| Arrow Asset Management Ltd | Professional & scientific | 2015 |
| Arrow Electrical & Plumbing Services Limited | Construction | 2003 |
| Arrow Rider Training Limited | Education | 1998 |
| Art of Dental Care Limited | Health & social care | 2023 |
| Art Trading Solutions Ltd | Arts & recreation | 2019 |
| Artell Interior Design Ltd | Wholesale & retail | 2007 |
| Artemis Cleaning Services Ltd | Hospitality | 2025 |
| Artemis Contractor Supply Chain Management Limited | Professional & scientific | 2022 |
| Artham Properties Ltd | Real estate | 2019 |
| Arthingdale Limited | Financial services | 2020 |
| Arthur-Witter Projects Ltd | Other services | 2014 |
| Aryama Consulting Limited | Information & communication | 2012 |
| AS Global Consultancy Ltd | Professional & scientific | 2022 |
| Ascot House Harrogate Limited | Hospitality | 2025 |
| Asdmh Ltd | Hospitality | 2026 |
| Asgr Construction Ltd | Construction | 2026 |
| ASH Grove Ltd | Real estate | 2019 |
| Ashbery Associates Ltd | Information & communication | 2019 |
| Ashey Medical Ltd | Health & social care | 2022 |
| Ashley Green (Sale) Residents Association Limited | Households | 2003 |
| Ashley Law Wealth Management Ltd | Financial services | 2018 |
| Ashley Murray Limited | Professional & scientific | 2015 |
| Ashmore Acoustics Ltd | Administrative & support | 2009 |
| Ashorus Limited | Real estate | 2024 |
| Ashton & Grosvenor Limited | Real estate | 2010 |
| Ashton Hayes Sports and Recreation Association | Arts & recreation | 2009 |
| Ashton Maund Associates Limited | Administrative & support | 1994 |
| Ashton, Mouldsworth & Horton CUM Peel Village Hall Charitable Company Limited | Other services | 2020 |
| Ashtum Ventures Limited | Hospitality | 2020 |
| Ashtvinayak Limited | Wholesale & retail | 2021 |
| Ashwood Commercial Limited | Real estate | 2017 |
| Ashwood Farm Court Management Company Limited | Real estate | 1998 |
| Ashwood Retail Limited | Professional & scientific | 2023 |
| Ashworth Autos Ltd | Wholesale & retail | 2025 |
| Ashworth Brothers Limited | Construction | 1953 |
| ASI Meat Ltd | Wholesale & retail | 2025 |
| Asia Europe Group Ltd | Manufacturing | 2019 |
| ASK About Ltd | Administrative & support | 2019 |
| Askari Projects Ltd | Construction | 2015 |
| Aslan Business Limited | Wholesale & retail | 2026 |
| Asonja Estates Limited | Real estate | 2020 |
| ASP Property Holdings Limited | Real estate | 2018 |
| Aspection Ltd | Information & communication | 2016 |
| Asper Group Ltd | Construction | 2026 |
| Aspirations Enterprise Ltd | Wholesale & retail | 2019 |
| Aspire 2 Inspire People Ltd | Professional & scientific | 2021 |
| Aspire Assessments Ltd | Health & social care | 2023 |
| Aspire Commerce Group Limited | Financial services | 2021 |
| Aspire Healthcare Solutions Ltd | Public administration | 2021 |
| Aspire Lending (1) Limited | Financial services | 2024 |
| Aspire Lending (2) Limited | Financial services | 2024 |
| Aspire Lending (3) Limited | Financial services | 2025 |
| Aspire Lending (4) Limited | Financial services | 2025 |
| Aspire Lending (5) Limited | Financial services | 2026 |
| Aspire Lending Limited | Financial services | 2024 |
| Aspire Nutrition and Dietetic Limited | Administrative & support | 2017 |
| Aspire Payments Limited | Financial services | 2015 |
| Aspire Student Living Gloucester Limited | Administrative & support | 2017 |
| Aspire Student Living Group Limited | Administrative & support | 2024 |
| Aspire Student Living Hartpury Limited | Administrative & support | 2019 |
| Aspire Student Living Hereford NO.1 Limited | Administrative & support | 2019 |
| Aspire Student Living Hereford NO.2 Limited | Administrative & support | 2019 |
| Aspire Students Limited | Extraterritorial | 2018 |
| Aspritch Properties Limited | Real estate | 2012 |
| Assertthat Limited | Information & communication | 2019 |
| Asset Finance N.I. Ltd | Financial services | 2017 |
| Asset Fire Solutions Limited | Public administration | 2019 |
| Associated Alarms Ltd | Other services | 2022 |
| Association of Professional Declutterers and Organisers | Other services | 2022 |
| Association of Sign Language Interpreters | Other services | 2003 |
| Assum Limited | Financial services | 2022 |
| Assure Financial Advisory Limited | Professional & scientific | 2023 |
| AST808 Limited | Hospitality | 2026 |
| Astala Skincare Limited | Extraterritorial | 2020 |
| Aster Ventures Limited | Financial services | 2021 |
| Astle Planning and Design Limited | Professional & scientific | 2005 |
| Astm Access Ltd | Professional & scientific | 2026 |
| Aston Jones Limited | Wholesale & retail | 2003 |
| Astor Group Ltd | Construction | 2018 |
| Astral Innovations Ltd | Construction | 2024 |
| Astron Trade Ltd | Wholesale & retail | 2025 |
| Astrospray Limited | Wholesale & retail | 2017 |
| Astute Development Consulting Limited | Professional & scientific | 2015 |
| Astute Private Wealth Management Limited | Financial services | 2024 |
| ASZ88 Ltd | Wholesale & retail | 2024 |
| AT Worldwide Ltd | Arts & recreation | 2026 |
| Atbt Ltd | Real estate | 2024 |
| Atdr Ltd | Real estate | 2021 |
| Atelier Arcangel Limited | Wholesale & retail | 2006 |
| Atev 1 Haulage Ltd | Transport & logistics | 2016 |
| ATGB1 Limited | Real estate | 2026 |
| Athena Portfolio Management Ltd | Real estate | 2020 |
| Atherform Limited | Professional & scientific | 1998 |
| Atkin Jones Limited | Professional & scientific | 2016 |
| Atkins Design & Construction Limited | Construction | 2025 |
| Atkins Group Holdings Limited | Construction | 2021 |
| Atkinson Accounts Ltd | Professional & scientific | 2012 |
| Atlas Flat Roofing Limited | Construction | 2025 |
| Atomic VPS Ltd | Information & communication | 2011 |
| Atort Associates Limited | Professional & scientific | 2019 |