| Alex James Property Ltd | Real estate | 2019 |
| Alexander Anthony Ltd | Extraterritorial | 2019 |
| Alexander Crest Homes Ltd | Real estate | 2020 |
| Alexander James (Solihull) Limited | Other services | 2018 |
| Alexandra Palmer Copywriting Ltd | Professional & scientific | 2021 |
| Alfresco Fusion Hall Green Limited | Hospitality | 2026 |
| Alfresco Fusion Ltd | Hospitality | 2017 |
| ALI Hammad Co Ltd | Wholesale & retail | 2025 |
| ALI Hussain Haulage Ltd | Transport & logistics | 2025 |
| ALI Sada Ltd | Health & social care | 2019 |
| ALIA3D2Y Limited | Health & social care | 2024 |
| Alice Knox Psychotherapy Ltd | Health & social care | 2026 |
| Alice Rose & Co Ltd. | Professional & scientific | 2016 |
| Align Technology UK Limited | Health & social care | 2001 |
| Alisa Optics Ltd | Health & social care | 2023 |
| Alison Browne HR Ltd | Administrative & support | 2024 |
| Alistair Turner Ltd | Administrative & support | 2019 |
| Alive Audio Limited | Administrative & support | 2019 |
| ALK Auto Ltd | Manufacturing | 2026 |
| Alka Developments Ltd | Construction | 2022 |
| Alkapharm UK Limited | Wholesale & retail | 1995 |
| ALL Active Sports Ltd | Education | 2012 |
| ALL Boxed UP Ltd | Water & waste | 2023 |
| ALL Cylinders Competitions Limited | Wholesale & retail | 2026 |
| ALL Event Catering Limited | Hospitality | 2019 |
| ALL in One Maintenance Midlands Limited | Administrative & support | 2014 |
| ALL Network Technology Limited | Information & communication | 2020 |
| ALL Round Environmental Solutions UK Ltd | Administrative & support | 2024 |
| ALL Things IT Limited | Information & communication | 2025 |
| Allan Alistair Bailey Limited | Extraterritorial | 2026 |
| Allbatteries Limited | Manufacturing | 1992 |
| Allens Caravans Limited | Extraterritorial | 1947 |
| Alleyhaus Ltd | Construction | 2022 |
| Allflo Limited | Wholesale & retail | 2020 |
| Allgass Ltd | Professional & scientific | 2026 |
| Alliance Living Housing Association | Real estate | 2022 |
| Alliance Success Limited | Administrative & support | 2024 |
| Allied SX Ltd | Information & communication | 2016 |
| Allison Homes Eastern Limited | Extraterritorial | 2001 |
| Allseasons Maintenance Ltd | Construction | 2016 |
| Allseasons Refurbishment Ltd | Construction | 2021 |
| Alltru Limited | Professional & scientific | 2024 |
| Allure Aesthetics & Beauty Ltd | Other services | 2022 |
| Alluri Properties Limited | Real estate | 2023 |
| Allyr Consulting Ltd | Professional & scientific | 2019 |
| ALM Globaltech Holdings Limited | Financial services | 2025 |
| ALM Translations Limited | Information & communication | 2002 |
| Almujtaba | Education | 2025 |
| Alne Estates. | Agriculture & fishing | 1948 |
| Alpha Laser Solutions Limited | Manufacturing | 2022 |
| Alpha Partnership (IFA) Limited | Administrative & support | 2005 |
| Alpha Plus Midlands Ltd | Health & social care | 2020 |
| Alpha Premier Contractors Ltd | Construction | 2022 |
| Alpha Project Services Ltd | Professional & scientific | 2025 |
| Alpha Script Medical Writing Ltd | Professional & scientific | 2025 |
| Alpha Seeds Ltd | Other services | 2013 |
| Alphabet Street Advisory Limited | Professional & scientific | 2022 |
| Alphadataanalytics Limited | Information & communication | 2024 |
| Alphapak International Limited | Administrative & support | 2018 |
| Alphonse Dineen Hair Studio Limited | Other services | 2002 |
| Alpler Agricultural Machinery Sales Limited | Wholesale & retail | 2022 |
| ALR PT Ltd | Health & social care | 2025 |
| Alsaeed Properties Limited | Real estate | 2026 |
| Alshaafi Online Ltd | Wholesale & retail | 2025 |
| Altas Consultancy Solutions Limited | Information & communication | 2023 |
| Alternative Integration Solutions Limited | Information & communication | 2025 |
| Altis Automotive Limited | Information & communication | 2026 |
| Altis Holdings Limited | Financial services | 2026 |
| Altitude Homes Ltd | Real estate | 2022 |
| Altovplan Limited | Administrative & support | 2015 |
| Altsi's Ltd | Other services | 2017 |
| Altum Aviation Maintenance Ltd | Manufacturing | 2025 |
| Altum Homes Ltd | Construction | 2025 |
| Aluca UK Ltd. | Manufacturing | 2025 |
| Aluminium Duffel UK Limited | Administrative & support | 2025 |
| Alushi Systems Limited | Professional & scientific | 2025 |
| Alvechurch Kitchens Ltd | Wholesale & retail | 2024 |
| Always on the Glow Ltd | Other services | 2025 |
| ALX Networks Ltd | Construction | 2025 |
| Alyshoptool Ltd | Construction | 2025 |
| AM Autos Limited | Wholesale & retail | 2000 |
| AM Corporate Ltd | Professional & scientific | 2026 |
| AM Cousultants Ltd | Professional & scientific | 2024 |
| AM Dent Limited | Health & social care | 2023 |
| Aman Care Limited | Administrative & support | 2009 |
| Aman Rosie Investments Limited | Real estate | 2021 |
| Amanah Family Centre Community Interest Company | Information & communication | 2022 |
| Amanda Jayne Home Interiors Limited | Wholesale & retail | 2025 |
| Amandor Limited | Professional & scientific | 2007 |
| Amaniiphotography Limited | Professional & scientific | 2024 |
| Amar Natures Treasures Ltd | Wholesale & retail | 2025 |
| Amazing Prop Trader Limited | Financial services | 2024 |
| Amazingdiningshirley Ltd | Hospitality | 2025 |
| Amazon Civils Limited | Extraterritorial | 2006 |
| Amazoon Limited | Wholesale & retail | 2026 |
| AMB Event Solutions Ltd | Professional & scientific | 2023 |
| Ambassador Court Limited | Hospitality | 1981 |
| Amber Advisory Limited | Professional & scientific | 2008 |
| Amber Farming Company Limited | Agriculture & fishing | 1997 |
| Amber Lane Properties Ltd | Real estate | 2024 |