| Amikashopper Ltd | Wholesale & retail | 2024 |
| Amista Holdco Limited | Real estate | 2026 |
| Amjoh Ltd | Health & social care | 2024 |
| Amory London Ltd | Wholesale & retail | 2021 |
| Amory LUX Ltd | Wholesale & retail | 2025 |
| Amos Goldreich Architecture Limited | Professional & scientific | 2010 |
| Amram Capital Limited | Professional & scientific | 2015 |
| Amsco Properties UK Limited | Real estate | 2015 |
| Amsky Labs Ltd | Wholesale & retail | 2025 |
| AMT Surveying Ltd | Construction | 2025 |
| Amtra LDN Ltd | Wholesale & retail | 2020 |
| Amuse Bouche Catering Ltd | Hospitality | 2023 |
| AMY Stoddart Studio Limited | Professional & scientific | 2020 |
| Amynta Partners Ltd | Administrative & support | 2015 |
| Amyrah Aaryan Ltd | Real estate | 2018 |
| AMZ Trading Ltd | Administrative & support | 2017 |
| Amza DC Ltd | Construction | 2019 |
| Anadarajah Trading Limited | Administrative & support | 2020 |
| Anaid Estates Limited | Real estate | 1979 |
| Anantaa Properties Ltd | Real estate | 2024 |
| Anavis Computing Services Ltd | Information & communication | 2022 |
| Anavive Limited | Wholesale & retail | 2025 |
| ANB Barber Limited | Other services | 2023 |
| AND CUT Media LLP | | 2026 |
| AND1 Tech Ltd | Other services | 2024 |
| Andalo Ltd | Professional & scientific | 2014 |
| Andavis Limited | | 2012 |
| Andean Emerald Limited | Real estate | 2025 |
| Anderson Parker Ltd | Real estate | 2020 |
| Andola Properties Limited | Real estate | 2001 |
| Andratx Limited | Financial services | 2016 |
| Andreea Coaching Ltd | Health & social care | 2022 |
| Andrei & Dave Limited | Hospitality | 2017 |
| Andrei Logistics Transport Ltd | Transport & logistics | 2014 |
| Andrew Capital Ltd | Wholesale & retail | 2025 |
| Andrew Homes Ltd | Construction | 2020 |
| Andrew Isaacs Machinery International Ltd. | Wholesale & retail | 1999 |
| Andrinelu Ltd | Transport & logistics | 2017 |
| Andrius Tolis N. COM Limited | Manufacturing | 2005 |
| Andy Formwork Ltd | Construction | 2023 |
| ANG Cumbria Limited | Construction | 2016 |
| Angel Lane Investments Ltd | Real estate | 2026 |
| Angel Lettings Ltd | Real estate | 2000 |
| Angel Property Investments Limited | Real estate | 2002 |
| Angela Murray Limited | Information & communication | 2008 |
| Angelov Ltd | Construction | 2025 |
| Angitu Limited | Administrative & support | 2012 |
| Angle 138 Ltd | Professional & scientific | 2024 |
| Anglo Australian Securities Limited | Administrative & support | 2017 |
| Anglo Deer Management and Training Limited | Agriculture & fishing | 2015 |
| Anglo Deer Management Limited | Agriculture & fishing | 2015 |
| Anglo Saxon Scaffolding Ltd | Construction | 2015 |
| Anglo Swiss Façade Design Limited | Professional & scientific | 2020 |
| Animals at Home (South East Herts) Limited | Professional & scientific | 2018 |
| Anisan Fashion UK Limited | Manufacturing | 2016 |
| Aniva Property Ltd | Real estate | 2022 |
| ANK Medics Ltd | Professional & scientific | 2021 |
| ANM Properties Limited | Real estate | 2009 |
| Anmac Ltd | Manufacturing | 2006 |
| Anmsp Limited | Financial services | 2016 |
| Anna Trevelyan Limited | Arts & recreation | 2013 |
| Annandale House Freehold Limited | Real estate | 2014 |
| Annointed Hands Ltd | Hospitality | 2019 |
| Annulet Limited | Information & communication | 2000 |
| Another Acronym Ltd | Other services | 2013 |
| Another Bloomin' Christmas Limited | Information & communication | 2018 |
| Another Boba Shop Limited | Hospitality | 2022 |
| Anraw Medical Limited | Health & social care | 2016 |
| Ansh Financial Services Ltd | Financial services | 2024 |
| Antagonist Films Limited | Information & communication | 2024 |
| Antalmi Ltd | Administrative & support | 2018 |
| Anthology Holdings Limited | Real estate | 2020 |
| Anthony Bush Services Ltd | Wholesale & retail | 2018 |
| Anthony Lancaster Carpentry Ltd | Construction | 2019 |
| Anthony Spencer Projects Ltd | Construction | 2022 |
| Antimony Ltd | Professional & scientific | 2018 |
| Antoine Multimedia Limited | Arts & recreation | 2014 |
| Anton & G Builds Ltd | Construction | 2018 |
| Antoni Limited | Transport & logistics | 2014 |
| Antrotech Limited | Manufacturing | 2014 |
| ANV Barber Ltd | Other services | 2026 |
| Anytime Haulage Ltd | Transport & logistics | 2014 |
| Anza Estates Limited | Real estate | 2022 |
| AOP Art of Presentation Limited | Manufacturing | 2011 |
| Aparthotel Dundee LLP | | 2017 |
| Aparthotel Services (Dundee) Ltd | Hospitality | 2017 |
| APARTMENTS4U Limited | Real estate | 2004 |
| Apex Agencies and Distribution Limited | Wholesale & retail | 1995 |
| Apex Creative Agency Ltd | Information & communication | 2019 |
| Apex Fire Safety Limited | Public administration | 2025 |
| Apex Fitness Club Limited | Health & social care | 2023 |
| Apex Property Co. Ltd | Real estate | 1982 |
| Apex Property Investments Limited | Construction | 1992 |
| Apexchase Property Management Limited | Extraterritorial | 2005 |
| Apic Tech Ltd | Information & communication | 2022 |
| APL Advisory Ltd | Professional & scientific | 2026 |
| APN AUR Ltd | Wholesale & retail | 2025 |
| Apollo Dent Limited | Health & social care | 2022 |
| Aposto Ltd | Information & communication | 2020 |
| App Contracts Limited | Construction | 2012 |