| Aston Create & Design Limited | Administrative & support | 2015 |
| Astons Building Services Limited | Extraterritorial | 2013 |
| Astons Facilities Management Limited | Administrative & support | 2013 |
| Astrokid Studios Ltd | Information & communication | 2024 |
| Astrum Technology Ltd | Construction | 2016 |
| AT Elevate Entertainment Ltd | Professional & scientific | 2025 |
| AT the POP Limited | Administrative & support | 2012 |
| AT Work Films Ltd. | Information & communication | 2012 |
| ATA EGE Yachting London Limited | Administrative & support | 2022 |
| Ates Turkish Kitchen Ltd | Hospitality | 2025 |
| Atfirstsite App Ltd | Information & communication | 2021 |
| ATH Training South Essex Ltd | Education | 2025 |
| Athespian Theatre Company Ltd | Education | 2026 |
| Athrach Ltd | Information & communication | 2025 |
| ATK Associates Limited | Real estate | 2016 |
| Atkins Management Services Ltd | Professional & scientific | 2017 |
| ATL Safety Limited | Professional & scientific | 2011 |
| Atlant Group Ltd | Real estate | 2022 |
| Atlas Massage Therapy Ltd | Other services | 2021 |
| ATM Facilities Ltd | Construction | 2017 |
| Atmaca Essex Ltd | Hospitality | 2024 |
| Atozql Research Limited | Information & communication | 2026 |
| ATS Accounting Limited | Professional & scientific | 2007 |
| Attadale Property Limited | Real estate | 2016 |
| Auction House (Abridge) Management Company Limited | Real estate | 2022 |
| Audley Homes (Frinton Manor) Limited | Construction | 2013 |
| Augustyn Consulting Limited | Professional & scientific | 2025 |
| Aura Grill London Limited | Hospitality | 2023 |
| Aura IT Solutions Limited | Information & communication | 2016 |
| Aura Naturals Ltd | Wholesale & retail | 2025 |
| Aurele Medical Limited | Health & social care | 2025 |
| Aurelius Executive Protection Ltd | Administrative & support | 2022 |
| Aurelius Property Group Ltd | Real estate | 2026 |
| Auris Management Limited | Construction | 2014 |
| Aurous Pizza Holdings Limited | Financial services | 2023 |
| Aurum Consultancy Ltd | Professional & scientific | 2025 |
| Aurum Contracts Limited | Construction | 2018 |
| Aurum Drainage Limited | Water & waste | 2026 |
| Austin Interiors Services Ltd | Construction | 2018 |
| Austingracesuk Limited | Health & social care | 2006 |
| Auto Repair Centre (Loughton) Ltd | Wholesale & retail | 2011 |
| Autofrench Limited | Wholesale & retail | 2022 |
| Av.Fixbuilding Ltd | Construction | 2023 |
| AVA Capital (Luton) Limited | Real estate | 2023 |
| AVA Capital (Maidstone) Limited | Real estate | 2024 |
| AVA Capital Construction Limited | Construction | 2025 |
| AVA Capital Limited | Real estate | 2021 |
| AVA Medical Limited | Administrative & support | 2025 |
| AVA Produce Limited | Wholesale & retail | 2010 |
| Avastora Limited | Wholesale & retail | 2025 |
| Avcl Asset Consultants Limited | Professional & scientific | 2023 |
| Avenir Investments Limited | Real estate | 2004 |
| Avenue East Limited | Administrative & support | 2016 |
| Avenue Osteopaths Limited | Health & social care | 2016 |
| Averroes Ventures Advisory Ltd | Financial services | 2024 |
| Averyrwalsh Ltd | Arts & recreation | 2022 |
| Avian Finance Limited | Real estate | 1964 |
| Avoncliffe Investments Ltd | Real estate | 2020 |
| Avoncliffe Properties Ltd | Real estate | 2019 |
| AVP Ventures Ltd | Administrative & support | 2007 |
| AVS Contracts Ltd | Construction | 2025 |
| Awaiting Press Limited | Information & communication | 2021 |
| AXE Holdings Management Limited | Financial services | 2024 |
| AXE Regen Limited | Construction | 2026 |
| AXE Roofing Ltd | Construction | 2020 |
| AXE Wealth Limited | Other services | 2024 |
| Axeva Partners Limited | Administrative & support | 2011 |
| Axrc Interiors Ltd | Construction | 2024 |
| AXS Global Limited | Administrative & support | 2023 |
| Ayla & Maya Ltd | Wholesale & retail | 2025 |
| Aylwin Projects Ltd | Professional & scientific | 2020 |
| Aysgarth Properties Limited | Real estate | 2000 |
| Aysgarth Services Limited | Administrative & support | 2016 |
| AZN Trading Ltd | Hospitality | 2020 |
| B &S Homeworks Ltd | Construction | 2025 |
| B Morgan Roofing Limited | Construction | 2019 |
| B Patient Tiling Ltd | Construction | 2009 |
| B T Catering Services Limited | Hospitality | 2024 |
| B&G Homecare Services Ltd | Construction | 2026 |
| B&H Garden Properties Limited | Real estate | 2024 |
| B&P Cleaner Ltd | Administrative & support | 2026 |
| B&S Beauty Bliss Ltd | Other services | 2012 |
| B-Next Limited | Wholesale & retail | 2012 |
| B. DYE Driving Services Limited | Other services | 2017 |
| B.R.A.K.A.A Estate Ltd | Real estate | 2021 |
| B.T.B. Nottingham Ltd | Construction | 2012 |
| BA Powersuite Ltd | Information & communication | 2026 |
| Babish Kitchen Ltd | Hospitality | 2025 |
| Bacarel & Co Group Holdings Limited | Financial services | 2018 |
| Bacarel & Co Holdings Limited | Professional & scientific | 1998 |
| Bacarel and Co. Limited | Wholesale & retail | 1984 |
| Bafio Ltd | Hospitality | 2019 |
| Bailey Brothers Interiors Limited | Construction | 2017 |
| Baines Commercial Cleaning Ltd | Administrative & support | 2021 |
| Bajanize Ltd | Hospitality | 2022 |
| Baker ST 79 Limited | Other services | 2022 |
| Bakers Coffee Ltd | Hospitality | 2025 |
| Bala Plumbing & Heating Ltd | Construction | 2024 |
| Balansin Limited | Construction | 2017 |
| Balbes Hair Design Ltd | Other services | 2026 |