| Aspiros Arts Ltd | Wholesale & retail | 2018 |
| Asplin Consultants (Cambridge) Limited | Professional & scientific | 2018 |
| Asplins Limited | Professional & scientific | 2015 |
| Aspuna Group Limited | Financial services | 2016 |
| Asquared Padel Ltd | Arts & recreation | 2025 |
| Asre Co., Ltd | Extraterritorial | 2023 |
| Asselin Limited | Wholesale & retail | 2023 |
| Assent Trade PVT Ltd | Wholesale & retail | 2025 |
| Asset Hedging Ltd | Administrative & support | 2024 |
| Asseti Ltd | Professional & scientific | 2024 |
| Assisi Properties Ltd | Real estate | 2020 |
| Assk Barry LLP | | 2011 |
| Associate Decorators Limited | Construction | 2004 |
| Associated British Engineering PLC | Professional & scientific | 1910 |
| Association for Cultural Exchange Limited(The) | Education | 1958 |
| Association of British Chinese Professors | Other services | 2018 |
| AST Global Recruiters Ltd | Administrative & support | 2025 |
| Asta Aeronautic Support Ltd | Manufacturing | 2024 |
| Astana Limited | Hospitality | 2020 |
| Astellas Engineered Small Molecules U.K. Limited | Professional & scientific | 2012 |
| Aster Pharmed Ltd | Wholesale & retail | 2021 |
| Astex Therapeutics Limited | Professional & scientific | 1999 |
| Asthasoulspeak Ltd | Other services | 2024 |
| Astles Control Systems Limited | Manufacturing | 1990 |
| Aston Howden Group Limited | Manufacturing | 2022 |
| Aston London Campus Limited | Education | 2025 |
| Astra Jewelry Ltd | Manufacturing | 2024 |
| Astra Pharmaceuticals Limited | Professional & scientific | 1908 |
| Astracon Limited | Professional & scientific | 2000 |
| Astral Dawn Studios Ltd | Information & communication | 2019 |
| Astralis Digital Ltd | Information & communication | 2025 |
| Astralis Galaxy Ltd | Wholesale & retail | 2026 |
| Astranet Systems (Cambridge) Ltd | Manufacturing | 2018 |
| Astrapharm | Professional & scientific | 1953 |
| Astrazeneca Death in Service Trustee Limited | Professional & scientific | 2001 |
| Astrazeneca Employee Share Trust Limited | Administrative & support | 1994 |
| Astrazeneca Finance Limited | Financial services | 1992 |
| Astrazeneca Intermediate Holdings Limited | Administrative & support | 2007 |
| Astrazeneca Investments Limited | Professional & scientific | 1992 |
| Astrazeneca Japan Limited | Professional & scientific | 2000 |
| Astrazeneca Nominees Limited | Professional & scientific | 1992 |
| Astrazeneca Pensions Trustee Limited | Administrative & support | 1993 |
| Astrazeneca PLC | Manufacturing | 1992 |
| Astrazeneca Quest Limited | Administrative & support | 1994 |
| Astrazeneca Share Trust Limited | Administrative & support | 1994 |
| Astrazeneca Sweden Investments Limited | Administrative & support | 2003 |
| Astrazeneca Treasury Limited | Professional & scientific | 1994 |
| Astrazeneca UK Limited | Professional & scientific | 1998 |
| Astrazeneca US Investments Limited | Administrative & support | 2002 |
| Astrd One Ltd | Information & communication | 2025 |
| Astrea Bioseparations Ltd. | Professional & scientific | 1987 |
| Astrea Group Holdings Company Limited | Financial services | 2020 |
| Astrion Informatics Ltd | Manufacturing | 2025 |
| Astro Bidco Limited | Financial services | 2018 |
| Astrofarhi Technik Ltd | Manufacturing | 2024 |
| Astrophe UK Ltd | Financial services | 2025 |
| Astroshader Limited | Information & communication | 2024 |
| Astrovista Ltd | Information & communication | 2022 |
| Astrum Trading Ltd | Wholesale & retail | 2025 |
| Astute Devices Limited | Manufacturing | 2026 |
| Asubuhi Limited | Professional & scientific | 2025 |
| Asuuta Limited | Professional & scientific | 2011 |
| ASW Property Investment Limited | Real estate | 2018 |
| Asya Food Services Limited | Hospitality | 2018 |
| Asylum Hair Design Limited | Other services | 2018 |
| AT Angling Products Ltd | Wholesale & retail | 2024 |
| AT Auto Centre Limited | Wholesale & retail | 2025 |
| AT NO.1 Limited | Financial services | 2021 |
| AT Number 6 Limited | Real estate | 2020 |
| AT Traffic Management Ltd | Construction | 2023 |
| Atabani Consulting Limited | Professional & scientific | 2019 |
| Ataksak International Limited | Extraterritorial | 2022 |
| Atamai Labs Ltd | Information & communication | 2019 |
| ATC Equestrian Ltd | Agriculture & fishing | 2023 |
| ATE Testing Service Ltd. | Extraterritorial | 2016 |
| Atelier Brown Ltd | Professional & scientific | 2022 |
| Atelier Education Limited | Education | 2022 |
| Atelier Elborne Ltd | Professional & scientific | 2019 |
| Atentfly Ltd | Manufacturing | 2026 |
| Atheana Investments Ltd | Real estate | 2020 |
| Atheena Boutique Limited | Wholesale & retail | 2023 |
| Athena (M1/M2) Block Management Company Limited | Real estate | 2018 |
| Athena Business Education Limited | Education | 2022 |
| Athena DOM Holdings Ltd | Real estate | 2024 |
| Athena IT Consulting Ltd | Information & communication | 2024 |
| Athenophilia Ltd | Information & communication | 2019 |
| Athey Consulting Limited | Professional & scientific | 2011 |
| Athish Food & Wine Ltd | Wholesale & retail | 2024 |
| Athlete Longevity Ltd | Professional & scientific | 2025 |
| Athleticare Systems Limited | Health & social care | 2024 |
| Athlo.Ai Ltd | Information & communication | 2025 |
| Atik Cameras Limited | Manufacturing | 2006 |
| Atilla Composites Ltd | Manufacturing | 2026 |
| Atitos Ltd | Construction | 2017 |
| Ativest Ltd | Professional & scientific | 2022 |
| ATJ Consultants Ltd | Information & communication | 2025 |
| ATK Composites Ltd | Manufacturing | 2024 |
| Atlanti (UK) Limited | Professional & scientific | 2011 |
| Atlantic Style Group Limited | Wholesale & retail | 2017 |
| Atlanticomnium (UK) Limited | Financial services | 2011 |