| Aqualarm Limited | Extraterritorial | 1988 |
| Arbscape Tree and Ground Ltd | Administrative & support | 2024 |
| Arca Trade Group Ltd | Transport & logistics | 2021 |
| Area 9 JDM Imports Ltd | Wholesale & retail | 2026 |
| Argenteum Solutions Limited | Professional & scientific | 2026 |
| Argy Asset Management Ltd | Administrative & support | 2017 |
| Argyle Way RMC Ltd | Households | 2021 |
| Arias Fine Dining Ltd | Hospitality | 2026 |
| Arishi Innovation Ltd | Information & communication | 2023 |
| ARK Business Consultancy Ltd | Professional & scientific | 2026 |
| Arkasian Property Management Limited | Real estate | 2007 |
| Arlis Cloud Ltd | Real estate | 2024 |
| Art and Craft Days Limited | Arts & recreation | 2014 |
| Artan Group International Ltd | Administrative & support | 2024 |
| Arteck Ltd | Information & communication | 2013 |
| Artillery Mews Resident Management Company Ltd | Households | 2024 |
| Artism Vista Ltd | Extraterritorial | 2022 |
| Asantify Ltd | Real estate | 2024 |
| ASB Technologies Ltd | Manufacturing | 2025 |
| Ascalon Building Services Limited | Construction | 2013 |
| Ascension Office Removal Services Limited | Transport & logistics | 2015 |
| Ashby a Collective Limited | Real estate | 2026 |
| Ashby a Holdings Limited | Financial services | 2026 |
| Ashingdon Hall Care Limited | Health & social care | 2007 |
| Ashley Knott Barbershop Limited | Other services | 2016 |
| Ashlyns Farm Shop & Restaurant Limited | Hospitality | 2017 |
| Ashton Financial Ltd | Professional & scientific | 2015 |
| Ashwell Label Dies Limited | Manufacturing | 1993 |
| Ashwood Housing Solutions CIC | Real estate | 2021 |
| Asia Design Limited | Information & communication | 2018 |
| Asksenti Ltd | Information & communication | 2015 |
| Asling Properties Limited | Administrative & support | 2009 |
| Aspire Bathrooms Essex Limited | Construction | 2025 |
| Asset Funder Limited | Financial services | 2015 |
| Assets and Investments Remuneration Ltd | Extraterritorial | 2011 |
| Assured Technologies Ltd | Construction | 2024 |
| Astrum Talent Limited | Administrative & support | 2025 |
| Athena Office Furniture Installations Ltd | Construction | 2015 |
| Athena Wills and Lasting Powers of Attorney Ltd | Professional & scientific | 2026 |
| Atkinsons Furniture and Appliances Ltd | Wholesale & retail | 2015 |
| Atlantic Tech Services Ltd | Other services | 2012 |
| ATM Spray Solutions Ltd | Manufacturing | 2014 |
| ATR Renewables Ltd | Construction | 2025 |
| Auctus PVT Ltd | Education | 2021 |
| Audley Mills Limited | Wholesale & retail | 2006 |
| Aurelynx Limited | Professional & scientific | 2025 |
| Aurum Brokers Limited | Financial services | 2026 |
| Authentic Essence Ltd | Professional & scientific | 2023 |
| Authentic HR Limited | Administrative & support | 2019 |
| Autoint Designs Ltd | Professional & scientific | 2024 |
| AVB Prestige Limited | Wholesale & retail | 2025 |
| Avendi Ventures Limited | Administrative & support | 2022 |
| Aventura Rock Ltd | Construction | 2022 |
| Avery & SON Ltd | Real estate | 2024 |
| Axestar Limited | Real estate | 2003 |
| Ayeyarwady Property Limited | Real estate | 2020 |
| Ayla Ann’S Property Ltd | Real estate | 2024 |
| Aylestone Avenue Limited | Construction | 2024 |
| AZ Wholesale Ltd | Wholesale & retail | 2017 |
| Aztec Marketing Ltd | Professional & scientific | 2021 |
| B & G Projects Ltd | Construction | 2022 |
| B C D C Limited | Administrative & support | 2005 |
| B J K Holding Ltd | Real estate | 2016 |
| B&N Copeland Consultancy Limited | Professional & scientific | 2019 |
| B2B Group Solutions Ltd | Administrative & support | 2022 |
| B71 Ltd | Real estate | 2025 |
| Baby Ballers Academy Limited | Arts & recreation | 2016 |
| Baby Sensory Basildon & Billericay Ltd | Education | 2015 |
| Back Property Holdings Ltd | Real estate | 2021 |
| Back to the Bases Ltd | Construction | 2020 |
| Bakecrate Limited | Hospitality | 2025 |
| Baker Blake Properties Limited | Real estate | 2026 |
| Baldwin Creative Ltd | Professional & scientific | 2025 |
| Ballingdon Limited | Real estate | 2003 |
| Balloons by Wonderland Limited | Wholesale & retail | 2004 |
| Bamfo Ltd | Public administration | 2020 |
| Bankhome Investments Ltd | Real estate | 2005 |
| Banned Ecomm Limited | Wholesale & retail | 2017 |
| Baobae Limited | Manufacturing | 2025 |
| Bar Terminus PUB Limited | Hospitality | 2024 |
| Barangreen Property Management Limited | Real estate | 1999 |
| Barber Salon Services Ltd | Wholesale & retail | 2019 |
| Barbercake Limited | Other services | 2025 |
| Barn Stoves & Fireplaces Limited | Wholesale & retail | 2025 |
| Barnes & Wells Property Maintenance Ltd | Professional & scientific | 2013 |
| Barnes & Wells Tree Care Ltd | Professional & scientific | 2024 |
| Barrett Estate and Letting Agents Limited | Real estate | 2005 |
| Barrett Estates Property Investments Ltd | Real estate | 2025 |
| Barretts Grove Management Limited | Real estate | 2016 |
| Bashford and Davies Estates Limited | Real estate | 2019 |
| Basildon Miniature Railway Ltd | Transport & logistics | 2024 |
| Bates & Miller Ltd | Real estate | 2024 |
| Battery Club Europe Limited | Wholesale & retail | 2023 |
| Battlesbridge Harbour LLP | | 2023 |
| Battlesbridge Tide Mill LLP | | 2023 |
| Battlions Ltd | Wholesale & retail | 2024 |
| Baugh Ltd | Construction | 2017 |
| Bauman Construction Ltd | Construction | 2018 |
| Baxter School of Motoring Limited | Education | 2014 |
| Bayer Group Ltd | Construction | 2026 |