| Aliance Delivery Ltd | Wholesale & retail | 2025 |
| Alium Homes Limited | Real estate | 2021 |
| ALJ Property Services Ltd | Real estate | 2025 |
| ALL Approved Ltd | Manufacturing | 2023 |
| ALL Engines Limited | Wholesale & retail | 2021 |
| ALL Natural Feeding Ltd | Wholesale & retail | 2022 |
| ALL RAW Ltd | Wholesale & retail | 2021 |
| ALL Seasons Yard Limited | Real estate | 2018 |
| ALL That Food Limited | Wholesale & retail | 2014 |
| ALL the Home Limited | Wholesale & retail | 2020 |
| Allbets Caredoc Limited | Health & social care | 2021 |
| Alleyrival Limited | Hospitality | 1986 |
| Allied 247 Ltd | Administrative & support | 2024 |
| Allied Health Staffing Solutions Limited | Administrative & support | 2018 |
| Alliric Properties Ltd | Real estate | 2021 |
| Allneeds Care Limited | Health & social care | 2023 |
| Allpropuk Limited | Real estate | 2013 |
| Almas Coffee Limited | Wholesale & retail | 2021 |
| Almond Court Buckhurst Hill Management Limited | Hospitality | 2013 |
| Alpan Properties Limited | Administrative & support | 2021 |
| Alpcan Properties Limited | Real estate | 2017 |
| Alpha AK Ltd | Administrative & support | 2024 |
| Alpha Security Group Ltd | Administrative & support | 2025 |
| Alpha Shield Protection Ltd | Administrative & support | 2025 |
| Alpha State Fitness Ltd | Arts & recreation | 2019 |
| Alpha UOM Ltd | Real estate | 2018 |
| Alphablue Limited | Other services | 2017 |
| Alphera Holding Limited | Wholesale & retail | 2024 |
| Alphera Medical Limited | Manufacturing | 2024 |
| Alsa Consulting Ltd | Administrative & support | 2024 |
| ALT MLK Limited | Manufacturing | 2024 |
| Alternative Journey Ltd | Professional & scientific | 2020 |
| Altin Builders Ltd | Construction | 2022 |
| Altman, Perry and Young Limited | Real estate | 2016 |
| Altrasta Capital Limited | Financial services | 2017 |
| ALX Productions Ltd | Construction | 2023 |
| AM Air Conditioning (UK) Limited | Energy | 2007 |
| AM CAP Limited | Administrative & support | 2018 |
| AM Coffee Holdings Limited | Administrative & support | 2018 |
| AM Fahh Holdings Ltd | Financial services | 2025 |
| AM Innovation Consultancy Ltd | Extraterritorial | 2013 |
| AMA Property & Management Ltd | Construction | 2023 |
| Amaan Healthcare Limited | Health & social care | 2023 |
| Amai Clothing Ltd | Wholesale & retail | 2024 |
| Amai Shop Ltd | Wholesale & retail | 2024 |
| Amari and ME Homes Limited | Real estate | 2019 |
| Amarni Management Ltd | Construction | 2018 |
| Amarok London Limited | Construction | 2024 |
| Amazing Solutions Limited | Construction | 2011 |
| Amba Real Estate Ltd | Real estate | 2023 |
| Ambassador of London Limited | Wholesale & retail | 2013 |
| Ambassador Square Cheshunt Ltd | Households | 2024 |
| Amberrye Limited | Administrative & support | 2014 |
| Ambien Group Ltd | Information & communication | 2009 |
| Ambika Consulting and Finance Services Ltd | Real estate | 2015 |
| AMC Land Investments Ltd | Real estate | 2017 |
| Amcy Technology Limited | Information & communication | 2006 |
| AMD Interior Architecture Limited | Professional & scientific | 2016 |
| Ameenah Management Limited | Construction | 2017 |
| Ameone Limited | Administrative & support | 2008 |
| Amerifine UK Ltd | Wholesale & retail | 2016 |
| Amgu Ltd | Professional & scientific | 2025 |
| Amhaus Limited | Hospitality | 2012 |
| Amhurst Arms Ltd | Hospitality | 2013 |
| Amhurst Park Residents Association Limited | Households | 1976 |
| AMJ Star Ltd | Wholesale & retail | 2021 |
| AML Futures Limited | Construction | 2024 |
| AMM Build UK Ltd | Construction | 2023 |
| AMN Limited | Construction | 2026 |
| Amno Group Ltd | Administrative & support | 2025 |
| Amnt Properties UK Limited | Real estate | 2016 |
| Amonra Services Limited | Administrative & support | 2011 |
| Amoor Accountants Limited | Professional & scientific | 2017 |
| Amplifyingcareers Ltd | Professional & scientific | 2025 |
| Amplinth UK Limited | Information & communication | 2026 |
| Ampm Maintenance Limited | Professional & scientific | 2008 |
| Amrit Lila (UK) Ltd | Financial services | 2025 |
| AMS Chartering Ltd | Transport & logistics | 2021 |
| AMS Interims (Consultancy) Ltd | Administrative & support | 2017 |
| AMS Management Consulting Limited | Real estate | 2022 |
| AMS Residential Limited | Real estate | 2022 |
| Amuera Ltd | Wholesale & retail | 2024 |
| Amworth Ltd | Wholesale & retail | 2023 |
| ANA Flores Limited | Professional & scientific | 2025 |
| Analect Capital Management Ltd | Administrative & support | 2017 |
| Analytical and Numerical Solutions Limited | Information & communication | 2010 |
| Anandadhara Arts Limited | Arts & recreation | 2016 |
| Anatomy Education Ltd | Wholesale & retail | 2020 |
| ANB Consulting Services Limited | Information & communication | 2016 |
| ANB Property Limited | Real estate | 2017 |
| Anchusa Holdings Limited | Financial services | 2023 |
| Ancient Treasures Ltd | Wholesale & retail | 2018 |
| Andreas Alexander & Co. Limited | Extraterritorial | 2025 |
| Andreas Alexander Limited | Extraterritorial | 2025 |
| Andreas Anna Alexander Ltd | Extraterritorial | 2025 |
| Andreas Kounnis Limited | Professional & scientific | 2018 |
| Andrei&Rares Construction Limited | Construction | 2018 |
| Andrews Archway Limited | Financial services | 2018 |
| Andriy Builders Limited | Construction | 2017 |
| Andy Newman Consultancy Limited | Administrative & support | 2016 |