| Asian House Limited | Hospitality | 2025 |
| Asian Resource Centre of Croydon Limited | Other services | 2007 |
| Asiana Spice (BD) Ltd | Hospitality | 2019 |
| Asiatrd Ltd | Wholesale & retail | 2023 |
| Asiko Ltd | Wholesale & retail | 2019 |
| ASJ Accommodations Limited | Real estate | 2017 |
| ASJ Risk Consulting Ltd | Professional & scientific | 2020 |
| ASK Cars Gatwick Ltd | Transport & logistics | 2022 |
| ASK Food &Wine Ltd | Wholesale & retail | 2022 |
| ASK Surfaces Limited | Administrative & support | 2024 |
| ASK Talent Limited | Administrative & support | 2026 |
| ASK UK Accountancy Ltd | Professional & scientific | 2021 |
| ASK US Consultancy Limited | Administrative & support | 2024 |
| Askern Road News Limited | Wholesale & retail | 2009 |
| Askr Entertainment Ltd | Health & social care | 2022 |
| ASL Contracting Ltd | Construction | 2024 |
| ASL Monitoring Limited | Administrative & support | 2026 |
| Aslami Services Ltd | Transport & logistics | 2024 |
| Asma Lebanese Food Ltd | Hospitality | 2025 |
| Asokan Construction Ltd | Construction | 2019 |
| Aspec Precision Engineering Limited | Manufacturing | 2001 |
| Aspect (the Atrium) Management Limited | Households | 2008 |
| Aspect Bespoke Engineering Limited | Manufacturing | 2009 |
| Aspect Coffee Ltd | Manufacturing | 2025 |
| Aspect Joinery Specialists Limited | Construction | 2017 |
| Aspect Living (Management) Ltd | Real estate | 2023 |
| Aspect Living (the Glade) Limited | Real estate | 2022 |
| Aspect Spirituel Ltd | Administrative & support | 2017 |
| Aspen Lodge Management Company Limited | Households | 1997 |
| Aspex Group Limited | Construction | 2022 |
| Aspire to Better Ltd | Professional & scientific | 2026 |
| Aspire Youth Academy CIC | Education | 2025 |
| Aspley Homes Building Services Limited | Construction | 2003 |
| Aspro Consultants Ltd | Information & communication | 2026 |
| ASQ Transport Ltd | Transport & logistics | 2020 |
| Assag Hill Ltd | Administrative & support | 2016 |
| Assaisonnement Yiaya Ltd | Manufacturing | 2025 |
| Asset Loan Management Limited | Financial services | 2018 |
| Asset Management Solutions (AMS) Ltd | Real estate | 2018 |
| Asset Property & Finance Ltd | Construction | 2018 |
| Assetrise Properties Ltd | Real estate | 2025 |
| Assets Alliance London Ltd | Real estate | 2019 |
| Assigndate Property Management Limited | Households | 1992 |
| Assistance Technique International (A.T.I.) Ltd | Administrative & support | 2007 |
| Assistfirst Ltd | Administrative & support | 2025 |
| Associated Access Control Ltd | Administrative & support | 1991 |
| Associated Cctv Systems Limited | Administrative & support | 1975 |
| Associated Lock Services Limited | Administrative & support | 1973 |
| Associated Safe Company Limited | Administrative & support | 1970 |
| Associated Security Alarms Limited | Administrative & support | 1972 |
| Associated Security Grilles Limited | Administrative & support | 1976 |
| Associated Security Group Limited | Administrative & support | 1975 |
| Associated Steel Window Services Limited | Construction | 1994 |
| Associates Healthcare Community Interest Company | Health & social care | 2018 |
| Associates of Eden Limited | Hospitality | 2023 |
| Association of Solicitor Notaries in Greater London | Other services | 1985 |
| Assosciation of Ayurveda Academy CIC | Education | 2020 |
| Assurance Care Services Limited | Health & social care | 2010 |
| Assured Priority Care Limited | Health & social care | 2020 |
| AST Design & Advertising Limited | Professional & scientific | 1997 |
| AST Media Limited | Professional & scientific | 2017 |
| AST Repairs Limited | Construction | 2023 |
| AST Scaffolding Limited | Construction | 2019 |
| Astia Group Limited | Manufacturing | 2024 |
| Astika Limited | Professional & scientific | 2015 |
| Astl Limited | Manufacturing | 2026 |
| Astley Green Management Company Limited | Households | 2015 |
| Aston Pearl Accountants Ltd | Professional & scientific | 2021 |
| Aston Pearl Limited | Real estate | 2017 |
| Aston Road Development Ltd | Real estate | 2020 |
| Astor Grange Management Company Ltd | Households | 2021 |
| Astra Catering Limited | | 1983 |
| Astralounge.Ca Limited | Wholesale & retail | 2025 |
| Astridp Coaching and Training Services Limited | Education | 2022 |
| Astro Martin Ltd | Education | 2013 |
| Astrono International Limited | Wholesale & retail | 2023 |
| Astrosoccer 4 U Ltd | Arts & recreation | 2003 |
| Astv Media Ltd | Information & communication | 2022 |
| Astwood Property Limited | Real estate | 2020 |
| Aswan Tech Ltd | Information & communication | 2025 |
| AT & KT Limited | Hospitality | 2025 |
| AT Design Studio Ltd | Professional & scientific | 2025 |
| AT Energy (UK) Limited | Administrative & support | 2010 |
| AT Gems Ltd | Wholesale & retail | 2023 |
| AT Securities Limited | Real estate | 2015 |
| ATA SUÉ Ltd | Manufacturing | 2025 |
| Atalanta Construction Ltd | Real estate | 2013 |
| Atalanta Services Ltd | Transport & logistics | 2022 |
| Atarah Properties Ltd | Real estate | 2025 |
| ATB Professionals Limited | Real estate | 2024 |
| Atelier AVO LLP | | 2016 |
| Atelier DEL Vino UK Ltd | Wholesale & retail | 2024 |
| Atelier Vero Limited | Manufacturing | 2025 |
| Atene En-Suite Rooms Ltd | Hospitality | 2019 |
| ATF Construction Ltd | Construction | 2015 |
| ATF Property Investment Ltd | Real estate | 2023 |
| Atfr Construction Ltd | Construction | 2024 |
| Atgs Homes Ltd | Real estate | 2025 |
| Athena CDM Limited | Construction | 2006 |
| Athena Court Limited | Households | 1988 |