| Arshad Chaiwala Ltd | Hospitality | 2026 |
| Art E Pasta Ltd | Hospitality | 2025 |
| Artefacts to Order Limited | Wholesale & retail | 2021 |
| Artfab Solutions Ltd | Manufacturing | 2022 |
| Arthouse Crouch END Ltd | Information & communication | 2026 |
| Arttach Ltd | Professional & scientific | 2025 |
| Arura Analytics Ltd | Information & communication | 2018 |
| Arura Assets Ltd | Real estate | 2025 |
| Arura Group Ltd | Wholesale & retail | 2016 |
| ARV Contractors Ltd | Construction | 2023 |
| ARY Digital Network Limited | Information & communication | 2023 |
| Aryana Builders Ltd | Construction | 2019 |
| AS Security Limited | Administrative & support | 2015 |
| AS Skillsecure Ltd | Education | 2025 |
| AS Wealth Management Limited | Financial services | 2014 |
| Asap Pro Mobile Tyre Ltd | Wholesale & retail | 2026 |
| Asaz Consulting Ltd | Information & communication | 2020 |
| ASC Plumstead Limited | Education | 2019 |
| Ascend Ventures Limited | Real estate | 2023 |
| Asgroup Ltd | Other services | 2009 |
| Ashabi's Rode Limited | Wholesale & retail | 2024 |
| Ashara Properties Limited | Real estate | 2017 |
| Ashley Technology Ltd | Wholesale & retail | 2025 |
| Ashvalen Ltd | Professional & scientific | 2025 |
| Asian Feast Ltd | Hospitality | 2025 |
| ASILOMAR22 Ltd | Health & social care | 2023 |
| Asms Trades Ltd | Construction | 2026 |
| ASP1 Logistics Ltd | Transport & logistics | 2025 |
| Assured Care Place Limited | Administrative & support | 2022 |
| Assured Facilities Services Limited | Professional & scientific | 2004 |
| Aston Morgan Motors Ltd | Wholesale & retail | 2026 |
| Astute UK Partners Limited | Administrative & support | 2007 |
| Atlantic Edge Property Investments Limited | Real estate | 2021 |
| Atlantic Fish (Wholesale) Limited | Wholesale & retail | 1971 |
| Atlantic Freight (UK) Ltd | Transport & logistics | 2014 |
| Atlas Bond Resources Ltd | Health & social care | 2025 |
| ATM Equipment Hire Ltd | Administrative & support | 2022 |
| Atreo Limited | Professional & scientific | 2016 |
| Auge Ltd | Construction | 2022 |
| Auri Builders Ltd | Construction | 2023 |
| Aurora Brewing Limited | Manufacturing | 2011 |
| Autexa Drive Ltd | Wholesale & retail | 2015 |
| Auto Car Club Ltd | Wholesale & retail | 2025 |
| Auto Wixu Limited | Wholesale & retail | 2016 |
| Auto Wonderland Limited | Wholesale & retail | 2023 |
| Autocred Ltd | Wholesale & retail | 2025 |
| Automatic Gearbox Engineering Limited | Wholesale & retail | 2017 |
| Autosuporta Ltd | Professional & scientific | 2010 |
| Autotreidas Limited | Wholesale & retail | 2020 |
| Autotrust Ltd | Wholesale & retail | 2020 |
| Avansa IT Solutions Ltd | Information & communication | 2022 |
| Avensis Plus Ltd | Professional & scientific | 2015 |
| Averix Advisory Ltd | Administrative & support | 2025 |
| Avilion Limited | Professional & scientific | 1989 |
| Avion Homes Limited | Construction | 2022 |
| Avis Property Development Ltd | Real estate | 2025 |
| Avodha Consulting Ltd | Information & communication | 2025 |
| Avonra Natural Ltd | Wholesale & retail | 2017 |
| Awo-Solve Limited | Professional & scientific | 2014 |
| AX Drives Ltd | Transport & logistics | 2023 |
| AY Homes Investment Ltd | Construction | 2024 |
| Ayana Holdings Limited | Wholesale & retail | 2020 |
| Ayat London Ltd | Transport & logistics | 2015 |
| Ayisha's Nursin and Care Ltd | Health & social care | 2022 |
| Aypex Construction Ltd | Construction | 2025 |
| Ayztech IT Solutions Limited | Information & communication | 2021 |
| AZ Commerce Group Ltd | Wholesale & retail | 2024 |
| AZ Finance Property Ltd | Real estate | 2025 |
| AZB Invest Limited | Transport & logistics | 2023 |
| Azsu Limited | Hospitality | 2018 |
| Azure Business Analytics Limited | Information & communication | 2023 |
| AZZ Global Private Ltd | Wholesale & retail | 2025 |
| B & P Scrap Co. Limited | Water & waste | 2005 |
| B & Sons Holdings Ltd | Financial services | 2023 |
| B E Castle Ltd | Health & social care | 2023 |
| B H H J Construction Ltd | Construction | 2018 |
| B M D Express Ltd | Transport & logistics | 2015 |
| B&J Bamise Limited | Health & social care | 2023 |
| B&K Multiservices Ltd | Professional & scientific | 2017 |
| B&M Auto Limited | Wholesale & retail | 2025 |
| B&T Auto Traders Ltd | Wholesale & retail | 2023 |
| B-Swift Facilities UK Ltd | Administrative & support | 2015 |
| BAA (Essex) Ltd | Education | 2024 |
| BAC (Essex) Ltd | Other services | 2018 |
| Bacchus Investors Limited | Financial services | 2021 |
| Baddoo Holdings Ltd | Real estate | 2025 |
| Baddoo Management Ltd | Real estate | 2025 |
| Baddoo Motors Ltd | Wholesale & retail | 2019 |
| Baddoo Services Ltd | Wholesale & retail | 2022 |
| Badmus & Badmus Global Resources Ltd | Transport & logistics | 2025 |
| Bains K Properties Ltd | Real estate | 2025 |
| Bajelis Limited | Wholesale & retail | 2024 |
| Bakre Medical Associates Limited | Other services | 2018 |
| Bala Food Service Ltd | Wholesale & retail | 2024 |
| Bala Wholesale Express Ltd | Wholesale & retail | 2020 |
| Bala Wholesale Limited | Wholesale & retail | 2025 |
| Bala Wholesalers Limited | Wholesale & retail | 2021 |
| Baldock Tyres Ltd | Wholesale & retail | 2000 |
| Balmond Wholefoods Ltd | Wholesale & retail | 2022 |
| BAM MK Limited | Administrative & support | 2012 |