| ASN Decoration Ltd | Construction | 2017 |
| Aspect Compliance Ltd | Professional & scientific | 2026 |
| Aspect Installations Limited | Construction | 2006 |
| Aspire Day Nursery Ltd | Health & social care | 2024 |
| Asrb Consulting Ltd | Information & communication | 2023 |
| Assured Health and Safety Ltd | Administrative & support | 2016 |
| Asteetva Corporation Ltd | Wholesale & retail | 2019 |
| Astley & Meslet Ltd | Professional & scientific | 2024 |
| Astraguard Systems Limited | Information & communication | 2009 |
| ATA International Turkish Kitchen Ltd | Hospitality | 2024 |
| Atacama Investments Limited | Financial services | 2025 |
| Atelier Hockey Ltd | Professional & scientific | 2019 |
| Atelier Nine Ltd | Wholesale & retail | 2026 |
| Atlex Ltd | Agriculture & fishing | 2024 |
| Atma Logistics Ltd | Transport & logistics | 2021 |
| Atom 77 Limited | Professional & scientific | 2016 |
| Atom Connect Limited | Education | 2025 |
| Attain Accountancy Ltd | Professional & scientific | 2023 |
| Audiology Solutions Ltd | Health & social care | 2023 |
| Auditshield Limited | Information & communication | 2026 |
| Audley Bennett Ltd | Transport & logistics | 2009 |
| Audrey Dennis Consulting Limited | Real estate | 2012 |
| Augustus Data Ltd | Information & communication | 2015 |
| Aura Distribution and Technology LLP | | 2010 |
| Aura Green Consultancy Ltd | Administrative & support | 2024 |
| Aurasys Ltd | Information & communication | 2018 |
| Aurora Foundation for People Abused in Childhood Ltd | Health & social care | 2006 |
| Auto Haven Ltd | Wholesale & retail | 2018 |
| Autokeylab Ltd | Wholesale & retail | 2026 |
| Auxilium Business Consulting Ltd | Administrative & support | 2016 |
| Avalon Foxrock Limited | Real estate | 2021 |
| Avens House Surbiton Freehold Ltd | Real estate | 2012 |
| Avenue Sixty Limited | Households | 2016 |
| Averox Pluto Ltd | Wholesale & retail | 2012 |
| Aviate First Limited | Professional & scientific | 2009 |
| AVK Estates Ltd | Real estate | 2023 |
| AVK Insights Ltd | Information & communication | 2025 |
| AVK Tutors Ltd | Education | 2019 |
| Avteamuk Ltd | Other services | 2016 |
| Avus Estates Limited | Construction | 2026 |
| AW SW16 Limited | Hospitality | 2021 |
| Awan Heating, Plumbing and Bathroom Specialist Limited | Wholesale & retail | 2009 |
| AWL Property Services Limited | Construction | 2013 |
| Awrad Limited | Health & social care | 2020 |
| Axcelerant Group Limited | Professional & scientific | 1996 |
| Axecellent Solutions Ltd | Information & communication | 2024 |
| Axior Consulting Limited | Professional & scientific | 2017 |
| AYA Driving Services Ltd | Other services | 2017 |
| Aylesbury Fish&Chips Limited | Hospitality | 2026 |
| AZ Comunication Ltd | Information & communication | 2019 |
| AZ GTR Solutions Ltd | Wholesale & retail | 2026 |
| Azure Corporate Finance Limited | Professional & scientific | 2025 |
| Azure Itsm Limited | Information & communication | 2016 |
| Azure PH Ltd | Professional & scientific | 2008 |
| B & S Build Limited | Construction | 2025 |
| B Chohan Consultancy Services Ltd | Real estate | 2021 |
| B&V Property Limited | Real estate | 2026 |
| B'Nai B'Rith United Kingdom | Other services | 1997 |
| B.F.S.C. Ltd | Real estate | 2009 |
| B17 Preservation Limited | Extraterritorial | 1983 |
| BA Immigration Ltd | Professional & scientific | 2022 |
| Babahouse Ltd | Financial services | 2025 |
| Back in Time Event Ltd | Arts & recreation | 2024 |
| Badminton Management Limited | Households | 1981 |
| Baikie Clothing Co Ltd | Manufacturing | 2021 |
| Baila Limited | Information & communication | 2006 |
| Baker Hamilton Associates Ltd | Real estate | 2025 |
| Baker Hamilton Ltd | Information & communication | 2022 |
| Baker Hamilton Partners Ltd | Real estate | 2025 |
| Bali K Construction Ltd | Construction | 2022 |
| Bali Renovations Ltd | Construction | 2025 |
| Balloon Brands Ltd | Administrative & support | 2022 |
| Balmain Lodge Limited | Households | 1987 |
| Balsingbad Ltd | Real estate | 2025 |
| BAM Real Estate Limited | Real estate | 2025 |
| BAM Technology Solutions Limited | Information & communication | 2025 |
| Bamanoosh Persian Grill Kitchen Ltd | Hospitality | 2022 |
| Bangla Shoppers Ltd | Wholesale & retail | 2021 |
| Bankside Close Freehold Company Limited | Households | 2012 |
| Bankside Close Management Company | Households | 1969 |
| Bans IT Services Ltd | Information & communication | 2022 |
| Bapei Consulting Limited | Information & communication | 2019 |
| Bar None Leisure Consultancy Ltd | Professional & scientific | 2021 |
| Bargain Bridges Limited | Wholesale & retail | 2023 |
| Barleywood Trading Ltd | Wholesale & retail | 2024 |
| Barnings Ltd | Information & communication | 2018 |
| Barnold Post Ltd | Administrative & support | 2016 |
| Barrack Properties Ltd | Real estate | 2023 |
| Barry Sawyer Limited | Administrative & support | 2007 |
| Bart Films Ltd | Information & communication | 2020 |
| Barukh Properties Ltd | Real estate | 2021 |
| BAS & PMS Consulting Ltd | Information & communication | 2019 |
| Baseline Property Investments Limited | Real estate | 2019 |
| Basics of Business Limited | Information & communication | 2023 |
| Basil Gondal Ltd | Transport & logistics | 2017 |
| Basil Gondal Properties Ltd | Real estate | 2025 |
| Bassbray Management (Malden Court) Limited | Households | 1976 |
| BAT Comms Consultancy Ltd | Professional & scientific | 2017 |
| Bath Stuff Limited | Manufacturing | 2023 |
| Batterfly Kitchen Ltd | Hospitality | 2025 |