| Altena Education Ltd | Education | 2021 |
| Altena Ltd | Other services | 2018 |
| Alternative Community Education Ltd | Education | 2021 |
| Alternative Landfill Solutions Limited | Extraterritorial | 2013 |
| Alternative Management Limited | Professional & scientific | 2010 |
| Alterra Advisory Group Limited | Information & communication | 2026 |
| Altmart Ltd | Wholesale & retail | 2026 |
| Alucard Limited | Information & communication | 2019 |
| Aluko IT Solutions Ltd | Information & communication | 2022 |
| Alumae Ltd | Wholesale & retail | 2025 |
| Alumfit Ltd | Real estate | 2018 |
| Alumnor Infosec Ltd | Information & communication | 2021 |
| Aluré Hair & Beauty Limited | Other services | 2018 |
| Aluzion Ltd | Administrative & support | 2017 |
| ALV Group Ltd | Real estate | 2024 |
| Alvea Living Limited | Construction | 2024 |
| Alverstoke Automotive Ltd | Wholesale & retail | 2021 |
| Alverstoke Properties Ltd | Real estate | 2025 |
| Alygarage Ltd | Wholesale & retail | 2024 |
| Alyssa Mair Limited | Wholesale & retail | 2021 |
| Alyzain Limited | Public administration | 2025 |
| Alzec Vision C.I.C. | Real estate | 2016 |
| AM Health Ltd | Public administration | 2021 |
| AM JD White Limited | Administrative & support | 2017 |
| AM Tiles Limited | Construction | 2018 |
| AM Traders U.K. Ltd | Construction | 2025 |
| Amadeus Foods Limited | Hospitality | 2024 |
| Aman Parmar Limited | Construction | 2015 |
| Amandi Companions Limited | Health & social care | 2018 |
| Amar Trading 25 Ltd | Wholesale & retail | 2024 |
| Amara Enterprises Ltd | Real estate | 2014 |
| Amaranthpoem Ltd | Administrative & support | 2020 |
| Amaray Properties Limited | Real estate | 2021 |
| Amardeep Devgun Ltd | Other services | 2018 |
| Amatrix Global Limited | Information & communication | 2025 |
| Amaya Chairs Ltd | Professional & scientific | 2022 |
| Amaze Clothing Co. Limited | Wholesale & retail | 1999 |
| Amaze Limited | Extraterritorial | 2025 |
| Amazing Burger Ltd | Hospitality | 2023 |
| Amazing World of Toys Ltd | Wholesale & retail | 2021 |
| Amazu Global Ltd | Wholesale & retail | 2025 |
| Ambala Box Limited | Wholesale & retail | 2025 |
| Ambar Transport Ltd | Transport & logistics | 2019 |
| Amber & AVA Ltd | Health & social care | 2012 |
| Amber Education Ltd | Education | 2017 |
| Amber Finance (Bains) Ltd | Financial services | 2013 |
| Ambient Air Conditioning Holdings Limited | Professional & scientific | 2009 |
| Ambient Group Limited | Financial services | 2017 |
| Amblemanor Limited | Extraterritorial | 1985 |
| Ambleside Homes (Midlands) Ltd | Real estate | 2024 |
| AMD Properties Midlands Ltd | Real estate | 2023 |
| Amd-Bolgari Ltd | Hospitality | 2018 |
| Amdseo Ltd | Information & communication | 2023 |
| Ameen E Commerce Ltd | Wholesale & retail | 2026 |
| Amen UK Limited | Manufacturing | 2019 |
| Amethyst Academies Trust | Education | 2012 |
| Amethyst Care & Recruitment Ltd | Health & social care | 2016 |
| AMG Creative Arts CIC | Information & communication | 2026 |
| AMG Fibre Comms Ltd | Construction | 2020 |
| AMG Property Investments Ltd | Real estate | 2024 |
| AMG Site Services Limited | Administrative & support | 2023 |
| AMG Technologies Ltd | Information & communication | 2022 |
| AMI Motorcycles Ltd | Wholesale & retail | 2023 |
| Amiable Retail Ltd | Wholesale & retail | 2022 |
| Amici Midlands Limited | Hospitality | 2013 |
| Amicus International Foundation | Professional & scientific | 2024 |
| Amigo Burrito Ltd | Hospitality | 2026 |
| Amikky Drylining Ltd | Construction | 2019 |
| Amin Capital Limited | Real estate | 2023 |
| Amin Enterprises Limited | Extraterritorial | 1994 |
| Amin Imperial Bakeries Limited | Manufacturing | 2011 |
| Amina Gardens (Management Company) Limited | Real estate | 2020 |
| AMIS779 Ltd | Health & social care | 2012 |
| AMK Management Services Limited | Administrative & support | 2025 |
| Amkk Property Limited | Real estate | 2026 |
| AML Heatpump Solutions Ltd | Construction | 2026 |
| AML Holdings Ltd | Financial services | 2019 |
| Ammy Construction Limited | Construction | 2025 |
| AMN Solutions Limited | Health & social care | 2007 |
| Amna Ul-Haq Limited | Real estate | 2014 |
| Amon Services Ltd | Construction | 2024 |
| Amonition Limited | Hospitality | 2023 |
| Amor of Life Ltd | Information & communication | 2010 |
| Amour Group Ltd | Wholesale & retail | 2016 |
| AMP Autos Ltd. | Wholesale & retail | 2013 |
| AMP2 Innovation CIC | Professional & scientific | 2025 |
| Ample Limited | Manufacturing | 1996 |
| Amplify Group Ltd. | Professional & scientific | 2016 |
| Amprex Tech Solution Limited | Information & communication | 2025 |
| AMPROPERTY1997 Ltd | Real estate | 2023 |
| Ampv Limited | Health & social care | 2016 |
| Amreet Ventures Ltd | Administrative & support | 2026 |
| Amrew Limited | Professional & scientific | 2007 |
| Amrin Malhi Ltd | Transport & logistics | 2021 |
| Amrit Courier Limited | Transport & logistics | 2025 |
| Amrit Groups Limited | Construction | 2025 |
| Amrit Sandhu Group Limited | Construction | 2025 |
| Amritsar Sweets & Catering Ltd | Wholesale & retail | 2020 |
| Amritsar Wale Production Ltd | Information & communication | 2022 |
| Amritsari Haweli Ltd | Hospitality | 2023 |