| Aquila Analytics Ltd | Information & communication | 2023 |
| Ardan&Mk Ltd | Transport & logistics | 2021 |
| Ardex Holdings UK Limited | Manufacturing | 2001 |
| Ardex Investments UK Limited | Professional & scientific | 2002 |
| Arenval Ltd | Manufacturing | 2020 |
| Argent Country Homes Limited | Construction | 1986 |
| ARH Athletics Equipment Ltd | Extraterritorial | 2015 |
| ARH Sports Equipment Ltd | Manufacturing | 2016 |
| Arion Estates Limited | Extraterritorial | 1993 |
| ARK Pharma Services Ltd | Professional & scientific | 2022 |
| ARR Motor Group Limited | Wholesale & retail | 2024 |
| Arron Potter Heating & Plumbing Ltd | Construction | 2023 |
| Art Market Intelligence Ltd | Information & communication | 2021 |
| Artene Care Ltd | Transport & logistics | 2018 |
| Arthur Heath & Co.,Limited | Wholesale & retail | 1922 |
| Artisan Technology Limited | Information & communication | 2006 |
| Artisteel Limited | Manufacturing | 2014 |
| Arusi Limited | Transport & logistics | 2023 |
| Aryan Healthcare Solutions Ltd | Health & social care | 2020 |
| Ashborn Ltd | Wholesale & retail | 2024 |
| Ashworth Solutions Ltd | Information & communication | 2004 |
| ASP Environmental Limited | Water & waste | 2018 |
| Aspect Landscaping Limited | Administrative & support | 2014 |
| Associated Casing Co. Limited | Manufacturing | 1971 |
| Associated Protein Limited | Extraterritorial | 2024 |
| Assured Packaging Products Ltd | Wholesale & retail | 2020 |
| Astreon Life Sciences Limited | Professional & scientific | 2026 |
| Atkins Vehicle Services Ltd | Wholesale & retail | 2024 |
| ATM Fabrications Ltd | Manufacturing | 2023 |
| ATM Steel Group Ltd | Financial services | 2018 |
| ATM Steel Limited | Construction | 2018 |
| ATM UK Construction Ltd | Construction | 2011 |
| ATM UK Properties Ltd | Construction | 2020 |
| ATM UK Services Limited | Administrative & support | 2018 |
| Atterton and Ellis Limited | Manufacturing | 1941 |
| Automotive Sporting Heritage Limited | Manufacturing | 2022 |
| Autonomow Ltd | Extraterritorial | 2022 |
| Avtar Capital Limited | Information & communication | 2023 |
| Awebox Ltd | Wholesale & retail | 2017 |
| Axcelot Ltd | Information & communication | 2018 |
| Axis Site & Logistics Ltd | Transport & logistics | 2026 |
| AZ Solutionz Limited | Professional & scientific | 2014 |
| Azasons Group Ltd | Financial services | 2026 |
| Azasons Property Ltd | Real estate | 2026 |
| B & C Glass Limited | Construction | 1981 |
| B & J Motors Limited | Wholesale & retail | 2003 |
| B D S (Suffolk) Limited | Wholesale & retail | 1991 |
| B K Sargeant & SON Limited | Construction | 2017 |
| B.Chandler & Sons Engineering Maintenance Limited | Administrative & support | 2023 |
| B.S. Fellows Holdings Limited | Financial services | 2024 |
| B.S. Fellows Limited | Real estate | 1964 |
| Babyli Ltd | Wholesale & retail | 2024 |
| BAC Attachments Limited | Extraterritorial | 2017 |
| Badger HUT Ltd | Professional & scientific | 2022 |
| Bailey Digital Classroom Limited | Extraterritorial | 2022 |
| Barnley Dog Park Ltd | Other services | 2023 |
| Barrel Broking Limited | Professional & scientific | 2017 |
| Barsey Close Residents Association Limited | Professional & scientific | 1995 |
| Bayley Holdings Ltd | Financial services | 2020 |
| BB MX Sales and Servicing Ltd | Wholesale & retail | 2025 |
| BDI Developments Limited | Real estate | 2019 |
| BE Inspired Training Ltd | Education | 2012 |
| Beaphar UK Limited | Wholesale & retail | 1994 |
| Beauty Training Intl Limited | Other services | 2012 |
| Beesaway Ltd | Professional & scientific | 2023 |
| Bella HR Solutions Ltd | Construction | 2020 |
| Bellcourt Limited | Information & communication | 1992 |
| Benfa Limited | Health & social care | 2013 |
| Bennett Locksmiths Ltd | Administrative & support | 2026 |
| Benwell Interiors Ltd | Construction | 2017 |
| Bernhard & Co. Limited | Manufacturing | 1984 |
| Best of Lime Ltd | Manufacturing | 2014 |
| Best Quality Supermarket Limited | Wholesale & retail | 2025 |
| Bianca-N Ltd | Wholesale & retail | 2023 |
| Bicycle Association of Great Britain Limited(The) | Other services | 1973 |
| Bienestar 360 Ltd | Health & social care | 2018 |
| Big Green BUS Company Limited | Transport & logistics | 2012 |
| Big Smoke Productions Limited | Arts & recreation | 2020 |
| Billcentric Ltd | Information & communication | 2024 |
| Billson Limited | Wholesale & retail | 2003 |
| Biocera Medical Limited | Professional & scientific | 2020 |
| Bits Phile Limited | Administrative & support | 2024 |
| Bizscale UK Ltd | Professional & scientific | 2024 |
| BJM (Waste) Limited | Administrative & support | 2011 |
| Black Velvet London Beauty Ltd | Other services | 2017 |
| Blackoak Services Ltd | Administrative & support | 2025 |
| Bloomhaven Education Ltd. | Education | 2017 |
| BML Installations Limited | Administrative & support | 2015 |
| BNS Consults Ltd | Information & communication | 2018 |
| Bracken Art Handling Limited | Transport & logistics | 2025 |
| Brandon Consulting Services Limited | Professional & scientific | 2016 |
| Brenda Phillips Ltd | Extraterritorial | 2024 |
| Brenston Property Ltd | Real estate | 2017 |
| Brew and Toast Limited | Wholesale & retail | 2025 |
| Brightwall FM Limited | Administrative & support | 2023 |
| Brits Properties Limited | Real estate | 2024 |
| Broad Property Developements Ltd | Construction | 2025 |
| Browne Surveying Ltd | Professional & scientific | 2024 |
| Brybank Road (Haverhill) Management Company Limited | Households | 2017 |
| Bryson Business Support Limited | Administrative & support | 2020 |