| Archees Limited | Real estate | 2024 |
| Arclo Properties Ltd | Real estate | 2018 |
| Ardentsys Ltd | Information & communication | 2008 |
| Argohurst Limited | Other services | 1982 |
| Ari-Ari Ltd | Professional & scientific | 2025 |
| Aria Design Studios Ltd | Arts & recreation | 2025 |
| Arikaenterprisesuk Ltd | Wholesale & retail | 2023 |
| Aris Distributor Ltd | Other services | 2020 |
| Arlon Contractor Ltd | Construction | 2026 |
| Armared Ltd | Real estate | 2019 |
| Arrogant Pixel Ltd | Information & communication | 2015 |
| Artesania Ltd | Hospitality | 2025 |
| Artkitrave Ltd | Administrative & support | 2020 |
| Arts & Antiques Stewarship Ltd | Education | 2026 |
| Asen Ltd | Construction | 2016 |
| ASF Capital Limited | Professional & scientific | 2023 |
| Asguard London Protection Services Limited | Administrative & support | 2018 |
| ASH Sanctuaire Limited | Other services | 2020 |
| Ashgrove TW151NU Ltd | Households | 2023 |
| Asmarina Smile Limited | Health & social care | 2019 |
| Aspen IT and Media Solutions Ltd | Information & communication | 2021 |
| Aston Webb & Company Limited | Construction | 2013 |
| AT Business Services Limited | Professional & scientific | 2004 |
| Atithi Indian Cuisine Ltd | Extraterritorial | 2010 |
| Atlantisforyou Ltd | Wholesale & retail | 2017 |
| Attractive Features Ltd | Information & communication | 1997 |
| Augment Technologies Ltd | Information & communication | 2017 |
| Aulic Limited | Hospitality | 2025 |
| Aung Property Management Ltd | Real estate | 2026 |
| Aupra Ltd | Wholesale & retail | 2019 |
| Aureum Advocacy Ltd | Professional & scientific | 2026 |
| Aurora: European Services Limited | Professional & scientific | 2010 |
| Aurumindo Land Investment Ltd | Extraterritorial | 2020 |
| Auto Experience Ltd | Wholesale & retail | 2025 |
| Autoanalysis Limited | Professional & scientific | 1996 |
| Automatic Power Ltd | Manufacturing | 2002 |
| Automation & Control Engineering Limited | Other services | 2006 |
| Avaris Property Ltd | Real estate | 2021 |
| Aviso Microcad Solutions Ltd. | Professional & scientific | 2015 |
| Aviso Technologies Ltd | Information & communication | 2025 |
| AZ Assessment Centre Limited | Education | 2016 |
| Azjem Ltd | Extraterritorial | 2018 |
| Azmorah Ltd | Wholesale & retail | 2026 |
| B M Best Solutions Ltd | Other services | 2021 |
| B&S Auto Refinishing Ltd | Construction | 2016 |
| B2B Radio Limited | Information & communication | 2021 |
| BA Stark Plumbing and Heating Ltd | Construction | 2017 |
| BA3I Ltd | Real estate | 2019 |
| Backstage Makeup Studio & Care Ltd | Professional & scientific | 2020 |
| Bacon Business Limited | Professional & scientific | 2025 |
| Baiano Co. Ltd | Hospitality | 2021 |
| Bako Zero 8 Ltd | Extraterritorial | 2018 |
| Bali Property Ltd | Real estate | 2024 |
| Balrog Technology Limited | Other services | 2018 |
| Bambu Peak Ltd | Real estate | 2017 |
| Bang Bang Herbal Ltd | Wholesale & retail | 2025 |
| Barie Ltd | Real estate | 2019 |
| Bark Coffee Ltd | Hospitality | 2020 |
| Barnes Investments Ltd | Real estate | 2016 |
| Barry Executives Limited | Construction | 2012 |
| Barson Daisy Property Ltd | Real estate | 2019 |
| Base Scaffolding UK Limited | Construction | 2007 |
| Basecamp Investments Ltd | Real estate | 2019 |
| Basement Contractors London Ltd | Construction | 2019 |
| Bash Ltd | Hospitality | 2009 |
| Bayside Homes Ltd | Real estate | 2016 |
| BCM Property Investments Ltd | Real estate | 2019 |
| BDS Sanctuary Limited | Real estate | 2019 |
| Bean Properties Ltd | Real estate | 2018 |
| Bearbox International Limited | Administrative & support | 2006 |
| Beauty.M Ltd | Other services | 2014 |
| Behzad Transport Ltd | Transport & logistics | 2026 |
| Bella Union Limited | Information & communication | 1996 |
| Bella Union Songs Ltd | Information & communication | 2012 |
| Bellamie Foods PVT Ltd | Manufacturing | 2022 |
| BEN Exley Ltd | Information & communication | 2020 |
| Benwildephysio Ltd | Health & social care | 2024 |
| Berc Trading Ltd | Professional & scientific | 2026 |
| BERG321 Limited | Other services | 2018 |
| Berkeley House Management (Hampton) Limited | Households | 1976 |
| Berkshire Consultancy Holdings Limited | Professional & scientific | 2013 |
| Berkshire Consultancy Limited | Professional & scientific | 1985 |
| Berkshire Consultancy Trustee Limited | Other services | 2023 |
| Berkshire Floors Ltd | Wholesale & retail | 2025 |
| Berserk Systems Ltd. | Extraterritorial | 2019 |
| Bessells Green Investment Co.Limited | Real estate | 1955 |
| Bestlevel Limited | Administrative & support | 2016 |
| Bethel International Ltd | Real estate | 2018 |
| Better Deals Commerce Ltd | Wholesale & retail | 2023 |
| Betul Balci Therapy Ltd | Health & social care | 2024 |
| Beyond Properties Ltd | Real estate | 2019 |
| Beyond Rehab Limited | Professional & scientific | 2025 |
| Bhatia Diagnostic Imaging Limited | Health & social care | 2017 |
| Bikemastersuk Ltd | Wholesale & retail | 2018 |
| Bility Ltd | Professional & scientific | 2020 |
| Billion Elite Holdings Limited | Real estate | 2017 |
| Bimedge Studios Ltd | Professional & scientific | 2025 |
| Birdie Bikes Ltd | Wholesale & retail | 2011 |
| Bistep Ltd | Extraterritorial | 2016 |
| Black Mountain Consultants Ltd | Professional & scientific | 2025 |