| ASB Bookkeeping Limited | Professional & scientific | 2016 |
| Ascending Dimensions Media Ltd | Information & communication | 2018 |
| Asgard Fitness Ltd | Arts & recreation | 2016 |
| ASH Tree Veterinary Centre Ltd | Professional & scientific | 2010 |
| Ashanim Company Limited | Health & social care | 2018 |
| Ashbourne Court Property Management Company Limited | Professional & scientific | 2003 |
| Ashbrook Direct Limited | Professional & scientific | 2008 |
| Ashfield Green Consulting Ltd | Wholesale & retail | 2023 |
| Ashley Convenience Store Ltd | Wholesale & retail | 2025 |
| Ashley House Hotel Ltd | Hospitality | 2013 |
| Ashprijo Limited | Health & social care | 2018 |
| Ashridge Bloodstock Ltd | Agriculture & fishing | 2022 |
| Ashtree Property Improvements Ltd | Construction | 2014 |
| ASK Publishing Limited | Information & communication | 2018 |
| Asmbly Live Ltd | Information & communication | 2025 |
| Associated British Caravans (Hire) Limited | Extraterritorial | 1967 |
| Associated British Caravans Limited | Extraterritorial | 1936 |
| Assured Structures Ltd | Construction | 2024 |
| Astral Energy Limited | Professional & scientific | 2026 |
| AT Brunton Homes Ltd | Real estate | 2017 |
| Ataraph Limited | Professional & scientific | 2016 |
| ATB Storage Limited | Other services | 2023 |
| Athanatic Ltd | Information & communication | 2022 |
| ATL Agri Limited | Professional & scientific | 2008 |
| ATL Agriserve Limited | Financial services | 2012 |
| Attracta Burns Healthcare Ltd | Health & social care | 2020 |
| Auction Smart Ltd | Wholesale & retail | 2024 |
| Augmented Audiences Limited | Information & communication | 2026 |
| August Farms LLP | | 2017 |
| Auntie Minas Ltd | Hospitality | 2024 |
| Auto Bridge Trading Limited | Wholesale & retail | 2025 |
| Automated Chilling and Freezing Limited | Manufacturing | 2015 |
| AV Consulting (MEA) Limited | Professional & scientific | 2015 |
| AV Engineer Limited | Professional & scientific | 2013 |
| Avance Bloodstock UK Ltd | Financial services | 2026 |
| Avenue Bloodstock Limited | Professional & scientific | 2017 |
| Aviation and Specialist Security Consultants Limited | Education | 2020 |
| Avican Support Ltd | Health & social care | 2006 |
| Avican Zipple Ltd | Health & social care | 2025 |
| Avis Decorators Ltd | Construction | 2015 |
| Avis Developers Ltd | Construction | 2026 |
| Avnex Limited | Manufacturing | 2001 |
| AZ Ltd | Extraterritorial | 2020 |
| Azantas Ltd | Wholesale & retail | 2018 |
| B & B Advertising Limited | Real estate | 1982 |
| B & B Building Contractors Limited | Construction | 2003 |
| B D S Electrical Limited | Manufacturing | 2003 |
| B G Europa (UK) Holding Company Limited | Professional & scientific | 2007 |
| B Z Alexander Limited | Professional & scientific | 2012 |
| B&B Management Limited | Financial services | 2020 |
| Babel Fish 42 Limited | Professional & scientific | 2022 |
| Badass 21 Ltd | Hospitality | 2022 |
| Badass Bites Ltd | Hospitality | 2018 |
| Badger Property Management Limited | Real estate | 2022 |
| Baker Mcveigh and Clements Limited | Professional & scientific | 2006 |
| Balaton Paddocks Ltd. | Construction | 2021 |
| Balaton Place Management Company Limited | Households | 2001 |
| Balea Ltd | Extraterritorial | 2019 |
| Balushi Motors Ltd | Wholesale & retail | 2020 |
| Bang Technologies Limited | Professional & scientific | 2021 |
| Banstead Manor Stud Limited(The) | Agriculture & fishing | 1925 |
| Baqi Community Welfare Limited | Education | 2025 |
| Bar Bar BSE Ltd | Hospitality | 2023 |
| Bar Import Ltd | Administrative & support | 2026 |
| Barberini Bloodstock Limited | Professional & scientific | 2014 |
| Bardwell DUN COW Ltd | Hospitality | 2024 |
| Barham & Moore Giving Ltd | Professional & scientific | 2025 |
| Barham Construction Ltd | Real estate | 2025 |
| Barker Equestrian Limited | Agriculture & fishing | 2023 |
| Baroda Stud Consigning Limited | Wholesale & retail | 2019 |
| BAS Electrical Contractor Ltd | Construction | 2014 |
| Batavia House Ltd | Wholesale & retail | 2019 |
| BB Translations Limited | Professional & scientific | 2016 |
| BBA Shipping & Transport Limited | Administrative & support | 2001 |
| BD Ltd | Extraterritorial | 2009 |
| BDS Technical Services Ltd | Professional & scientific | 2019 |
| BE Health Happier Ltd | Health & social care | 2024 |
| Beacon Tower Developments Limited | Real estate | 2016 |
| Beau Champ Retail Ltd | Wholesale & retail | 2018 |
| Beaufort Cottage Stables LLP | | 2014 |
| Beechgrove Property Management Limited | Real estate | 2022 |
| Befkamring Limited | Professional & scientific | 1987 |
| Bella Pubs 1 Ltd | Hospitality | 2024 |
| Bella Pubs 2 Ltd | Hospitality | 2024 |
| Bella Pubs 3 Ltd | Hospitality | 2025 |
| Bella Pubs Ltd | Hospitality | 2023 |
| Belmont Court (Newmarket) Limited | Real estate | 2010 |
| Benaldan Ltd | Real estate | 2015 |
| Bensen Holdings Limited | Professional & scientific | 2023 |
| Bensen Pharma Limited | Professional & scientific | 2023 |
| Bensen Therapeutics Limited | Professional & scientific | 2006 |
| Bentonite International Ltd | Wholesale & retail | 2024 |
| Berkshire Equine Limited | Professional & scientific | 2018 |
| Berto Solutions Ltd | Information & communication | 2019 |
| Bespoke Vehicle Solutions Limited | Wholesale & retail | 2025 |
| Beta - Alanine Limited | Professional & scientific | 2007 |
| Betta Beauty Limited | Health & social care | 2015 |
| Betterlate Publishing Ltd | Arts & recreation | 2025 |
| Bettor Equine Transport Ltd | Transport & logistics | 2025 |
| Bevan Electrical Services Ltd | Manufacturing | 2014 |