| Amber Construction Services Limited | Construction | 2001 |
| Amber Property Portfolio Limited | Real estate | 2018 |
| Ambitious Children's Homes Essex Ltd | Health & social care | 2024 |
| Ambitious Children's Homes Ltd | Health & social care | 2022 |
| Ambitious Healthcare Group Ltd | Administrative & support | 2015 |
| Ambitious Healthcare Ltd | Administrative & support | 2021 |
| Ambo Services PVT Ltd | Wholesale & retail | 2025 |
| AMC Dryliners Ltd | Construction | 2025 |
| AMC Solutions Ltd | Wholesale & retail | 2025 |
| Ameen CAB Services Limited | Transport & logistics | 2022 |
| Ameerah Childcare Limited | Health & social care | 2023 |
| Ameps Consultancy Ltd | Professional & scientific | 2022 |
| Amethyst Ventures Ltd | Information & communication | 2019 |
| Amez Property Group Ltd | Real estate | 2026 |
| AMG City Tiling Ltd | Construction | 2024 |
| AMG London Masonry & Facades Ltd | Construction | 2025 |
| AMG Motors Ltd | Wholesale & retail | 2018 |
| Amiiza Ltd | Real estate | 2024 |
| Amimady Construction Company Limited | Construction | 2016 |
| Aminvest Group Ltd | Real estate | 2023 |
| Amir Shaikh Limited | Other services | 2016 |
| Amirah Bakers Limited | Manufacturing | 2016 |
| Amirah Wholesale Ltd | Wholesale & retail | 2026 |
| AMJ Contruction Limited | Construction | 2026 |
| Amjs Services Limited | Hospitality | 2021 |
| AMK Nexus Ltd | Wholesale & retail | 2025 |
| AMK OFF Licence Ltd | Wholesale & retail | 2024 |
| AMK Properties London Ltd | Real estate | 2025 |
| Amkb Investments Ltd | Real estate | 2024 |
| Amla Cafe Ltd | Hospitality | 2024 |
| AMM Advisors Ltd | Administrative & support | 2025 |
| Amobix Digital Networks Limited | Information & communication | 2017 |
| AMP Generation Ltd | Professional & scientific | 2025 |
| Ampere Power Engineering Ltd | Construction | 2025 |
| Amplery Properties Ltd | Real estate | 2021 |
| Amponlynx Ltd. | Construction | 2016 |
| Amrahprx Ltd | Wholesale & retail | 2023 |
| Amram Ltd | Manufacturing | 2016 |
| Amrik Contractors Limited | Construction | 2025 |
| Amringroup Limited | Construction | 2024 |
| AMS Housing Ltd | Real estate | 2009 |
| AMS Maintenance Limited | Construction | 2019 |
| Amsq Ltd | Wholesale & retail | 2025 |
| Amze Management Limited | Real estate | 2026 |
| ANA Merrior Limited | Professional & scientific | 2024 |
| ANA Textile Limited | Wholesale & retail | 2021 |
| Analytics Team Ltd | Information & communication | 2026 |
| Anambra Wolf Ltd | Water & waste | 2024 |
| Anayah Renovation Titan Limited | Construction | 2023 |
| Andee Social Consult Ltd | Health & social care | 2026 |
| Andfriends Productions CIC | Arts & recreation | 2024 |
| Andhra Spice Private Limited | Hospitality | 2022 |
| Andrada Construct Ltd | Construction | 2023 |
| Andraste Group Ltd | Manufacturing | 2021 |
| Andre Labi Professional Services Ltd | Information & communication | 2019 |
| Andrei Fixing Ltd | Construction | 2026 |
| Andreinechita Ltd | Construction | 2018 |
| Andres Solusan Ltd | Construction | 2025 |
| Andrew & Edyta Catering Ltd | Hospitality | 2019 |
| Andrew Ventures Ltd | Transport & logistics | 2025 |
| Andysarfo Construction and HC Limited | Construction | 2022 |
| Anetsh Care Ltd | Health & social care | 2021 |
| Ange Wise Limited | Wholesale & retail | 2018 |
| Angel Care and Recruitment Ltd | Administrative & support | 2022 |
| Angel Crowns Empowerment CIC | Other services | 2024 |
| Angeliq Ltd | Administrative & support | 2019 |
| Angels Care Solutions Limited | Health & social care | 2016 |
| Angels Resources & Supplies Ltd | Construction | 2020 |
| Angels Touch Recruitment Limited | Administrative & support | 2017 |
| Angelz Trust Ltd | Health & social care | 2023 |
| Anglebury Limited | Information & communication | 1998 |
| Anike London Limited | Professional & scientific | 2025 |
| Anikky Childcare Limited | Education | 2024 |
| Aninng Group Ltd | Other services | 2026 |
| Anirotrans Ltd | Transport & logistics | 2017 |
| Anji & ANI Lake Solicitors Ltd | Professional & scientific | 2025 |
| Anka Consultancy Ltd | Information & communication | 2023 |
| Ankh Security Limited | Administrative & support | 2007 |
| Anmol Grill and Restaurant Limited | Hospitality | 2026 |
| Annasalad Ltd | Hospitality | 2020 |
| Annietho Limited | Hospitality | 2011 |
| Anopex Ltd | Information & communication | 2009 |
| Anpc Healthcare & Travel Clinic Ltd | Health & social care | 2011 |
| ANS22TRANS Limited | Transport & logistics | 2023 |
| Ansari Construction Limited | Construction | 2025 |
| Anteiku Coffee Shop Limited | Hospitality | 2021 |
| Anthonyraj Ltd | Health & social care | 2025 |
| Anthropocene Ltd | Professional & scientific | 2017 |
| Antim West UK Limited | Wholesale & retail | 2011 |
| Antonia Dimante Ltd | Wholesale & retail | 2026 |
| ANU Food Service Limited | Hospitality | 2023 |
| Anumta Ltd | Administrative & support | 2024 |
| Anyisys Limited | Construction | 2014 |
| AO Oliver Ltd | Construction | 2025 |
| AO Works Ltd | Professional & scientific | 2022 |
| AP Bull Properties Ltd | Real estate | 2025 |
| Apache Tyres (Swansea) Ltd | Wholesale & retail | 2025 |
| Apeka Limited | Construction | 2009 |
| Apex Auto Parts Ltd | Wholesale & retail | 2018 |
| Apex Autos & Motoring Ltd | Wholesale & retail | 2026 |