| AJD Mobile Catering Ltd | Hospitality | 2026 |
| Ajhwm Properties Ltd | Wholesale & retail | 2019 |
| AJS Decorating Limited | Construction | 2011 |
| AK Guildford Limited | Real estate | 2014 |
| AK Robertsbridge Limited | Construction | 2023 |
| Akirma Luxe Ltd | Wholesale & retail | 2022 |
| Akshar Management Ltd | Real estate | 2020 |
| AL Murattabat AL Masriya Ltd | Wholesale & retail | 2026 |
| Alabaster Homes Ltd | Real estate | 2024 |
| Albacore Building Services Limited | Construction | 1976 |
| Albion Beverages Limited | Professional & scientific | 2011 |
| Alexandra Bickerdike Ltd | Administrative & support | 2023 |
| Alfie Scott Consulting Limited | Financial services | 2021 |
| Alflo Limited | Construction | 2023 |
| Alflo Retail Consulting Ltd | Professional & scientific | 2023 |
| Alfred the Great Pest Control Ltd | Administrative & support | 2026 |
| Alibrico Limited | Wholesale & retail | 2020 |
| Alic Property Investment Limited | Real estate | 2019 |
| ALL About Swimming Ltd | Arts & recreation | 2024 |
| ALL Angles Tree Care Limited | Administrative & support | 2019 |
| ALL GAS Maintenance AGM Limited | Construction | 2018 |
| ALL in Construction (London) Ltd | Construction | 2025 |
| ALL Points Management Limited | Professional & scientific | 2019 |
| ALL Screeds Ltd | Construction | 2020 |
| ALL Works Group Ltd | Construction | 2010 |
| Allen&Co Plumbing and Heating Services Ltd | Construction | 2019 |
| Allmac Haulage Limited | Transport & logistics | 2010 |
| Alltype Facilities Limited | Administrative & support | 2014 |
| Alltype Group Ltd | Administrative & support | 2006 |
| Alltype Lettings Ltd | Extraterritorial | 2017 |
| Alora Health Limited | Wholesale & retail | 2023 |
| Alos Consulting Limited | Professional & scientific | 2006 |
| Alpha Jumper Limited | Extraterritorial | 2019 |
| Alpha SAM Limited | Health & social care | 2017 |
| Alpinedawn Property Management Limited | Real estate | 2002 |
| Alps Wealth Limited | Real estate | 2024 |
| Alsaradil Limited | Real estate | 2021 |
| ALT IQ Consulting Ltd | Professional & scientific | 2025 |
| Alumrose LLP | | 2021 |
| Amadeus Primary Academies Trust | Education | 2015 |
| Amayum Group Ltd | Real estate | 2018 |
| AMB Print & Design Ltd | Manufacturing | 2022 |
| Ambassador Court (London) Limited | Real estate | 1997 |
| Ambassador Insulations (London) Limited | Construction | 2019 |
| Amber Refurbishment Services Ltd | Construction | 2013 |
| Ambleside (Freehold) Limited | Households | 2023 |
| Amda Developments Limited | Construction | 2006 |
| Amir and Chase Ltd | Real estate | 2025 |
| Ammica Holdings Limited | Real estate | 2024 |
| Ammica Solutions Limited | Construction | 2013 |
| AMP Photography Ltd | Other services | 2016 |
| Ample Buying Ltd | Wholesale & retail | 2025 |
| AMS Consulting Services Ltd | Extraterritorial | 2022 |
| Anarella Limited | Information & communication | 2010 |
| Ancura Aesthetics Ltd | Health & social care | 2026 |
| Ancura Health Ltd | Wholesale & retail | 2025 |
| Anderson Construction Solutions Limited | Construction | 2019 |
| Anderton Property Developments Ltd | Construction | 2020 |
| Andreea Vesey (Baciu) Ltd | Public administration | 2024 |
| Aneesha Nominees Limited | Administrative & support | 2002 |
| Angegra Nursery and Preschool Limited | Health & social care | 2024 |
| Angel Homes (Kent) Limited | Real estate | 2018 |
| Anita Sarkadi Enterprise Limited | Health & social care | 2024 |
| Annetech Limited | Energy | 2011 |
| Annovia Property Limited | Construction | 2025 |
| Anthony Staines Limited | Construction | 2016 |
| Apex Fire Solutions Ltd | Public administration | 2024 |
| APK London Ltd | Professional & scientific | 2023 |
| Apollo Clinics Ltd | Health & social care | 2023 |
| Apollo Osteopathy Limited | Health & social care | 2021 |
| App Management Limited | Real estate | 2018 |
| Appity Development Ltd | Information & communication | 2024 |
| Apply-It Limited | Wholesale & retail | 2020 |
| Apricus LDN Ltd | Arts & recreation | 2024 |
| Aquatic Maintenance Ltd | Agriculture & fishing | 2013 |
| Aqueous Design Ltd | Wholesale & retail | 2012 |
| AR Property Partners Limited | Real estate | 2025 |
| Arbor Projects Limited | Construction | 2015 |
| ARC Cleaning Limited | Other services | 2017 |
| Arcadian Solutions Limited | Information & communication | 2021 |
| Archery AP Ltd | Real estate | 2024 |
| Arden House Management Ltd | Real estate | 2015 |
| Arebe Marketing Limited | Professional & scientific | 2014 |
| Aris Project Ltd | Construction | 2019 |
| Arktos Limited | Real estate | 2024 |
| Armev Limited | Other services | 2018 |
| Armour Investments Ltd | Real estate | 2015 |
| Armoured Security Ltd | Administrative & support | 2024 |
| Arpentage Limited | Professional & scientific | 2014 |
| ARS Infotech Ltd | Information & communication | 2010 |
| Artemis Self Defence Ltd | Education | 2026 |
| Artemisia Magazine Ltd | Wholesale & retail | 2025 |
| Arthaco Limited | Other services | 2018 |
| Artistic Flooring Limited | Construction | 2005 |
| Arya Trading Limited | Financial services | 2022 |
| Asbol Realty Ltd | Real estate | 2025 |
| ASC Partnership Limited | Financial services | 1986 |
| Ascot Court RTM Company Limited | Households | 2022 |
| ASD Finance Ltd | Financial services | 2013 |
| Asghar Finance House Limited | Financial services | 2019 |