| Ayah Hijab Ltd | Wholesale & retail | 2024 |
| Ayan ALI Limited | Wholesale & retail | 2026 |
| Ayat 5 Ltd | Wholesale & retail | 2018 |
| Ayda Deniz Ltd | Wholesale & retail | 2018 |
| Ayhan Devebacak Ltd | Wholesale & retail | 2025 |
| Ayling Developments Limited | Construction | 2025 |
| Aynur Ltd | Other services | 2019 |
| Aytoto Ltd | Wholesale & retail | 2024 |
| AZ Priime Mart Limited | Information & communication | 2026 |
| Azimax Trading Limited | Wholesale & retail | 1999 |
| Aziz BTL Properties Limited | Real estate | 2019 |
| Aziza Consultancy Limited | Other services | 2025 |
| Aztec Shows LLP | | 2003 |
| Azursic Ltd | Wholesale & retail | 2025 |
| Azwell Limited | Administrative & support | 2025 |
| Azyroai Ltd | Information & communication | 2025 |
| B & C Transport Limited | | 1990 |
| B & R Electrical Limited | Construction | 2005 |
| B C Healthyway Limited | Other services | 2020 |
| B D Sewell Ltd | Construction | 2009 |
| B F Ground Maintenance Limited | Administrative & support | 2008 |
| B G Property Maintenance Limited | Real estate | 1997 |
| B H Construction Services Limited | Construction | 2005 |
| B I Communications Limited | Manufacturing | 1983 |
| B I S Door Systems Limited | Construction | 1997 |
| B M Cooper & Co Limited | Professional & scientific | 2004 |
| B&A Brooder Properties UK Limited | Real estate | 2021 |
| B&B Cash and Carry Limited | Wholesale & retail | 2021 |
| B&V Installing Ltd | Administrative & support | 2016 |
| B. & M. Business Machines Limited | Wholesale & retail | 1971 |
| B. J. Phillips Limited | Wholesale & retail | 1981 |
| B.B. Grout Limited | Manufacturing | 1966 |
| B.B. Warehousing Limited | | 1984 |
| B.D.K. Publishing Ltd. | | 1990 |
| B.I.S. Solutions Limited | Information & communication | 2005 |
| B.J.C Decorating Limited | Construction | 2007 |
| B.K.F. Electrical Services Limited | Construction | 1994 |
| B.L. Wilson & Sons Limited | Wholesale & retail | 1979 |
| B.S. Haulage (UK) Limited | Arts & recreation | 1994 |
| B.T.N. Flooring Limited | Construction | 2006 |
| B.W. Fasteners Limited | Wholesale & retail | 1975 |
| B.W. Rice (Plant & Skip Hire) Limited | Other services | 1982 |
| B.W. Smith (Pledgdon Farms) Limited | Agriculture & fishing | 1960 |
| B2B Resources Limited | Other services | 2000 |
| BA Elsha Delight 2010 Limited | Hospitality | 2012 |
| Baak Services Limited | Administrative & support | 2010 |
| BABART20 Ltd | Wholesale & retail | 2025 |
| Baby Aizel Reyes Trader Ltd | Wholesale & retail | 2026 |
| BAC Catering Ltd | Hospitality | 2023 |
| Back 2 the Beat Ltd | Education | 2007 |
| Baddow Flooring Limited | Construction | 2002 |
| Baddow Plumbing Services Limited | Construction | 2001 |
| Badger Tree Ltd | Information & communication | 2023 |
| Baghdad Barber Shop Limited | Other services | 2006 |
| Bagus Shop Ltd Ltd | Wholesale & retail | 2023 |
| Bahara Designs Ltd | Professional & scientific | 2002 |
| Bahkhrani Group of Companies Limited | Professional & scientific | 2024 |
| Baige UK Limited | Health & social care | 2016 |
| Bailes & Kidley Limited | Construction | 1974 |
| Baillie Business Supplies Ltd | Wholesale & retail | 2004 |
| Baker-Barnard Engineering Co Limited | Wholesale & retail | 1963 |
| BAL Medicals Limited | Health & social care | 2023 |
| Balanced Life Therapy Centre Limited | Wholesale & retail | 2006 |
| Baldock Car Valeting Ltd | Wholesale & retail | 2022 |
| Baldry Brothers Holding Ltd | Financial services | 2026 |
| Balkerne Tower Trust Limited | Arts & recreation | 2006 |
| Balmoral Group Limited | Real estate | 2017 |
| Balmoral Homes U.K. Limited | Construction | 2000 |
| Baltra Investments Limited | Real estate | 1973 |
| Bambus Properties Limited | Real estate | 2024 |
| Bamforth Management Limited | Professional & scientific | 2005 |
| Bamrah Property Ltd | Real estate | 2024 |
| Bancroft Court Limited | Real estate | 1985 |
| Bancroft's School | Education | 1998 |
| Band Post Limited | Wholesale & retail | 2002 |
| Bapa Care Homes & Youth Engagement Services Ltd | Hospitality | 2023 |
| Baraka Food Distribution Ltd | Wholesale & retail | 2023 |
| Barclay Finance (Woodford) Company Limited | Professional & scientific | 2002 |
| Barileva Limited | Wholesale & retail | 2018 |
| Barking and Dagenham Youth Dance Limited | Arts & recreation | 2005 |
| Barking Park Hotel Limited | Hospitality | 2003 |
| Barkingside Islamic Cultural Centre & Mosque | Other services | 2023 |
| Barkins Butchers Limited | Wholesale & retail | 2003 |
| Barlow Tyrie Limited | Manufacturing | 1956 |
| Barm Agro Limited | Wholesale & retail | 2025 |
| Barmark Reinforcement Limited | Construction | 2005 |
| Barn Nursery (Thaxted) Limited | Education | 2002 |
| Barri Dess Ltd | Wholesale & retail | 2026 |
| Barrier Air Conditioning Limited | Construction | 1983 |
| Barrier Components Limited | Wholesale & retail | 1987 |
| Barrington Place Developments Limited | Real estate | 2005 |
| Barrow Hazell & Company Ltd | Financial services | 1999 |
| Barry Foley Developments Ltd | Construction | 2003 |
| Barry's Locks Limited | Construction | 1993 |
| Barseagle Limited | Professional & scientific | 2021 |
| Bartalls & Company Limited | Real estate | 1992 |
| Bartholomew House Management Ltd | Households | 2022 |
| Barton Timber Company Limited | Manufacturing | 1945 |
| Base Design Ltd | Manufacturing | 2007 |
| BASE2 Concept Design Make Limited | Construction | 2004 |