| AM Sales Limited | Wholesale & retail | 2016 |
| AM Stay Services Ltd | Real estate | 2025 |
| AM Wood Solutions Ltd | Construction | 2019 |
| Amala Investments Limited | Real estate | 2020 |
| Amala Limited | Wholesale & retail | 2017 |
| Amaneo Investments Ltd | Real estate | 2024 |
| Amankwabis Care Ltd | Health & social care | 2026 |
| Amara Properties Ltd | Real estate | 2006 |
| Amari Technologies Limited | Information & communication | 2016 |
| Amavans Limited | Wholesale & retail | 2010 |
| Amazing Sound Limited | Professional & scientific | 2004 |
| Amazing Space (Essex) Ltd | Construction | 2015 |
| Amazingly Care Limited | Health & social care | 2023 |
| AMB BTL Limited | Real estate | 2021 |
| AMB Partners Limited | Professional & scientific | 2019 |
| Amberjet Enterprises Limited | Real estate | 1976 |
| Amberley Alternative Assets Limited | Extraterritorial | 2007 |
| Ambient Building Services Limited | Professional & scientific | 2008 |
| Ambient Electrical Services Limited | Construction | 2001 |
| Ambient Holdings UK Limited | Professional & scientific | 2007 |
| Ambitious Aardvark Limited | Real estate | 2017 |
| Ambrose Electronics Limited | Wholesale & retail | 2001 |
| AMC S Metals Ltd | Wholesale & retail | 2026 |
| AMD Aircraft Paint and Fabric Ltd | Manufacturing | 2014 |
| Amdhan Limited | Information & communication | 2026 |
| American Car Hire Limited | Administrative & support | 2014 |
| American Vehicle Services Limited | Wholesale & retail | 2018 |
| Amester Ltd | Financial services | 2011 |
| Amey Dock & Door Specialists Limited | Professional & scientific | 2023 |
| AMF Consultants Ltd | Professional & scientific | 2018 |
| AMG Group of Companies Ltd | Wholesale & retail | 2018 |
| Amherst Business Limited | Professional & scientific | 2012 |
| Ami's Deli Limited | Hospitality | 2021 |
| Amie Limited | Health & social care | 2018 |
| Amir Express Limited | Administrative & support | 2025 |
| Amistad Holdings Limited | Real estate | 2025 |
| Amit Medical & Consultancy Ltd | Health & social care | 2017 |
| Amixis Services Limited | Information & communication | 2023 |
| Amjd Multiservices UK Limited | Health & social care | 2018 |
| AMM (Essex) Ltd | Construction | 2024 |
| Ammar & Sons Ltd | Real estate | 2025 |
| Ammar Holdings Ltd | Real estate | 2025 |
| Ammie Ltd | Construction | 2025 |
| Amora Designs Limited | Construction | 2021 |
| Amoreau Holdings Limited | Financial services | 2024 |
| Amphibion Limited | Professional & scientific | 2022 |
| Amphitrite Limited | Professional & scientific | 2020 |
| Ample Electrical Services Limited | Construction | 2022 |
| Ample Storage Company Limited | Real estate | 2025 |
| Amradaki Ltd | Hospitality | 2019 |
| AMS Air Conditioning Limited | Energy | 2016 |
| AMS Plastic Surgery Ltd | Health & social care | 2013 |
| Amtek Limited | Professional & scientific | 1988 |
| AMTM4 Limited | Real estate | 2025 |
| Amtol Limited | Professional & scientific | 2017 |
| AMY Beager Limited | Arts & recreation | 2022 |
| AMY Davids Events Ltd | Professional & scientific | 2021 |
| AMY MAY Trust Enterprises Limited | Administrative & support | 2019 |
| Amy's Rainbow Candles Ltd | Health & social care | 2015 |
| Amyhouse Premier Limited | Real estate | 2023 |
| AN Angel at My Table Limited | Wholesale & retail | 1997 |
| AN M&C Services Ltd | Real estate | 2021 |
| Anais Capital Ltd | Professional & scientific | 2025 |
| Anaisa Services Ltd | Health & social care | 2021 |
| Analoga Ltd | Information & communication | 2017 |
| Analytic Advantage Ltd | Professional & scientific | 2025 |
| Analytical QMS Ltd | Professional & scientific | 2025 |
| Ananthi Naveen RAJ Ltd | Real estate | 2025 |
| Ananya Creations Ltd | Information & communication | 2024 |
| Ananya Technologies Limited | Information & communication | 2014 |
| Anayah Jewellery Ltd. | Wholesale & retail | 2017 |
| ANC Construction Limited | Construction | 2019 |
| ANC Villas Limited | Real estate | 2020 |
| Anchor Community Provision CIC | Financial services | 2025 |
| Anchor Street Care Limited | Real estate | 2018 |
| Ancomi Trans Ltd | Transport & logistics | 2018 |
| Anderson Design & Build Limited | Construction | 2003 |
| Anderson Development Group Limited | Financial services | 2023 |
| Anderson Developments Limited | Real estate | 2007 |
| Anderson Estates Management Limited | Households | 2003 |
| Anderson Graphic Limited | Other services | 2008 |
| Anderson Group Properties Limited | Real estate | 2004 |
| Anderson Group Services Limited | Professional & scientific | 2000 |
| Anderson O&U Limited | Real estate | 2017 |
| Andica International Limited | Construction | 2005 |
| Andler Limited | Hospitality | 2015 |
| Andras Mede Ltd | Transport & logistics | 2019 |
| Andrew Davison Architects Limited | Professional & scientific | 2014 |
| Andrew DOY Servs & Co Ltd | Information & communication | 2026 |
| Andrew Grima Limited | Extraterritorial | 2017 |
| Andrew Holdstock Design Limited | Professional & scientific | 2012 |
| Andrew Kent Agencies Ltd | Manufacturing | 2007 |
| Andrew Reid Services Limited | Professional & scientific | 2020 |
| Andrew Street Properties Limited | Real estate | 2003 |
| Andrew's Whirlybirds Ltd | Administrative & support | 2021 |
| Andrewsfield Air Operations Limited | Other services | 1993 |
| Andrian 1 Ltd | Construction | 2026 |
| Andun Engineering Consultants Ltd | Construction | 2019 |
| Andy Elliott Limited | Real estate | 2003 |
| Anevero Limited | Wholesale & retail | 2022 |