| Assurecert Limited | Professional & scientific | 2025 |
| Astaldo Trade LP | | 2015 |
| Astellis Limited | Education | 2017 |
| Astrojet Communications L.P. | | 2017 |
| Astrowest L.P. | | 2015 |
| Astute Planning Limited | Financial services | 2012 |
| Astute Safety Limited | Professional & scientific | 2012 |
| Asura Financial Technologies Limited | Information & communication | 2016 |
| ASV Services Ltd | Professional & scientific | 2017 |
| ASW Consulting Limited | Professional & scientific | 2023 |
| AT Consultancy (Fife) Ltd | Professional & scientific | 2026 |
| AT Landscaping and Contracts Ltd | Administrative & support | 2024 |
| AT Offshore Solutions Ltd | Extraterritorial | 2024 |
| AT Project Delivery Services Ltd | Professional & scientific | 2019 |
| AT Your Service Scotland Limited | Administrative & support | 2017 |
| AT2006 Limited | Professional & scientific | 2006 |
| ATDD1 Ltd | Hospitality | 2016 |
| Atep 2008 (CIV) Limited Partnership | | 2009 |
| Atep 2008 Funds Limited Partnership | | 2009 |
| Atep 2009 (CIV) Limited Partnership | | 2009 |
| Atep 2009 Funds Limited Partnership | | 2009 |
| Ather & Co Ltd | Administrative & support | 2010 |
| Athlete Recovery Zone Ltd | Other services | 2024 |
| Athlone Holding Company Ltd. | Financial services | 2016 |
| Atholl Travel Ltd | Administrative & support | 2025 |
| Atikati Properties (Scotland) Ltd | Real estate | 2025 |
| Atlantic Glencairn Ltd | Real estate | 2022 |
| Atlantis LP | | 2017 |
| Atlantis North Limited | Administrative & support | 2005 |
| Atlantis Publishing Limited | Information & communication | 2017 |
| Atlantis Well Engineering Limited | Mining & quarrying | 2025 |
| Atlas Briefly Ltd | Wholesale & retail | 2025 |
| Atlas Energy Service Solutions Ltd | Professional & scientific | 2024 |
| Atlas Property Care Limited | Construction | 2006 |
| Atlas Rope and Rescue Ltd | Construction | 2026 |
| Atlas Stack Ltd | Information & communication | 2025 |
| Atma AI Limited | Information & communication | 2024 |
| Atmaal Ltd | Professional & scientific | 2020 |
| Atomic Locksmiths Ltd | Other services | 2025 |
| Atomic Number Three Ltd | Information & communication | 2025 |
| Atradeya Ltd | Information & communication | 2013 |
| Atro Holdings Ltd | Wholesale & retail | 2025 |
| Attuned Law Ltd | Professional & scientific | 2026 |
| AU Lets Ltd | Real estate | 2021 |
| Auchterhouse Country Guns Ltd | Wholesale & retail | 2024 |
| Audio Outsource Ltd | Manufacturing | 2019 |
| Auld Alliance Games Ltd | Information & communication | 2022 |
| Aura Facial Aesthetics Limited | Other services | 2017 |
| Aureisha Beauty Ltd | Wholesale & retail | 2026 |
| Aurelian Homes Limited | Construction | 2026 |
| Aurelius Property Management Ltd | Real estate | 2026 |
| Aurona Limited | Wholesale & retail | 2025 |
| Aurora 22 Ltd | Energy | 2026 |
| Aurora Edge Coaching Ltd | Professional & scientific | 2025 |
| Aurora Knight Ltd | Hospitality | 2017 |
| Auryn Consulting Limited | Hospitality | 2025 |
| Auryn Hotels Limited | Hospitality | 2025 |
| Austin James Capital Ltd | Financial services | 2026 |
| Author Interiors Limited | Other services | 2015 |
| Auto Consult ME Ltd | Administrative & support | 2024 |
| Auto Transport and Trade Limited | Wholesale & retail | 2021 |
| Autolec Solutions Ltd | Wholesale & retail | 2017 |
| Autopaint Tayside Ltd | Wholesale & retail | 2025 |
| Avadan Limited | Professional & scientific | 2017 |
| AVD Computing Ltd. | Information & communication | 2000 |
| AVE Electronics & TV Parts Limited | Wholesale & retail | 2019 |
| Avertical World Limited | Arts & recreation | 2024 |
| Aviehill Ltd | Manufacturing | 2022 |
| AVP Holdings Ltd | Real estate | 2023 |
| Avrs Trading Limited | Hospitality | 2013 |
| AW Global Ltd | Wholesale & retail | 2025 |
| AWA Building Surveyors Ltd | Professional & scientific | 2020 |
| Awan Scotland Ltd | Transport & logistics | 2019 |
| AWC1 Limited | Real estate | 1995 |
| AWD Reinforcement Limited | Construction | 2023 |
| Awfl Ltd | Professional & scientific | 2022 |
| AWH Accountants Ltd | Professional & scientific | 2005 |
| AXE Contractors Limited | Construction | 2023 |
| Axed & Enraged Limited | Arts & recreation | 2023 |
| Axil Estates Limited | Construction | 2015 |
| Axis Property GRP Ltd | Real estate | 2025 |
| Axis-Shield Limited | Financial services | 1993 |
| AXL Holdco Limited | Financial services | 2025 |
| AXL UK Limited | Transport & logistics | 2006 |
| Axsys Technology Limited | Information & communication | 1997 |
| Ayacquisitions Ltd | Information & communication | 2024 |
| Ayak London Limited | Wholesale & retail | 2025 |
| Ayatco Limited | Wholesale & retail | 2018 |
| Aydya Group Limited | Professional & scientific | 2006 |
| Aydya Holdings Limited | Financial services | 2025 |
| Aydya Limited | Wholesale & retail | 2009 |
| AYE Love Real Food Ltd | Hospitality | 2016 |
| AYE Taxi Ltd | Transport & logistics | 2022 |
| Aymaar Ltd | Real estate | 2023 |
| Ayrshire Alignment Limited | Wholesale & retail | 2020 |
| Ayrshire Stores Limited | Administrative & support | 2019 |
| Ayrshire Taxi Vans Ltd | Transport & logistics | 2012 |
| Aytekin Ltd | Hospitality | 2026 |
| Azaad (Dundee) Limited | Hospitality | 2017 |
| Azaan Healthcare (Dundee) Ltd | Health & social care | 2014 |