| AMB Enforcements Ltd | Construction | 2018 |
| Ambaafrikana Ltd | Manufacturing | 2026 |
| Ambassadors of Grace Ministries | Manufacturing | 2013 |
| Amber and Vine Ltd | Wholesale & retail | 2025 |
| Amber Flame Ltd | Information & communication | 2019 |
| Amber Homes (Property Investments) Limited | Real estate | 2021 |
| Ambuwell Transportation Ltd | Transport & logistics | 2025 |
| Amenthespartch Agents Limited | Wholesale & retail | 2022 |
| Amfashiontv Limited | Wholesale & retail | 2019 |
| Amfle Limited | Health & social care | 2025 |
| AMG of Bromley Ltd | Other services | 2017 |
| AMG of Hayes Ltd | Other services | 2021 |
| Amicus Property Investments Limited | Real estate | 2025 |
| Amisn UK Ltd | Wholesale & retail | 2016 |
| Amitsentech Ltd | Financial services | 2018 |
| AMJ Property Solutions Ltd | Real estate | 2021 |
| Amonev Ltd | Wholesale & retail | 2016 |
| Amory Estates Ltd | Real estate | 2024 |
| Amos and Rushbrook Limited | Wholesale & retail | 2004 |
| Amosca Enterprise Limited | Information & communication | 2006 |
| AMP Smile Studio Ltd | Health & social care | 2025 |
| Ampco Consulting Limited | Professional & scientific | 2015 |
| Amphibia (UK) Limited | Water & waste | 2001 |
| Amphibia Limited | Water & waste | 2025 |
| Ample Access Support Services Ltd | Administrative & support | 2018 |
| Amplifier Consulting Ltd | Professional & scientific | 2026 |
| Ampm D7B Ltd | Real estate | 2020 |
| AMS Delivery Ltd | Transport & logistics | 2025 |
| Amsell Group Limited | Wholesale & retail | 2015 |
| Amuche Ltd | Other services | 2023 |
| Amulinde Ltd | Information & communication | 2014 |
| Amwell House Ltd | Households | 2024 |
| Anahit Ltd | Health & social care | 2019 |
| Analog and Digital Solutions Limited | Professional & scientific | 2021 |
| Anand Collection Limited | Administrative & support | 2007 |
| Ananyaa Consulting Ltd | Information & communication | 2015 |
| Anathoth Property Development Limited | Construction | 2022 |
| Andak Limited | Hospitality | 2016 |
| Andali Communications Limited | Administrative & support | 2013 |
| Anderson Montrose Limited | Administrative & support | 2007 |
| Anderson Scott Ltd | Financial services | 2014 |
| Andi General Construction Ltd | Construction | 2019 |
| Andmark Limited | Households | 1995 |
| Andrade Consultancy Services Ltd | Professional & scientific | 2019 |
| Andralis Investments Limited | Administrative & support | 2024 |
| Andralis Property Limited | Administrative & support | 2024 |
| Andre Mattis Plumbing Services Ltd | Construction | 2021 |
| Andrei Cavalciuc Limited | Transport & logistics | 2025 |
| Andreou Property Management LLP | | 2019 |
| Andrew DAV Logistic Ltd | Transport & logistics | 2025 |
| Andrew J Patrick Limited | Information & communication | 2017 |
| Andrew Milne Property Maintenance Limited | Administrative & support | 2012 |
| Andrews Accountancy Limited | Professional & scientific | 2019 |
| Andrix Ltd | Wholesale & retail | 2025 |
| Andsam (2008) Limited | Wholesale & retail | 2008 |
| Andscape Design and Construction Ltd | Administrative & support | 2026 |
| Andy Grimshaw Photography Limited | Professional & scientific | 2002 |
| Andy Jackson Enterprises Limited | Information & communication | 2014 |
| Aneliya Dimitrova Ltd | Administrative & support | 2011 |
| Anenome Court RTM Company Limited | Households | 2023 |
| Anerley Park RTM Company Limited | Households | 2011 |
| Angel Security Systems Limited | Administrative & support | 2003 |
| Angel Wharf Management Limited | Real estate | 2006 |
| Angell Electrical Services Limited | Construction | 2021 |
| Anglo Continental Clock Company Limited | Wholesale & retail | 1971 |
| Anglocap Ltd | Information & communication | 2011 |
| ANI & DUT Property Ltd | Real estate | 2024 |
| Anicalls Private Ltd | Information & communication | 2016 |
| Anima Pizzeria Ltd | Hospitality | 2024 |
| Animal Careers Limited | Education | 2025 |
| Animal Ultrasound Association CIC | Professional & scientific | 2016 |
| Animatronics Ltd | Arts & recreation | 2019 |
| Anisak Limited | Real estate | 2023 |
| Aniworld Ltd | Wholesale & retail | 2011 |
| Ankit Patel Ltd | Construction | 2016 |
| Anna Chart Consulting Ltd | Education | 2023 |
| Anna Riccoboni Limited | Health & social care | 2018 |
| Annapurna Indian Restaurant Limited | Hospitality | 2023 |
| Anne Clarke Property Development Limited | Real estate | 2023 |
| Annjer Investments Ltd | Real estate | 2025 |
| ANT PR and Productions Limited | Other services | 2014 |
| Antares KGT Ltd | Professional & scientific | 2023 |
| Anthony P Norris Ltd | Arts & recreation | 2019 |
| Anthony Packer Limited | Administrative & support | 2011 |
| Anthony Washington Ltd | Wholesale & retail | 2026 |
| Anti Records Ltd | Information & communication | 2022 |
| Antigoni Ltd | Extraterritorial | 2025 |
| Antonia Stewart Limited | Construction | 2006 |
| Antonio Builder Ltd | Construction | 2024 |
| Anumerate Limited | Professional & scientific | 2014 |
| ANV UK Limited | Administrative & support | 2007 |
| AOB London Limited | Manufacturing | 2020 |
| APA Electrical Services Limited | Administrative & support | 2015 |
| APC Electrical Services (London) Limited | Construction | 2015 |
| APC Surveyors Limited | Professional & scientific | 2009 |
| Apex Asset Management Services Ltd | Real estate | 2025 |
| Apex BI Limited | Information & communication | 2022 |
| Apex Cloud Ltd | Information & communication | 2020 |
| Apex Construction London Ltd | Construction | 2017 |
| Apex Designs Corporation Ltd | Professional & scientific | 2011 |