| Albemarle of London Limited | Administrative & support | 2010 |
| Albemarle Road (Beckenham) Maintenance Limited | Households | 1969 |
| Albermarle Hotels (NO.2) Limited | Hospitality | 2006 |
| Albermarle Hotels Limited | Hospitality | 1986 |
| Albert Road (London) Developments Ltd | Construction | 2016 |
| Albi Constructs Ltd | Construction | 2024 |
| Albi Contractors Ltd | Construction | 2011 |
| Alcazar Technologies Ltd | Wholesale & retail | 2014 |
| Alcuin Investments Ltd | Financial services | 2025 |
| Alcuts Ltd | Other services | 2022 |
| Alda Glazing Solutions Ltd | Construction | 2023 |
| Aldam Plumbing and Electrical Services Ltd | Construction | 2018 |
| Aldo's Sandwich and Coffee Bar Limited | Hospitality | 2013 |
| Aldrenor Media Group Limited | Administrative & support | 2021 |
| Aleksandra Filipovic Ltd | Professional & scientific | 2015 |
| Alepuz Legal Consulting Limited | Professional & scientific | 2012 |
| Alessia Limited | Professional & scientific | 2013 |
| Alex Conner Creative Limited | Professional & scientific | 2012 |
| Alexander Court Management Company (Shortlands) Limited | Households | 1986 |
| Alexander Dann Wealth Management Ltd | Financial services | 2020 |
| Alexander JS Limited | Professional & scientific | 2012 |
| Alexandria's Private Tuition Limited | Education | 2025 |
| Alexandu Trans Ltd | Transport & logistics | 2020 |
| Alfa Strategies Ltd | Financial services | 2019 |
| Alfadesing Ltd | Manufacturing | 2026 |
| Alfen Technology Ltd | Administrative & support | 2015 |
| Alfie Sinclair Transport Services Ltd | Transport & logistics | 2009 |
| Alfred Cenuka Ltd | Construction | 2026 |
| Algazin Software Limited | Information & communication | 2012 |
| Algebryte Learning Enterprise Limited | Education | 2025 |
| Alggaby Barber Shop Ltd | Other services | 2021 |
| Algus Limited | Real estate | 2020 |
| Alha Holdings Ltd | Real estate | 2020 |
| Align Engineering Ltd | Professional & scientific | 2024 |
| ALIGN3 Ltd | Information & communication | 2025 |
| Aligned Accountancy Group Ltd | Professional & scientific | 2018 |
| Aligned Consultancy Group Limited | Professional & scientific | 2019 |
| Alin Medina Ltd | Hospitality | 2023 |
| Alkemia Limited | Professional & scientific | 2006 |
| ALL Junk Solutions Limited | Water & waste | 2017 |
| ALL Saints Church Hall Management Company Limited | Real estate | 2000 |
| ALL Seasons PIR Ltd | Financial services | 2018 |
| ALL Smiles Dental Practice Limited | Health & social care | 2012 |
| ALL the Best Property Management Services Ltd | Households | 2026 |
| ALL UK Electric Limited | Construction | 2024 |
| ALL Year Investments Limited | Real estate | 2001 |
| Allbrown Universal Components Limited | Construction | 1975 |
| Allied Marketing Solutions Ltd | Wholesale & retail | 2013 |
| Allodi Accordions Limited | Professional & scientific | 2004 |
| Allotropia Ltd. | Information & communication | 2013 |
| Allright General Builder Limited | Construction | 2014 |
| Allstar Brokers Ltd | Wholesale & retail | 2023 |
| Allstar Property Services Ltd | Professional & scientific | 2025 |
| Alltype Holdings Limited | Financial services | 2020 |
| Alltype Paving & Building Ltd | Administrative & support | 2013 |
| Allu Ltd | Construction | 2024 |
| Allum Productions Ltd | Professional & scientific | 2021 |
| Allwoods Place Block 3 (Hitchin) RTM Company Limited | Real estate | 2025 |
| ALM Groups Services Ltd | Construction | 2026 |
| Alnitech Limited | Professional & scientific | 1992 |
| Alonak Property Ltd | Real estate | 2026 |
| Alongside Accounting Limited | Professional & scientific | 2015 |
| Aloya Ltd | Manufacturing | 2026 |
| Alpenmile Properties Limited | Real estate | 1994 |
| Alpenmind Limited | Information & communication | 2023 |
| Alpha Lotus Limited | Information & communication | 2023 |
| Alpha Omega Exports Ltd | Wholesale & retail | 2021 |
| Alpha Resin Ltd | Construction | 2021 |
| Alpha Science International Limited | Information & communication | 2000 |
| ALPHA-1 Limited | Construction | 2007 |
| Alphabet Square Management Company Limited | Households | 1988 |
| Alpine Glacier Project Limited | Professional & scientific | 2017 |
| Altgrl Ltd | Wholesale & retail | 2025 |
| Altimin IT Services Limited | Information & communication | 2024 |
| Altimin Limited | Information & communication | 2024 |
| Alton Scaffolding Ltd | Construction | 2025 |
| Alton Stepford Limited | Information & communication | 2022 |
| Altstrange Media Ltd | Information & communication | 2025 |
| Altvelop Ltd | Professional & scientific | 2019 |
| Alumo Ltd | Wholesale & retail | 2020 |
| Alvasen Ltd | Transport & logistics | 2019 |
| Alveare Property Limited | Real estate | 2025 |
| Alvectro Ltd | Manufacturing | 2025 |
| Always Caring Bromley Ltd | Health & social care | 2009 |
| ALY Investments Limited | Real estate | 2026 |
| AM Cardiac Diagnostic Services Ltd | Health & social care | 2023 |
| AM Garding Services Ltd | Administrative & support | 2025 |
| AM Growth Investments Limited | Real estate | 2017 |
| AM Healthcare Limited | Health & social care | 2012 |
| AM Italian Ltd | Hospitality | 2013 |
| Amabokkebokke Ltd | Hospitality | 2026 |
| Amadori Limited | Information & communication | 2012 |
| Amaidan Consulting Ltd | Professional & scientific | 2022 |
| Amaize Drinks Limited | Extraterritorial | 2018 |
| Amalaser Ltd | Other services | 2022 |
| Amalia Productions Limited | Information & communication | 2015 |
| Amandlendlovu Corporations Limited | Health & social care | 2019 |
| Amarium House | Professional & scientific | 2011 |
| Amazing Care & Support Services Limited | Administrative & support | 2018 |
| Amazon House RTM Company Ltd | Real estate | 2015 |