| Anhem Ltd | Hospitality | 2026 |
| Annsons Limited | Extraterritorial | 2007 |
| Aoxomedia Limited | Information & communication | 2018 |
| Apex Security Engineering Limited | Manufacturing | 1992 |
| Apex Security Furniture Limited | Extraterritorial | 2003 |
| Apple HR Ltd | Professional & scientific | 2005 |
| Applied Medical Technology Limited | Wholesale & retail | 1998 |
| Applied Polymer Supplies Limited | Wholesale & retail | 2025 |
| Appsbyme Limited | Information & communication | 2014 |
| Apsa Retail Ltd | Wholesale & retail | 2025 |
| APT and Able Limited | Transport & logistics | 2015 |
| AR Heating & Plumbing Ltd | Construction | 2024 |
| Arbour Partners LLP | | 2010 |
| ARC Heating Limited | Construction | 2017 |
| Arcalis Services Limited | Information & communication | 2018 |
| Archer Davies Limited | Information & communication | 2026 |
| Archipelago Brand Consulting Ltd | Professional & scientific | 2013 |
| Archos Properties Ltd | Construction | 2019 |
| Argyle One Ltd. | Information & communication | 2017 |
| Art Lapis LLP | | 2015 |
| Artefact Creative Ltd | Information & communication | 2017 |
| Artema Productions Limited | Information & communication | 2017 |
| AS Bathrooms Ltd | Construction | 2016 |
| ASH Carpenters Limited | Construction | 2008 |
| Ashbrook (2017) Management Company Limited | Households | 2017 |
| Asher Electrical Ltd | Construction | 2024 |
| ASO Property Services (UK) Limited | Extraterritorial | 1993 |
| Aspect Critical Holdings Ltd | Financial services | 2023 |
| Aspect Critical Power Logistics Ltd | Transport & logistics | 2023 |
| Aspect Electrical Limited | Construction | 2003 |
| Aspect Property Developments Limited | Construction | 2016 |
| Aspire Analysis Ltd | Wholesale & retail | 2025 |
| Asset and Frontline Security Services Ltd | Administrative & support | 2020 |
| Asset Residual Management Limited | Wholesale & retail | 2011 |
| Asterisk Media Productions Ltd. | Information & communication | 2019 |
| Atab Properties Limited | Real estate | 2018 |
| Atlantis Plumbing Company Limited | Construction | 2006 |
| Atlas Horizon Travel Limited | Administrative & support | 2026 |
| Auburn Training Ltd | Construction | 2010 |
| Audacious Productions Ltd | Information & communication | 2018 |
| Audio Outpost Ltd | Manufacturing | 2017 |
| Audio Shop UK Ltd | Wholesale & retail | 2018 |
| Auslar Consulting Limited | Professional & scientific | 2025 |
| Avaruus Limited | Construction | 2016 |
| Avebury Alternative Capital Limited | Other services | 2010 |
| Aviate Global Ltd | Administrative & support | 2024 |
| Avsync Media Limited | Information & communication | 2026 |
| Axis Mundi Ltd | Energy | 2017 |
| Axis RDB Limited | Construction | 2009 |
| Axismicrogen Ltd | Construction | 2011 |
| Axmint Ltd | Extraterritorial | 2015 |
| Axudar Care Limited | Health & social care | 2023 |
| Axudar Group Limited | Professional & scientific | 2026 |
| Axudar Health Limited | Health & social care | 2023 |
| Axudar Healthcare Limited | Health & social care | 2023 |
| Axudar Learning Ltd | Education | 2024 |
| Axudar Limited | Health & social care | 2023 |
| Axudar Medical Limited | Health & social care | 2023 |
| Ayrton Christie Limited | Financial services | 2021 |
| Azonic Solutions Limited | Manufacturing | 2007 |
| B & C Doors Limited | Water & waste | 2004 |
| B Mcelwee Carpentry & Joinery Ltd | Manufacturing | 2022 |
| B2B Baits Limited | Wholesale & retail | 2017 |
| BA Roofing Limited | Construction | 2017 |
| Babam Barbers Ltd | Other services | 2019 |
| Back to Reality Productions Limited | Information & communication | 2025 |
| Bacon Cake Ltd | Hospitality | 2014 |
| BAD George Ltd | Arts & recreation | 2024 |
| BAH OUI Films Ltd | Information & communication | 2021 |
| Ballard and Tucker Limited | Health & social care | 2000 |
| Ballerina Sparkle Daddy Ltd | Arts & recreation | 2025 |
| Balnalick Ltd | Agriculture & fishing | 2021 |
| Banana & Byte Design Ltd | Information & communication | 2026 |
| Barefoot & Board Ltd | Real estate | 2025 |
| Barker Bespoke Limited | Manufacturing | 2026 |
| Barnet Marketing Limited | Information & communication | 2020 |
| Barry's Economics Ltd | Information & communication | 2026 |
| Base and Flow Ltd | Information & communication | 2026 |
| Basecore Limited | Professional & scientific | 2026 |
| BAW Civils Ltd | Construction | 2025 |
| Bazaar Velvet Limited | Wholesale & retail | 2007 |
| Baziram Ltd | Transport & logistics | 2018 |
| Beagle Creative Limited | Administrative & support | 2020 |
| Beagle Holdings Limited | Financial services | 2024 |
| Beaumont Newsagency Limited | Wholesale & retail | 2023 |
| Beba Foods Ltd | Hospitality | 2021 |
| Bedford Steam Engine Club Limited | Arts & recreation | 1985 |
| Bedfordshire Ventilation Services Ltd | Professional & scientific | 2024 |
| Bedlam Street Ltd | Information & communication | 2021 |
| Belal’S Holdings Limited | Wholesale & retail | 2026 |
| Belgrove Associates Limited | Professional & scientific | 2024 |
| Bell Tailors Limited | Wholesale & retail | 2016 |
| BEN E Branch Ltd | Construction | 2015 |
| BEN Jones Roofing Ltd | Construction | 2025 |
| BEN Tuck Racing Limited | Arts & recreation | 2015 |
| Bergamoo Limited | Professional & scientific | 2018 |
| Bergdorfs Flowers of Copenhagen Limited | Wholesale & retail | 2013 |
| Bermondsey Exchange Freeholders Limited | Real estate | 2009 |
| Bessimer Limited | Financial services | 2022 |
| Best Residential Limited | Real estate | 2005 |