| Alphonsus Homes Limited | Real estate | 2011 |
| Alphonsus Services (Dudley) Limited | Other services | 2005 |
| Alphonsus Services Limited | Other services | 1992 |
| Alpin Telecom Ltd | Construction | 2023 |
| Alpina Cars Limited | Wholesale & retail | 2018 |
| Alpine Advert Ltd | Information & communication | 2025 |
| Alpine Care UK Limited | Health & social care | 2007 |
| Alpine Education Group Ltd | Education | 2023 |
| Alpine PAY Limited | Administrative & support | 2025 |
| Alpine Real Estate Limited | Real estate | 2005 |
| Alpine Security Services Limited | Administrative & support | 2022 |
| Alpine Vista Productions Ltd | Wholesale & retail | 2023 |
| Alps Accountants Limited | Professional & scientific | 2010 |
| Alps Planning and Building Services Limited | Professional & scientific | 2026 |
| Alps Property and Maintenance Limited | Construction | 2016 |
| Alqab Mobiles Ltd | Wholesale & retail | 2015 |
| Alquddus Sayyid Academy CIC | Education | 2024 |
| ALR Performance Ltd | Wholesale & retail | 2026 |
| Alrahma Cafeteria Ltd | Hospitality | 2025 |
| Alrahmah Foundation for Education & Development | Administrative & support | 2016 |
| Alrahman Motor Factors Ltd | Wholesale & retail | 2020 |
| Alrakooba Jabana Ltd | Hospitality | 2025 |
| Alreadymade Ltd | Real estate | 2023 |
| Alrep London Ltd | Manufacturing | 2023 |
| Alright BAB Ltd | Information & communication | 2024 |
| Alrob Group Ltd | Manufacturing | 2024 |
| Alrousan Medical Ltd | Health & social care | 2024 |
| Alrufaei Ltd | Wholesale & retail | 2024 |
| ALS Enterprise Ltd | Professional & scientific | 2022 |
| ALS Medical Services Limited | Health & social care | 2025 |
| Alsadiq&Sons Logistics Service Limited | Manufacturing | 2022 |
| Alsaif Dyers Ltd | Other services | 2024 |
| Alsaif Tasty Food Ltd | Hospitality | 2026 |
| Alsakkaf Tradings Limited | Wholesale & retail | 2025 |
| Alsaqqaf Ltd | Real estate | 2025 |
| Alsaraf Ltd | Transport & logistics | 2023 |
| Alsata Removals Limited | Transport & logistics | 2019 |
| Alsbre Company Ltd | Wholesale & retail | 2014 |
| Alsemt Ltd | Wholesale & retail | 2026 |
| Alset Property Holdings Limited | Financial services | 2025 |
| Alset Property Limited | Real estate | 2025 |
| Alshaam Enterprise Ltd | Wholesale & retail | 2025 |
| Alshameri and Sons Ltd | Wholesale & retail | 2026 |
| Alshameri Ltd | Administrative & support | 2018 |
| Alshameri Pick UP Limited | Other services | 2019 |
| Alsiekh Limited | Administrative & support | 2025 |
| Alsinclair Holdings Limited | Arts & recreation | 2016 |
| Alsinclair Property Holdings Ltd | Real estate | 2025 |
| Alson's Property Limited | Real estate | 2021 |
| Alsons Logistics Ltd | Wholesale & retail | 2020 |
| Alsouks Ltd | Wholesale & retail | 2023 |
| Alston Limestone Company (the) Limited | Extraterritorial | 1908 |
| Alsuk Limited | Wholesale & retail | 2022 |
| Alsure Holdings Limited | Financial services | 2024 |
| Alsure Limited | Manufacturing | 1992 |
| ALT Xxvi Ltd | Information & communication | 2018 |
| ALT ZME Ltd | Manufacturing | 2023 |
| Alta Birmingham China Limited | Other services | 2005 |
| Alta Cyclotron Services Limited | Manufacturing | 2011 |
| Altacor Limited | Professional & scientific | 2005 |
| Altaf Brothers Limited | Wholesale & retail | 2025 |
| Altaf Corporation Ltd | Wholesale & retail | 2026 |
| Altaf Shaikh Contracting Limited | Administrative & support | 2019 |
| Altaf Sons Ltd | Wholesale & retail | 2025 |
| Altanex Holdings Limited | Financial services | 2025 |
| Altarf Limited | Professional & scientific | 2018 |
| Altas Enterprises Ltd | Wholesale & retail | 2024 |
| Altastic Limited | Wholesale & retail | 2024 |
| Altayyar House (Flat 13) Limited | Real estate | 2024 |
| Altayyar House (Flat 14) Limited | Real estate | 2024 |
| Altera Healthcare (IT) UK Ltd | Wholesale & retail | 2011 |
| Alterations for Special Occasions Limited | Other services | 2016 |
| Alterbiome Limited | Health & social care | 2025 |
| Altered Skin CIC | Arts & recreation | 2019 |
| Alteredmedia Ltd | Real estate | 2017 |
| Altermata Ltd | Professional & scientific | 2024 |
| Alterna Market Ltd | Hospitality | 2024 |
| Alternate Worlds Limited | Wholesale & retail | 2005 |
| Alternative Communications Systems Ltd | Administrative & support | 2005 |
| Alternative Global Solutions Ltd | Professional & scientific | 2014 |
| Alternative Housing Services WM Limited | Health & social care | 2018 |
| Alternative Intelligent Solutions Ltd | Wholesale & retail | 2017 |
| Alternative Records Ltd | Wholesale & retail | 2010 |
| Alternos Consultants Ltd | Information & communication | 2024 |
| Alti Asset Management Holdings 2 Limited | Financial services | 2014 |
| Alti Asset Management Holdings Limited | Financial services | 2021 |
| Alti Pradera Holdings Limited | Financial services | 2016 |
| Alti RE Limited | Financial services | 2009 |
| Alti RE Public Markets Limited | Financial services | 2022 |
| Alti Strategic Advisory (UK) Limited | Financial services | 2018 |
| Altin Ltd | Professional & scientific | 2022 |
| Altinn Solution Limited | Administrative & support | 2026 |
| Altion Limited | Wholesale & retail | 1994 |
| Altiora Concierge Ltd | Other services | 2026 |
| Altitud Group Limited | Construction | 2025 |
| Altitude Build Limited | Real estate | 2024 |
| Altitude Drive Automotive Ltd | Administrative & support | 2026 |
| Altitude Healthcare Ltd | Health & social care | 2023 |
| Altitude Properties Limited | Real estate | 2018 |
| Altitude Property Management Company Limited | Households | 2006 |