| Alto Seating Systems Limited | Manufacturing | 1995 |
| Alto Systems Holdings Limited | Professional & scientific | 1987 |
| Alto Systems Limited | Manufacturing | 2005 |
| Alto Tower Systems Limited | Manufacturing | 2000 |
| Altoirage Ltd | Other services | 2025 |
| Altra Estates Ltd | Real estate | 2025 |
| Altra Holdings Group Ltd | Financial services | 2025 |
| Altram L.R.T. Limited | Extraterritorial | 1993 |
| Altras International Limited | Information & communication | 2006 |
| Altreaus Ltd | Administrative & support | 2019 |
| Altrion Labs Limited | Wholesale & retail | 2026 |
| Altrix Services Limited | Wholesale & retail | 2025 |
| Altruist Enterprises UK Limited | Other services | 2013 |
| Altto Limited | Information & communication | 2025 |
| Altuna Group Ltd | Real estate | 2024 |
| Altura Innovations Ltd | Financial services | 2025 |
| Altura Property Development Ltd | Construction | 2025 |
| Altura Property Ltd | Real estate | 2025 |
| Altxorra Ltd | Wholesale & retail | 2025 |
| Aluhu Ltd | Manufacturing | 2026 |
| Alujo Ltd | Real estate | 2025 |
| Alulab Ltd | Manufacturing | 2022 |
| Alum Auto Spares Ltd | Wholesale & retail | 2018 |
| Alum Rock Button & Lace House Ltd | Construction | 2013 |
| Alum Rock Carpets Ltd | Wholesale & retail | 2026 |
| Alum Rock Halal Meat & Poultry Ltd | Wholesale & retail | 2023 |
| Alum Rock Traders Association Ltd | Administrative & support | 2022 |
| Alum ZEB Khan Ltd | Professional & scientific | 2026 |
| Alumet Systems (UK) Limited | Manufacturing | 1992 |
| Alumill Limited | Wholesale & retail | 2020 |
| Aluminium Casthouse Technologies Limited | Manufacturing | 2017 |
| Alumni Group Ltd | Information & communication | 2023 |
| Alumrock Butcher Ltd | Wholesale & retail | 2021 |
| Alumrock Cafe Limited | Hospitality | 2016 |
| Alumrock Pizza Limited | Hospitality | 2024 |
| Aluna Leisure Limited | Hospitality | 2014 |
| Alupanel Ltd | Professional & scientific | 2020 |
| Alupoint Windows Ltd | Manufacturing | 2025 |
| Aluring Ltd | Information & communication | 2026 |
| Alux Consultancy Limited | Real estate | 2018 |
| Aluxeskin Ltd | Other services | 2023 |
| Aluxia Glazing Limited | Wholesale & retail | 2022 |
| ALV Globaleducation Ltd | Education | 2025 |
| Alvand Ltd | Real estate | 2024 |
| Alvaran Care Ltd | Health & social care | 2025 |
| Alvaran Group Ltd | Professional & scientific | 2025 |
| Alvaran Security Ltd | Administrative & support | 2024 |
| Alvarium Fund Managers (UK) Limited | Financial services | 2015 |
| Alvarium Media Limited | Information & communication | 2016 |
| Alvechurch & Barnt Green Property Services Ltd | Households | 2020 |
| Alvechurch Communities Together Ltd | Other services | 2010 |
| Alvechurch Developments Limited | Real estate | 2021 |
| Alvechurch Dog Grooming Ltd | Other services | 2017 |
| Alvechurch FC Community Ltd | Arts & recreation | 2022 |
| Alvechurch Fisheries Limited | Wholesale & retail | 2008 |
| Alvechurch Football Club Limited | Arts & recreation | 1995 |
| Alvechurch Property Maintenance Services Ltd | Households | 2025 |
| Alverstone Property Ltd | Real estate | 2023 |
| Alveston Services Ltd | Construction | 2023 |
| Alveus Limited | Information & communication | 2022 |
| Alvi Asset Management UK Ltd | Information & communication | 2021 |
| Alvi Consultants Limited | Professional & scientific | 2025 |
| Alvi Locum Services Ltd | Health & social care | 2018 |
| Alvi Real Estates ( UK ) Ltd | Real estate | 2020 |
| Alvi Smiles Ltd | Health & social care | 2026 |
| Alvi Traders UK Ltd | Wholesale & retail | 2016 |
| Alvi's Group Ltd | Wholesale & retail | 2022 |
| Alvinsons Medical (PVT) Ltd | Manufacturing | 2018 |
| Alvita Transport Ltd | Wholesale & retail | 2019 |
| Alviz Studios Ltd | Professional & scientific | 2025 |
| ALW Sales Ltd | Professional & scientific | 2018 |
| Alwajih Machinery Sales Limited | Hospitality | 2012 |
| Always a Mistry Limited | Information & communication | 2011 |
| Always Antiques 1954 Ltd | Wholesale & retail | 2023 |
| Always Antiques Limited | Wholesale & retail | 2021 |
| Always Buying (Group) Ltd | Wholesale & retail | 2026 |
| Always Clean Regardless Ltd | Administrative & support | 2025 |
| Always Driven Limited | Transport & logistics | 2025 |
| Always Green Lawns Ltd | Administrative & support | 2010 |
| Always HPD Ltd | Professional & scientific | 2022 |
| Alwayse Engineering Limited | Manufacturing | 1940 |
| Alwayse Futures Limited | Financial services | 2022 |
| Alwayse Next Investments Limited | Professional & scientific | 2008 |
| Alwyn Court Freeholders Limited | Real estate | 2003 |
| Alwynn Management Company Limited | Households | 1989 |
| Alyaqeen Ltd | Education | 2021 |
| Alycidon Capital Limited | Manufacturing | 2011 |
| Alyoco Ltd | Wholesale & retail | 2018 |
| Alyph Technologies Ltd | Wholesale & retail | 2025 |
| Alyru Hub Ltd | Wholesale & retail | 2025 |
| Alysofi Ltd | Transport & logistics | 2023 |
| Alyss Capital Limited | Real estate | 2021 |
| Alyxon Limited | Wholesale & retail | 2026 |
| Alyzah Limited | Wholesale & retail | 2019 |
| ALZ Collection Ltd | Wholesale & retail | 2025 |
| Alzerje Medical Ltd | Health & social care | 2022 |
| Alzibak Ltd | Other services | 2022 |
| Alzie Limited | Administrative & support | 2021 |
| AM & CN Ltd | Health & social care | 2021 |
| AM & LM Limited | Administrative & support | 2018 |