| Askivy Ltd | Information & communication | 2013 |
| Askksa Limited | Wholesale & retail | 2006 |
| Askwebsmith Ltd | Construction | 2026 |
| ASL Global Ltd | Wholesale & retail | 2025 |
| ASL International Ventures Ltd | Education | 2025 |
| ASL Procurement Ltd | Professional & scientific | 2022 |
| Aslam Bhai Ltd | Wholesale & retail | 2025 |
| Aslamjavaid Ltd | Wholesale & retail | 2025 |
| Aslan 2026 Ltd | Hospitality | 2026 |
| Asli Ingec Ltd | Wholesale & retail | 2026 |
| Asli Limited | Wholesale & retail | 2025 |
| Asma for Software and Marketing Ltd | Information & communication | 2022 |
| Asmx Services Limited | Information & communication | 2015 |
| ASO & Balen Ltd | Wholesale & retail | 2025 |
| ASO Management Ltd | Administrative & support | 2016 |
| Asortedhome Ltd | Administrative & support | 2026 |
| ASP Architectural Limited | Administrative & support | 1989 |
| ASP Collect Ltd | Construction | 2026 |
| Aspcet Design BIM Solutions Limited | Construction | 2019 |
| Aspec Building Ltd | Construction | 2022 |
| Aspect Logistics Ltd | Transport & logistics | 2017 |
| Aspects Inspire Ltd | Information & communication | 2012 |
| Aspeni Group Limited | Real estate | 2018 |
| Asper Enterprises Limited | Wholesale & retail | 2021 |
| Aspiraflows Ltd | Information & communication | 2026 |
| Aspiration Experts Ltd | Professional & scientific | 2025 |
| Aspire & Radiant Limited | Wholesale & retail | 2025 |
| Aspire Adventure Limited | Arts & recreation | 2013 |
| Aspire Consult Ltd | Professional & scientific | 2024 |
| Aspire Energy Group Ltd | Construction | 2019 |
| Aspire Fitness (Wales) Limited | Arts & recreation | 2004 |
| Aspire Horizon Homes Ltd | Real estate | 2025 |
| Aspire International Tutors Ltd | Education | 2016 |
| Aspire Letting Investments Limited | Real estate | 2016 |
| Aspire Running Events Limited | Arts & recreation | 2014 |
| Aspire Systems Digital Solutions Ltd. | Information & communication | 2005 |
| Aspire Tours Limited | Administrative & support | 2024 |
| Aspire Wave Ltd | Wholesale & retail | 2025 |
| Aspiro Research and Development LLP | | 2012 |
| Aspius Ltd | Construction | 2014 |
| Aspksp Property Ltd | Real estate | 2026 |
| ASQ Cardiff Ltd | Wholesale & retail | 2026 |
| ASR Consultants Ltd | Professional & scientific | 2019 |
| ASR Healthcare Limited | Health & social care | 2017 |
| Asra Construction Ltd | Construction | 2026 |
| Asra Developments Ltd | Real estate | 2026 |
| Asra Gaphic & IT Solutions Ltd | Information & communication | 2025 |
| Asra Transport Ltd | Transport & logistics | 2026 |
| Asrfwel Mart Ltd | Wholesale & retail | 2025 |
| Assadaqaat Community Finance | Financial services | 2017 |
| Assata Doumbia Ltd | Wholesale & retail | 2025 |
| Assembly 100 LLP | | 2021 |
| Assero Security Operations Ltd | Administrative & support | 2022 |
| Assero Security Services Limited | Administrative & support | 2020 |
| Assero Training Solutions Limited | Education | 2023 |
| Assertive Assimilation Ltd | Professional & scientific | 2014 |
| Assess Audit Assure Limited | Professional & scientific | 2021 |
| Asset Backed Management Limited | Administrative & support | 2017 |
| Asset Excel Ltd | Other services | 2018 |
| Asset Management Solutions Limited | Professional & scientific | 2000 |
| Assetcore Holdings Ltd | Financial services | 2025 |
| Assetproc Limited | Professional & scientific | 2018 |
| Assets 365 Limited | Information & communication | 2020 |
| Assetseeds Ltd | Financial services | 2020 |
| Assi Cafe Limited | Hospitality | 2019 |
| Assiduous Electrical Installations Limited | Manufacturing | 2018 |
| Assigntake Property Management Limited | Households | 1992 |
| Assist Heat Care UK Ltd | Construction | 2011 |
| Assist&Security Ltd | Other services | 2017 |
| Assisted Homecare Ltd | Health & social care | 2021 |
| Assn UK Ltd | Hospitality | 2025 |
| Asso Developments Ltd | Real estate | 2021 |
| Associated Community Training Limited | Education | 1988 |
| Associated Legal Firm & Partners Ltd. | Professional & scientific | 2019 |
| Associated Sales Agencies Limited | | 1946 |
| Associated Western Limited | Manufacturing | 1947 |
| Association of British Nigeria Councillors UK Limited | Public administration | 2020 |
| Assos Catering Limited | Hospitality | 2019 |
| Assos Kitchen Ltd | Manufacturing | 2024 |
| Assura Homes Ltd | Hospitality | 2025 |
| Assure GAS Ltd | Construction | 2022 |
| Assured Building Solutions Ltd | Construction | 2019 |
| Assured Care Ltd | Health & social care | 2017 |
| Assured Consulting Limited | Information & communication | 2024 |
| Assured Data Services Ltd | Information & communication | 2019 |
| Assured Heating Solutions Ltd | Construction | 2009 |
| AST Enterprises Ltd | Wholesale & retail | 2025 |
| AST Holdings PVT. Ltd | Real estate | 2024 |
| Asta Developments Limited | Real estate | 1997 |
| Astarex Limited | Transport & logistics | 2005 |
| Astario Systems Ltd | Information & communication | 2018 |
| Astega Partnerships Ltd | Construction | 2022 |
| Astell Group Limited | Wholesale & retail | 2026 |
| Aster Property Solutions Ltd | Real estate | 2024 |
| Asterism Consulting Limited | Information & communication | 2014 |
| Astero Digital Ltd | Information & communication | 2024 |
| Asteroid Accountancy Ltd | Professional & scientific | 2023 |
| Asters Management Ltd | Real estate | 2025 |
| Asteys Management Limited | Health & social care | 2021 |
| Asth & Funkti Limited | Financial services | 2020 |