| AT Design Building Contractors LLP | | 2019 |
| AT Drive LP | | 2014 |
| AT Edinburgh Ltd | Hospitality | 2026 |
| AT Edinburgh Property Ltd | Real estate | 2026 |
| AT Freight LP | | 2016 |
| AT Golden LP | | 2016 |
| AT Home in Edinburgh Ltd. | Real estate | 2010 |
| AT SC Ltd | Hospitality | 2016 |
| AT the Market Limited | Administrative & support | 2015 |
| AT the Studio Ltd | Other services | 2021 |
| At-Abray LP | | 2016 |
| At-Tawheed (Scotland) Limited | Education | 2014 |
| ATA Trading Limited | Wholesale & retail | 2014 |
| Atai Mill LP | | 2013 |
| Ataka LP | | 2015 |
| Atalaya Alliance LLP | | 2013 |
| Ataraxis Entertainment Ltd | Information & communication | 2022 |
| Ataraxy International LP | | 2022 |
| Atargis Energy UK Limited | Financial services | 2025 |
| ATB Consultancy Limited | Professional & scientific | 2025 |
| ATB International Supplies | | 1994 |
| ATB Kelpie Wind Limited | Energy | 2016 |
| ATC Advanced Technolgy Consultants & Co | | 1992 |
| ATC Land and Property Limited | Real estate | 2026 |
| ATC Property Investment Ltd | Real estate | 2020 |
| Ateal Planning & Environment Ltd | Professional & scientific | 2015 |
| Atega International LP | | 2015 |
| Atelier E.B Limited | Arts & recreation | 2014 |
| Atelier Mistral Limited | Wholesale & retail | 2019 |
| Atelier Printworks Limited | Manufacturing | 2025 |
| Ately LP | | 2013 |
| Aten Therapeutics Ltd | Professional & scientific | 2016 |
| Atep 2007 (CIV) Limited Partnership | | 2010 |
| Atep 2007 Limited Partnership | | 2010 |
| Atep 2008 Co-Invest Limited Partnership | | 2009 |
| Atep 2008 Direct Holdings Limited Partnership | | 2009 |
| Atep 2009 Co-Invest Limited Partnership | | 2009 |
| Atep 2009 Direct Holdings Limited Partnership | | 2009 |
| Atep 2010 (CIV) Limited Partnership | | 2010 |
| Atep 2010 Co-Invest Limited Partnership | | 2010 |
| Atep 2010 Direct Holdings Limited Partnership | | 2010 |
| Atep 2010 Funds Limited Partnership | | 2010 |
| Athair Ventures Ltd | Professional & scientific | 2026 |
| Athanor Media Labs Ltd | Information & communication | 2025 |
| Atharra Limited | Professional & scientific | 2024 |
| Atharva Infotech Limited | Information & communication | 2011 |
| Atharva Lettings Ltd | Real estate | 2022 |
| Athen Energy Ltd | Professional & scientific | 2023 |
| Athena BIO Ltd | Professional & scientific | 2026 |
| Athena Coaching and Consulting Ltd | Professional & scientific | 2022 |
| Athena Language Camps Ltd | Education | 2025 |
| Athena Optics LP | | 2011 |
| Athena Personal Training Ltd | Arts & recreation | 2017 |
| Athena Planning & Development Limited | Construction | 2018 |
| Athena Restaurant Ltd | Hospitality | 2025 |
| Athena's Trades Limited | Information & communication | 2025 |
| Athinaida Ltd | Wholesale & retail | 2019 |
| Athles Coaching LP | | 2025 |
| Athlete Always Limited | Education | 2024 |
| Athletic Arms Ltd | Hospitality | 2015 |
| Athletic Evolution Consulting Ltd | Arts & recreation | 2023 |
| Athletic Evolution Ltd | Education | 2021 |
| Athletic Origin Ltd | Wholesale & retail | 2020 |
| Athlos Fitness Ltd | Other services | 2025 |
| Atholl Forecourt Limited | Wholesale & retail | 2025 |
| Atholl Holdings Ltd | Wholesale & retail | 2023 |
| Atholl Incorporations Limited | Professional & scientific | 2000 |
| Atholl Property Management Limited | Real estate | 2015 |
| Atholl Security Trustee Limited | Professional & scientific | 2016 |
| ATHOLLCO10 Limited | Manufacturing | 2024 |
| Atholldawn Limited | Other services | 2000 |
| Athraa Designs Limited | Wholesale & retail | 2021 |
| Athron Hill Contracts Limited | Construction | 2021 |
| Athron Hill DEV Co Limited | Construction | 2015 |
| Athron Hill DEV Co Phase 3 Ltd | Construction | 2023 |
| Atif Nosher Ltd | Wholesale & retail | 2025 |
| Atina Developments Ltd | Construction | 2012 |
| Atinnovation Analysis Ltd | Information & communication | 2023 |
| Ativa Property Ltd | Real estate | 2014 |
| ATK Rentals Ltd | Administrative & support | 2026 |
| Atka Intersoft Associates | | 1993 |
| Atkairos Limited | Information & communication | 2020 |
| Atkin Marine Limited | Health & social care | 2020 |
| Atlant Advisors LP | | 2015 |
| Atlant Capital LP | | 2015 |
| Atlant Leader LP | | 2015 |
| Atlant Sales LP | | 2016 |
| Atlanta Corporation L.P. | | 2009 |
| Atlanta Productions LP | | 2016 |
| Atlantas International Ltd | Wholesale & retail | 2024 |
| Atlantic AI Ltd | Information & communication | 2024 |
| Atlantic Assets Trust Limited | Financial services | 2008 |
| Atlantic Carry Investment LP | | 2018 |
| Atlantic Club LP | | 2017 |
| Atlantic Commerce LP | | 2017 |
| Atlantic Europe Investments LP | | 2010 |
| Atlantic Gate Ideas LP | | 2026 |
| Atlantic GP LLP | | 2018 |
| Atlantic Intertrade L.P. | | 2011 |
| Atlantic Mariculture Ltd | Agriculture & fishing | 2018 |