| Asquith Avenue Ltd | Real estate | 2025 |
| ASR Supplies Ltd | Wholesale & retail | 2022 |
| Asra Educationss Ltd | Education | 2025 |
| Assaygen Limited | Professional & scientific | 2026 |
| Assentar Limited | Professional & scientific | 2013 |
| Assess 4 Success Tuition Ltd | Education | 2020 |
| Assessed Education Limited | Education | 2010 |
| Asset & Vehicle Management Limited | Financial services | 2020 |
| Asset Bookkeeping Ltd | Professional & scientific | 2023 |
| Asset Intelligence Holdings Limited | Information & communication | 2024 |
| Assets & Compliance Managed Services Ltd | Professional & scientific | 2003 |
| Assetview Limited | Extraterritorial | 2022 |
| Assiduous Technologies Limited | Professional & scientific | 2018 |
| Assist 7 Days Ltd | Health & social care | 2016 |
| Assisted Health & Mobility Limited | Wholesale & retail | 2011 |
| Assistive Bathing Limited | Administrative & support | 2001 |
| Association of Apprentices | Education | 2019 |
| Association of Personal Injury Lawyers | Other services | 1994 |
| Assumpta Care Limited | Health & social care | 2022 |
| Assure YOU Ltd | Professional & scientific | 2026 |
| Assured Build and Maintain Ltd | Construction | 2022 |
| Assured Career Training Ltd | Education | 2022 |
| Assured Professionals Limited | Health & social care | 2015 |
| Assured Property Investment Partnership Ltd | Real estate | 2024 |
| Assured Reactive Maintenance Limited | Construction | 2017 |
| Assured Source Limited | Wholesale & retail | 2017 |
| Assured Surfacing and Construction Ltd | Construction | 2024 |
| AST Auto Centre Ltd | Wholesale & retail | 2022 |
| AST Developments Ltd | Construction | 2025 |
| AST Innovations Limited | Extraterritorial | 2014 |
| AST Language Services Ltd | Professional & scientific | 2000 |
| AST7 Limited | Information & communication | 2026 |
| Astell Solutions Ltd | Information & communication | 2016 |
| Asterid Ltd | Real estate | 2024 |
| Astill Homes Ltd | Construction | 2018 |
| Astogna Limited | Real estate | 2019 |
| Astolinks International Ltd | Information & communication | 2023 |
| Aston Berkeley Estates Limited | Real estate | 2013 |
| Aston Cranswick Limited | Administrative & support | 2018 |
| Aston Venture Limited | Wholesale & retail | 2002 |
| Astoncrest Limited | Other services | 2023 |
| Astonia Consultancy Ltd | Wholesale & retail | 2017 |
| Astons General Commercial Appliance Sales and Repairs Limited | Wholesale & retail | 2012 |
| Astoria Bingo Club Limited | Arts & recreation | 1955 |
| Astra DDB Trading Limited | Transport & logistics | 2024 |
| Astra Developments Limited | Construction | 2006 |
| Astra Wealth Limited | Financial services | 2024 |
| Astral Accounts Ltd | Professional & scientific | 2022 |
| Astral Grove Management Ltd | Extraterritorial | 2011 |
| Astralite Limited | Financial services | 1961 |
| Astram Limited | Extraterritorial | 2009 |
| Astram Solutions Limited | Extraterritorial | 2008 |
| Astran Limited | Extraterritorial | 2009 |
| Astrelle Insurance Services Limited | Financial services | 1987 |
| Astrid Home Improvements Ltd | Construction | 2026 |
| Astridea Investments Ltd | Real estate | 2026 |
| Astrimmune Ltd | Professional & scientific | 2011 |
| Astro Holdings Limited | Professional & scientific | 2015 |
| Astro Investments Limited | Real estate | 2017 |
| Astro Kings Ltd | Arts & recreation | 2015 |
| Astro Piping Engineers Limited | Professional & scientific | 2020 |
| Astron International PVT Ltd | Hospitality | 2023 |
| Astrum Recruitment Limited | Administrative & support | 2020 |
| Astute Business Thinking Limited | Professional & scientific | 2021 |
| Astute Courses Ltd | Education | 2017 |
| Astute Housing Limited | Real estate | 2021 |
| Astute Worx Ltd | Professional & scientific | 2025 |
| Asuman Group Ltd | Hospitality | 2025 |
| Asuman Properties Ltd | Real estate | 2022 |
| Asuria People Services (UK) Limited | Administrative & support | 2020 |
| Asus Technologies Limited | Other services | 2014 |
| Asvit Services Limited | Information & communication | 2019 |
| Asvr Properties Limited | Real estate | 2019 |
| ASW Properties (East Midlands) LLP | | 2007 |
| Asya Pelin Ltd | Wholesale & retail | 2020 |
| AT Building & Property Services Limited | Real estate | 2025 |
| AT Counselling Limited | Health & social care | 2022 |
| AT Medical Aesthetics & Co Limited | Health & social care | 2022 |
| AT One With Nature Ltd | Professional & scientific | 2024 |
| AT Oral Care Ltd | Health & social care | 2025 |
| AT Secmed Ltd | Administrative & support | 2021 |
| AT Transportation Ltd | Transport & logistics | 2024 |
| AT Trends Limited | Wholesale & retail | 2024 |
| AT Your Care Health Ltd | Other services | 2017 |
| AT2 Tree Surgery Limited | Real estate | 2014 |
| Atasami Ltd | Construction | 2026 |
| ATC (Nottm) Ltd | Health & social care | 2025 |
| ATC Verita Ltd | Hospitality | 2017 |
| Atcham Services Ltd | Professional & scientific | 2023 |
| ATE Bakes Ltd | Manufacturing | 2025 |
| Ateeyah Limited | Real estate | 2026 |
| Atelier Living Ltd | Real estate | 2022 |
| Ateliernoir Hair Ltd | Other services | 2026 |
| Atellar Consultancy Limited | Information & communication | 2020 |
| Ates Offlicence Limited | Wholesale & retail | 2018 |
| ATF Holdings Ltd | Real estate | 2020 |
| ATF Signs Ltd | Construction | 2024 |
| Athavan Property Limited | Real estate | 2018 |
| Atheesha Trade Limited | Wholesale & retail | 2026 |
| Athena Concrete Pumping Ltd | Construction | 2025 |