| Ambrit Kids Limited | Wholesale & retail | 2007 |
| Ambrose Healthcare (Holdings) Ltd | Professional & scientific | 2023 |
| Ambrose Healthcare Ltd | Professional & scientific | 2022 |
| AMC Energi Ltd | Construction | 2013 |
| AMC Exhibitions Limited | Manufacturing | 2012 |
| Amco Cambridge Limited | Wholesale & retail | 2025 |
| AMD 262A Ltd | Real estate | 2025 |
| AMD Asset Management Ltd | Real estate | 2017 |
| AMD Australia Ltd | Real estate | 2026 |
| AMD Windows Services Limited | Construction | 2025 |
| Amei General Trading Company Limited | Wholesale & retail | 2023 |
| Ameise Holding Company Limited | Financial services | 2024 |
| Amenuensis Ltd | Manufacturing | 2010 |
| Ameria Ltd | Information & communication | 2017 |
| American Penguin Limited | Other services | 2021 |
| Ames Asop Ltd | Real estate | 2017 |
| Amesbury Fleur Limited | Professional & scientific | 1997 |
| Amethyst Designs Limited | Manufacturing | 1981 |
| Amethyst Z. Ltd | Real estate | 2019 |
| AMG Composite Technologies Ltd | Professional & scientific | 2019 |
| Amgen Limited | Professional & scientific | 1989 |
| Amgen UK Holdings Limited | Professional & scientific | 2025 |
| AMH Components Ltd | Manufacturing | 2021 |
| Amhm Holdings Ltd | Information & communication | 2024 |
| Amicus Clinical Development Limited | Health & social care | 2022 |
| Amilon BIO Limited | Professional & scientific | 2025 |
| Amin Martial Arts Limited | Education | 2023 |
| Amino Communications Limited | Information & communication | 1998 |
| Amino Holdings Limited | Information & communication | 1996 |
| Amiraz Ltd | Real estate | 2014 |
| Amisan Cars Ltd | Transport & logistics | 2024 |
| AMK Bioconsulting Ltd | Professional & scientific | 2026 |
| Amkina Ltd | Hospitality | 2024 |
| AML Personnel Ltd | Administrative & support | 2023 |
| Amma Wellness Ltd | Real estate | 2023 |
| Ammaar Solutions Ltd | Information & communication | 2022 |
| Ammzz Ltd | Wholesale & retail | 2024 |
| Amoer Technology Co., Ltd | Wholesale & retail | 2022 |
| Amor Coffee Co Ltd | Hospitality | 2024 |
| Amor Training Ltd | Other services | 2018 |
| Amorphiq Ltd | Professional & scientific | 2025 |
| Amos & Sons Ltd | Real estate | 2025 |
| Amour Scientific Consulting Ltd | Professional & scientific | 2025 |
| AMP Advance Composites Ltd | Manufacturing | 2019 |
| AMP Management Limited | Real estate | 2018 |
| Ampag Developments Ltd | Real estate | 2025 |
| Ampashield Limited | Professional & scientific | 2020 |
| Amphista Therapeutics Limited | Professional & scientific | 2017 |
| Amphora Cambridge Limited | Wholesale & retail | 2022 |
| Ampkine Limited | Professional & scientific | 2019 |
| Amplifyforyou Ltd | Professional & scientific | 2023 |
| Amplitude & Phase Technologies Co., Ltd | Manufacturing | 2022 |
| AMR Abdelaal Limited | Health & social care | 2013 |
| Amrani Education Ltd | Education | 2011 |
| Amron (SA) Co., Ltd | Mining & quarrying | 2026 |
| Amsbio Holdings Limited | Health & social care | 2008 |
| Amtechnics Ltd | Manufacturing | 2025 |
| Amulet Ltd | Professional & scientific | 2025 |
| Amvmaintenance Ltd | Manufacturing | 2025 |
| Amwell Road Freehold Limited | Households | 2019 |
| AMY Thomson Limited | Manufacturing | 2020 |
| Amynishu Ltd | Real estate | 2019 |
| AMZ Cambridge Limited | Wholesale & retail | 2019 |
| AMZ Services Ltd | Manufacturing | 2018 |
| Amzbarley Trading Co., Ltd | Extraterritorial | 2019 |
| AN Electroo Ltd | Information & communication | 2021 |
| Anaero Technology Limited | Professional & scientific | 2013 |
| Anagallis Communications Ltd | Professional & scientific | 2016 |
| Anageo Limited | Real estate | 2020 |
| Anaire Ltd | Professional & scientific | 2025 |
| Analysis UK Limited | Professional & scientific | 2001 |
| Analyticscambridge Ltd | Information & communication | 2011 |
| Analytik Holdings Limited | Financial services | 2025 |
| Anamaxx Ltd | Manufacturing | 2026 |
| Ananta International Limited | Wholesale & retail | 2015 |
| ANAR5 Limited | Health & social care | 2022 |
| Anastasia Ahern Ltd. | Other services | 2007 |
| Anauel LLP | | 2004 |
| ANAYAH25 Ltd | Hospitality | 2025 |
| ANB Sensors Ltd | Professional & scientific | 2015 |
| Anbeca Limited | Real estate | 2006 |
| Anchor Thai Ltd | Hospitality | 2022 |
| Anchorage View Limited | Real estate | 2024 |
| Anchuan Technical Co., Ltd | Professional & scientific | 2016 |
| AND the Beat Goes on Ltd | Other services | 2026 |
| Andalusi Culture Ltd | Education | 2024 |
| Anderson Bespoke Construction Ltd | Construction | 2021 |
| Anderson Genomics Consultancy Ltd | Professional & scientific | 2020 |
| Anderson Laboratory | Information & communication | 2022 |
| Andersonnash Limited | Professional & scientific | 2007 |
| Andiny Limited | Transport & logistics | 2023 |
| Ando IT Ltd | Information & communication | 2018 |
| Ando-Property Ltd | Real estate | 2019 |
| Andrea Atzeni Limited | Arts & recreation | 2010 |
| Andrei BUN Ltd | Manufacturing | 2024 |
| Andrei Daniel Bogdan Ltd | Manufacturing | 2026 |
| Andrei Symy Ltd | Manufacturing | 2022 |
| Andrei Tirui Limited | Manufacturing | 2022 |
| ANDREI12 Ltd | Manufacturing | 2023 |
| Andreiunguru Ltd | Manufacturing | 2026 |