| Artisan International Trade Ltd | Manufacturing | 2025 |
| Artistic Holdings Limited | Real estate | 2023 |
| Artistra Ltd | Information & communication | 2024 |
| Artlett Limited | Extraterritorial | 2003 |
| Artmytreasure Ltd | Wholesale & retail | 2012 |
| Arunh&Co Accountancy Ltd | Professional & scientific | 2024 |
| ARV Estate Group Limited | Real estate | 2025 |
| Aryha Ltd | Wholesale & retail | 2018 |
| Arysta Lifescience U.K. JPY Limited | Professional & scientific | 2013 |
| AS Cargo Ltd | Transport & logistics | 2025 |
| AS Global Consulting Ltd | Education | 2025 |
| AS Merchandise Ltd | Wholesale & retail | 2017 |
| AS Textiles Ltd | Wholesale & retail | 2023 |
| AS UK Consultants Limited | Information & communication | 2019 |
| AS Whole Limited | Information & communication | 2024 |
| AS Wholesalebuy Ltd | Wholesale & retail | 2019 |
| Asamanco Vehicle and Machinery Rental Ltd | Administrative & support | 2019 |
| Asby Limited | Other services | 2025 |
| Ascend MC Property Limited | Real estate | 2026 |
| Ascend One Ltd | Professional & scientific | 2026 |
| Ascended Technology Limited | Real estate | 2006 |
| Ascending Addiction Ltd | Education | 2025 |
| Ascent Global Shipping UK Ltd | Transport & logistics | 2019 |
| Ascexit Limited | Financial services | 2019 |
| Asfb Productions Limited | Information & communication | 2020 |
| ASG UK PVT Limited | Wholesale & retail | 2018 |
| ASH Dent Limited | Health & social care | 2026 |
| ASH Grand Ltd | Real estate | 2025 |
| ASH Property Company (2) Ltd | Extraterritorial | 2008 |
| ASH Property Company Ltd | Extraterritorial | 2008 |
| ASH Wash Ltd | Other services | 2026 |
| Ashbourne Studios Ltd | Information & communication | 2026 |
| Ashbroad Ltd | Real estate | 2022 |
| Ashcroft Joinery Ltd. | Construction | 2011 |
| Asher Tech Solutions Limited | Wholesale & retail | 2024 |
| Ashford Corporate Ltd | Extraterritorial | 2019 |
| Ashirri Media Strategy Limited | Manufacturing | 2025 |
| Ashirus Contractors Limited | Other services | 2023 |
| Ashley Tree Services Ltd | Agriculture & fishing | 2017 |
| Ashter Estates Ltd | Real estate | 2020 |
| Ashton Builders & Repair Services Ltd | Construction | 2024 |
| Ashton Estates Ltd | Real estate | 2021 |
| Ashton House LLP | | 2010 |
| Ashton-Under-Lyne Car Wash Ltd | Other services | 2024 |
| Ashtons Estates Ltd | Other services | 2016 |
| Ashtree Estates Ltd | Real estate | 2021 |
| Ashwell Properties Ltd | Real estate | 2019 |
| Asiagate Ltd | Wholesale & retail | 2023 |
| ASK Homelets Ltd | Real estate | 2026 |
| Ask.Com Limited | Other services | 2006 |
| ASLIVING1 MCR Ltd | Wholesale & retail | 2026 |
| ASM Maintenance Ltd | Construction | 2026 |
| Asmbll Limited | Transport & logistics | 2021 |
| Asnn UK Limited | Other services | 2026 |
| Asois Chesed Ltd | Other services | 2024 |
| Aspanall Limited | Financial services | 2023 |
| Aspen House Estate Company Limited | Other services | 2021 |
| Aspen House Estate Holdings Limited | Other services | 2020 |
| Aspire + Wealth Management Limited | Financial services | 2019 |
| Aspire for Intelligent Care and Support CIC | Health & social care | 2014 |
| Aspire Home Development and Maintenance Limited | Construction | 2022 |
| Aspire Realty Investments Ltd | Real estate | 2025 |
| ASR Associate Limited | Health & social care | 2023 |
| Assemblies of GOD Incorporated | Other services | 1993 |
| Assenda Limited | Extraterritorial | 2015 |
| Asset Recovery (North West) Ltd | Extraterritorial | 2012 |
| Assetedge Limited | Financial services | 2021 |
| Asso Technologies Ltd | Information & communication | 2026 |
| Association for Women's Awareness and Rural Development (Award), UK C.I.C. | Health & social care | 2024 |
| AST Football Management Ltd | Arts & recreation | 2020 |
| Astbury Lane Nursery Limited | Health & social care | 2016 |
| Asteer Planning LLP | | 2021 |
| Asteer Strategic Limited | Professional & scientific | 2024 |
| ASTERA1 Limited | Extraterritorial | 2025 |
| Asterisk International (UK) Limited | Real estate | 2021 |
| Aston Taylor Properties Limited | Real estate | 1996 |
| Astonquote Limited | Real estate | 1982 |
| Astronix Systems Limited | Information & communication | 2026 |
| ASV Properties Limited | Real estate | 2017 |
| ASV Travel Logistics Ltd | Transport & logistics | 2026 |
| At-Bay Group (UK) Limited | Financial services | 2025 |
| Atalp Consulting Ltd | Information & communication | 2022 |
| Atcp Ltd | Hospitality | 2022 |
| Atda Ltd | Manufacturing | 2022 |
| Atelier ACS Limited | Professional & scientific | 2021 |
| Atelier Design Studio Limited | Extraterritorial | 2014 |
| ATH Fine Fragrance Ltd | Manufacturing | 2025 |
| Athenyx Group Ltd | Information & communication | 2025 |
| ATHERTON3 Ltd | Real estate | 2013 |
| Atid Assets Ltd | Real estate | 2026 |
| Atid Investments Ltd | Real estate | 2026 |
| Atius Management Ltd | Professional & scientific | 2020 |
| Atlanta Insurance Intermediaries Limited | Financial services | 1963 |
| Atlanta Investment Holdings 3 Limited | Financial services | 2016 |
| Atlas Diagnostics Education Limited | Health & social care | 2023 |
| Atlas Diagnostics Limited | Health & social care | 2011 |
| Atlas Diagnostics Reporting Limited | Health & social care | 2023 |
| Atlas Diagnostics Solutions Limited | Health & social care | 2023 |
| Atlas Diagnostics Ultrasound Limited | Health & social care | 2023 |
| Atlas Immigration Ltd | Professional & scientific | 2025 |