| Alex Solomon Consulting Ltd | Professional & scientific | 2021 |
| Alex Summersby Limited | Information & communication | 2012 |
| Alex Williamson Illustration Limited | Arts & recreation | 2014 |
| Alexander MAE (HR) Ltd | Administrative & support | 2009 |
| Alexandra Hardman Ltd | Administrative & support | 2022 |
| Alexandra Hunt Trading Ltd | Professional & scientific | 2015 |
| Alexandra Tulloch Ltd | Other services | 2021 |
| Alexian Ltd | Information & communication | 2007 |
| Alexpizza Ltd | Hospitality | 2023 |
| Alexsys Communications Limited | Information & communication | 2000 |
| Alfred Street Holdings Limited | Real estate | 2022 |
| Algha Group Limited | Manufacturing | 1996 |
| Alhc (Holdings) Limited | Administrative & support | 2016 |
| ALI Baba Fresh Food Ltd | Hospitality | 2025 |
| Alice Grace Design Ltd | Professional & scientific | 2024 |
| Alice Grace Ltd | Wholesale & retail | 2023 |
| Alice Park Ltd | Professional & scientific | 2024 |
| Align Body Clinic Ltd | Other services | 2003 |
| Aligned CLS Ltd | Real estate | 2021 |
| Aligned to Wellness Ltd | Health & social care | 2021 |
| Alimo Consultants Limited | Professional & scientific | 2019 |
| Alison Keith Limited | Health & social care | 2018 |
| Alistair Bradley Coaching Ltd | Professional & scientific | 2015 |
| Alithis Holdings Ltd | Financial services | 2015 |
| Alixr Ltd | Arts & recreation | 2024 |
| ALL Aspect Builders (Bath) Ltd | Construction | 2015 |
| ALL Building Matters Limited | Construction | 2006 |
| ALL Point Exterior Ltd | Administrative & support | 2026 |
| ALL Saints Properties Limited | Real estate | 2000 |
| ALL Seasons MAN Limited | Arts & recreation | 2024 |
| ALL2 Limited | Professional & scientific | 2026 |
| Allenby Maintenance Limited | Households | 1986 |
| Alleviate Hospitality Ltd | Professional & scientific | 2021 |
| Allied Property Ltd | Real estate | 2004 |
| Allume Digital Limited | Professional & scientific | 2013 |
| ALM Counselling Ltd | Health & social care | 2024 |
| Almond Electrics Limited | Construction | 2014 |
| Almscliffe Capital Ltd | Financial services | 2026 |
| Alpha House Wealth Management Limited | Financial services | 2019 |
| Alpha Live in Care Ltd | Health & social care | 2021 |
| Alpha Tango 2 Ltd | Real estate | 2024 |
| Altaine UK Limited | Information & communication | 2002 |
| Alterd Ltd | Professional & scientific | 2020 |
| Altergen Ltd | Manufacturing | 2020 |
| Alternative Source | Other services | 2010 |
| Althea Anaesthesia Limited | Health & social care | 2025 |
| Altibar Ltd | Hospitality | 2026 |
| Altitude Holdings Limited | Real estate | 2021 |
| Altitude Lets Ltd | Real estate | 2022 |
| Alton Place Developments Ltd | Construction | 2022 |
| Altoria Global Limited | Wholesale & retail | 2023 |
| Altus Consulting Holding Limited | Information & communication | 2015 |
| Altus Consulting Limited | Information & communication | 2005 |
| Alvarado Street Limited | Professional & scientific | 2026 |
| Always Onwards Ltd. | Professional & scientific | 2012 |
| Alwood Care Limited | Health & social care | 2019 |
| Alwood Support Ltd | Health & social care | 2026 |
| AM Scaffolding Bath Ltd | Construction | 2023 |
| Amahar Limited | Wholesale & retail | 2018 |
| Amakati Ltd | Information & communication | 2018 |
| Amalfie Farming Limited | Agriculture & fishing | 2018 |
| Amali Jules Ltd | Wholesale & retail | 2012 |
| Amaniti Ltd | Information & communication | 2024 |
| Amatis Training Ltd | Administrative & support | 2018 |
| Amaze Games Ltd | Information & communication | 2024 |
| Amazement Machines Limited | Information & communication | 2020 |
| Amazigh Ventures Limited | Information & communication | 2020 |
| Ambd Consultancy Ltd | Administrative & support | 2015 |
| Amber Financial Investments Limited | Financial services | 2011 |
| Amber Makes Limited | Wholesale & retail | 2022 |
| Ambiance Properties Ltd | Real estate | 2015 |
| Ambient Engineering Limited | Manufacturing | 2005 |
| Ambr Corporation Limited | Professional & scientific | 2020 |
| Amenz Construction Ltd. | Construction | 1998 |
| American Museum Enterprises Limited | Wholesale & retail | 1950 |
| American Nails & Beauty Ltd | Other services | 2019 |
| American Optical UK Limited | Administrative & support | 2015 |
| Ametia Properties Limited | Real estate | 2024 |
| Amgb Properties Ltd | Real estate | 2022 |
| AMH Building Services Ltd | Construction | 2015 |
| Amico Fashion UK Ltd | Wholesale & retail | 2024 |
| Amicus Foster Care Limited | Health & social care | 2008 |
| Amieinchina Ltd | Professional & scientific | 2026 |
| Amirali Howard Consulting Limited | Professional & scientific | 2018 |
| Amiston Limited | Manufacturing | 2019 |
| Ammarco Limited | Real estate | 2026 |
| Ammique Limited | Wholesale & retail | 2003 |
| Ammique Production Ltd | Financial services | 2020 |
| Ammique Sleepscape Hotels Limited | Hospitality | 2022 |
| Amoeba Tech Ltd | Professional & scientific | 2023 |
| Amplifychange | Financial services | 2020 |
| Amplitudeevents Ltd | Administrative & support | 2019 |
| Amrd Consulting Limited | Administrative & support | 2021 |
| AMY Jones Architects Ltd | Professional & scientific | 2024 |
| AMY Manning Investments Limited | Real estate | 2022 |
| An&Ca Ltd | Hospitality | 2016 |
| Anaco Bath Limited | Wholesale & retail | 2020 |
| Anaerobic Digestion Systems Limited | Professional & scientific | 2017 |
| Analytically Minded Limited | Professional & scientific | 2015 |
| ANC Systems Limited | Information & communication | 2005 |