motors Ltd | Wholesale & retail | 2014 |
| Alula Cafe Ltd | Hospitality | 2025 |
| Alumaa Limited | Transport & logistics | 2019 |
| Aluminium and Building Projects Ltd | Construction | 2020 |
| Aluminium Facades UK Limited | Construction | 2016 |
| Aluminium Machinery Services Ltd | Manufacturing | 2020 |
| Aluminium World Ltd | Wholesale & retail | 2024 |
| Alun Vaughan Consultancy Limited | Professional & scientific | 2023 |
| Aluna Home Group Ltd | Real estate | 2026 |
| Alupigus Greuceanu Limited | Administrative & support | 2025 |
| Aluplas Ltd | Construction | 2023 |
| Alure ZEN Cosmetic Supplies Ltd | Wholesale & retail | 2021 |
| Alusia Consultancy Limited | Information & communication | 2012 |
| Alux Trading Limited | Wholesale & retail | 2022 |
| Alvarez Beauty Pro Ltd | Wholesale & retail | 2026 |
| Alvera Hospitality Ltd | Other services | 2022 |
| Alvest Limited | Professional & scientific | 2016 |
| Alveus Development (UK) Ltd | Construction | 2019 |
| Alvey Acquisitions Ltd | Real estate | 2025 |
| Alvi Driving School Ltd | Education | 2026 |
| Alvi Group Ltd | Extraterritorial | 2025 |
| Alviens Ltd | Construction | 2020 |
| Alvies Limited | Wholesale & retail | 2024 |
| Alvin Hubs Ltd | Information & communication | 2023 |
| Alvionz Ltd | Wholesale & retail | 2025 |
| Alvisual UK Ltd | Real estate | 2003 |
| Alwaal for Trading Ltd | Wholesale & retail | 2024 |
| Alwadi Investment Limited | Wholesale & retail | 2025 |
| Alwafi Plus for Trading Ltd | Wholesale & retail | 2026 |
| Alwalibro Ltd | Real estate | 2026 |
| Alwasal Investment Limited | Wholesale & retail | 2025 |