| ANN Jackman Interiors Limited | Construction | 2009 |
| ANN Sharman Consulting Ltd | Administrative & support | 2019 |
| Anna's Gardens Ltd | Administrative & support | 2009 |
| Annie Lennox Foundation | Health & social care | 2006 |
| Annie LIN Ltd | Wholesale & retail | 2023 |
| Ansell Glove Company Limited | Professional & scientific | 1978 |
| Anser Construction Limited | Construction | 2015 |
| ANT Creative London Ltd | Information & communication | 2021 |
| ANT Foundry Ltd | Manufacturing | 2021 |
| Antedote Limited | Professional & scientific | 2014 |
| Antex Interiors Ltd | Professional & scientific | 2024 |
| Anthony Chandler Associates Ltd | Professional & scientific | 2012 |
| Antodo Ltd | Construction | 2019 |
| Antunes Accountancy Services Ltd | Professional & scientific | 2018 |
| Antur 21 Ltd | Real estate | 2021 |
| ANY Moon Ltd | Information & communication | 2023 |
| Ao-You Film & Television Culture Communication Ltd | Information & communication | 2016 |
| AOE Holdings Limited | Real estate | 2024 |
| Aoifes Gelato Limited | Manufacturing | 2024 |
| APC Coach Limited | Education | 2005 |
| APC Jobs Limited | Extraterritorial | 2006 |
| Apex Brands HQ Ltd | Information & communication | 2026 |
| Apex Kitchens and Bathrooms Ltd | Construction | 2025 |
| Apex Machinery Rentals Ltd | Administrative & support | 2025 |
| API Capital Limited | Wholesale & retail | 2025 |
| API Integration Ltd | Information & communication | 2023 |
| Apib Investments Limited | Professional & scientific | 2022 |
| Apkp Holdings Limited | Real estate | 2024 |
| Aplusc Property Ltd | Real estate | 2026 |
| APO & Partners Limited | Professional & scientific | 2025 |
| Apollo Black Limited | Information & communication | 2019 |
| Apple Tree Fairy Ltd | Other services | 2025 |
| Appleby Cafe Ltd | Hospitality | 2019 |
| Applied Music Limited | Administrative & support | 1987 |
| Approved Roofing & Property Maintenance Limited | Other services | 2011 |
| Apricot IT Limited | Information & communication | 2015 |
| Après Ltd | Wholesale & retail | 2026 |
| Apsley Hall Limited | Real estate | 2002 |
| Aqoustics Ltd | Information & communication | 2023 |
| Aqua Azzurra Ltd. | Construction | 2003 |
| Aquarius Properties Limited | Real estate | 2007 |
| AR Property Investments & Management Ltd | Real estate | 2019 |
| Arabian Library Limited | Information & communication | 2002 |
| Arabian Publishing Ltd | Information & communication | 2002 |
| Aragon Court Residents Association Limited | Real estate | 1959 |
| Arakawa Ride Limited | Wholesale & retail | 2023 |
| Arambam Ltd | Real estate | 2024 |
| Arash JAM Studio Ltd | Professional & scientific | 2019 |
| ARB Assure Consulting Ltd | Professional & scientific | 2024 |
| Arben Building Contractors Limited | Construction | 2005 |
| Arbitrage Advisory Ltd | Professional & scientific | 2017 |
| Arblaster Associates Ltd | Professional & scientific | 2017 |
| Arbright Dispute Resolution Advisory Limited | Professional & scientific | 2023 |
| ARC Software Consultancy Limited | Information & communication | 1990 |
| Arcc International Ltd | Wholesale & retail | 2018 |
| Architecs Limited | Professional & scientific | 2007 |
| Archive Services Limited | Information & communication | 2017 |
| Arct Limited | Real estate | 2022 |
| Arden Solutions & Consultancy Services Ltd | Information & communication | 2019 |
| Arendair Ltd | Financial services | 2017 |
| Arendeh Homes Ltd | Real estate | 2023 |
| Ares IT Enterprise Ltd | Information & communication | 2026 |
| Argenix Ltd | Financial services | 2025 |
| Argentum Engineering Limited | Professional & scientific | 2024 |
| Argyle Mansions (Surbiton) Limited | Households | 2008 |
| Arielle Travels Ltd | Hospitality | 2023 |
| Arise Limited | Professional & scientific | 2023 |
| Arkaa Ltd | Other services | 2023 |
| Arlington Communications Ltd | Professional & scientific | 2026 |
| ARM Properties London Ltd | Professional & scientific | 2019 |
| Arneva Limited | Professional & scientific | 2023 |
| Aroma-Medics Limited | Professional & scientific | 2004 |
| ARQ Estates PVT Ltd | Real estate | 2021 |
| ARQ IT Consultancy PVT Ltd | Information & communication | 2016 |
| Arsmeets Ltd | Wholesale & retail | 2025 |
| Artaro Limited | Real estate | 1995 |
| Artem Building Ltd | Construction | 2013 |
| Arteventures Ltd | Wholesale & retail | 2025 |
| Artfulbites Ltd | Information & communication | 2023 |
| Articula Ltd | Wholesale & retail | 2022 |
| Artpaper INK Limited | Manufacturing | 2013 |
| Artstraws MFG Ltd | Manufacturing | 2023 |
| Artwise Limited | Professional & scientific | 2012 |
| Arunco Ltd | Information & communication | 2025 |
| AS Accounting & Taxation (UK) Ltd | Professional & scientific | 2022 |
| Asare International Legal Services Ltd | Professional & scientific | 2024 |
| Ascension Road Ltd | Other services | 2024 |
| Ascent Management Company (Weybridge) Limited | Households | 2002 |
| Asgard Ventures Limited | Hospitality | 2015 |
| ASH Pictures Ltd | Information & communication | 2024 |
| ASH View Surbiton RTM Company Limited | Households | 2025 |
| Ashcroft Road Limited | Real estate | 2025 |
| Ashford Hotel Operations Limited | Hospitality | 2025 |
| Ashford Hotel Property Limited | Real estate | 2025 |
| Ashleigh Louise Consulting Limited | Professional & scientific | 2022 |
| Ashurst Plumbing and Heating Limited | Construction | 2015 |
| Ashworth Plumbing & Heating Ltd | Construction | 2023 |
| Asian Development and Investment Corporation Limited | Real estate | 2016 |
| ASK Accounting Limited | Professional & scientific | 2008 |
| ASK Superstore Ltd | Wholesale & retail | 2018 |