| Aziela Limited | Information & communication | 2019 |
| Azur Homes Limited | Construction | 2021 |
| Azura Cloud Systems Ltd | Information & communication | 2009 |
| B & B Property Holdings Ltd | Real estate | 2019 |
| B & S Media Limited | Financial services | 2018 |
| B D C Homes Limited | Construction | 1993 |
| B H N Property Ltd | Real estate | 2023 |
| B-Yond Rehab Limited | Health & social care | 2019 |
| B.A. Yeowart Holdings Limited | Agriculture & fishing | 1956 |
| B4IGO.AI Ltd | Information & communication | 2023 |
| B4ND Ltd | Education | 2024 |
| Bachata FIX Ltd | Arts & recreation | 2019 |
| Bacterzyme Global Ltd | Manufacturing | 2024 |
| Badminton Estates Limited | Real estate | 2002 |
| Badminton Estates Property LLP | | 2008 |
| BAF Solutions Limited | Information & communication | 2004 |
| Bagdock Limited | Information & communication | 2025 |
| Bahru Films Ltd | Information & communication | 2017 |
| Baigify Ltd | Wholesale & retail | 2025 |
| Bailey Roofing & Property Services Ltd | Construction | 2023 |
| Baileyfields Solicitors Limited | Professional & scientific | 2004 |
| Baker and Page Limited | Administrative & support | 2015 |
| Baker Moult Consulting Limited | Professional & scientific | 1987 |
| Baker Wilcox Ltd | Professional & scientific | 2005 |
| Bakers Betting Limited | Real estate | 2015 |
| Balanced Accounting LLP | | 2008 |
| Balanced Audio Visual Ltd | Information & communication | 2018 |
| Baldwins Lane Management Company Limited | Real estate | 2013 |
| Ballium Protective Security Services Ltd | Administrative & support | 2022 |
| Ballyvale Limited | Real estate | 2003 |
| Baltherranean Kitchen Ltd | Extraterritorial | 2025 |
| Bamboo Counselling and Psychotherapy Limited | Health & social care | 2018 |
| Banc Recruitment Ltd | Professional & scientific | 2020 |
| Banda DI Cantene Brew Co Limited | Hospitality | 2024 |
| Bang Your Drum Ltd | Education | 2023 |
| Bangs Estates Limited | Real estate | 2024 |
| Bankhead + Partners Limited | Professional & scientific | 2023 |
| Banking & Corporate Finance Consultants Limited | Financial services | 2000 |
| Bankside Partners Ltd | Professional & scientific | 2018 |
| Barber Associates Ltd | Professional & scientific | 2021 |
| Barber Wells Ltd | Other services | 2025 |
| Barca Consulting Ltd | Professional & scientific | 2025 |
| Barclay Merritt Limited | Real estate | 2020 |
| Bardens Estates Limited | Real estate | 2016 |
| Bargrove Mews Management Company Limited | Households | 2008 |
| Barisalcocktail Ltd | Hospitality | 2020 |
| Barkerdesign Interiors Ltd | Professional & scientific | 2021 |
| Barons Consultancy Ltd | Professional & scientific | 2021 |
| Barrack Manor Farm Limited | Administrative & support | 2019 |
| Barrington-Mayne Construction Ltd | Construction | 2019 |
| Bart Limited | Health & social care | 2009 |
| Bartlett Enterprises Limited | Wholesale & retail | 2024 |
| Bartoli Consultants Ltd | Professional & scientific | 2022 |
| Bartoli Lefevre Property Management Ltd | Real estate | 2022 |
| Barwell Court Estate LLP | | 2016 |
| Baseline Beat Limited | Education | 2014 |
| Basil Catering Services Limited | Hospitality | 2016 |
| Basil Wholefoods Limited | Wholesale & retail | 2017 |
| Bass Ecology Limited | Professional & scientific | 2024 |
| Bass Productions Limited | Information & communication | 2023 |
| Bass Property Management Ltd | Real estate | 2017 |
| Bastone & Ellis Automotive Ltd | Wholesale & retail | 2020 |
| Batch Tea Company Ltd | Wholesale & retail | 2018 |
| Batcheller Monkhouse Trustees Limited | Professional & scientific | 2025 |
| Batsirai Limited Company Limited | Health & social care | 2014 |
| Bauk Investments LLP | | 2025 |
| Bautista Beauty and Aesthetics Ltd | Other services | 2024 |
| BAW Consulting Ltd | Professional & scientific | 2015 |
| Baxterley House Management Limited | Households | 1996 |
| Bay Grape Consulting Limited | Professional & scientific | 2025 |
| Baycliffe Limited | Agriculture & fishing | 1995 |
| Baydar Ltd | Hospitality | 2011 |
| Bayhall Ltd | Professional & scientific | 2012 |
| Bayham Abbey Residents Association Limited | Other services | 1977 |
| Bayham Estates Limited | Real estate | 1995 |
| Bayham Holdings Group Limited | Information & communication | 2025 |
| Bayham Management Services Limited | Real estate | 2014 |
| Bayham Properties Limited | Real estate | 1995 |
| Bayham Property Holdings Limited | Real estate | 1996 |
| Bayley Limited | Wholesale & retail | 2021 |
| Baylis Associates UK Ltd | Other services | 2025 |
| BBA Remanufacturing Ltd | Other services | 2020 |
| BBH Construction Ltd | Construction | 2022 |
| BBH Developments Limited | Construction | 2024 |
| Bbni Limited | Financial services | 2018 |
| BC Electrical Solutions Ltd | Construction | 2017 |
| BDA Consulting Limited | Information & communication | 2017 |
| BDI Employee Holdings Ltd | Financial services | 2023 |
| BDK Financial Management Limited | Professional & scientific | 2012 |
| BDS Creative Limited | Arts & recreation | 2013 |
| Beach House Hove Limited | Hospitality | 2013 |
| Beacon Data Decision Intelligence Ltd | Information & communication | 2026 |
| Beacon Digital Health Ltd | Professional & scientific | 2026 |
| Beacon Park Ltd | Financial services | 2011 |
| Beam Law Legal Services Ltd | Professional & scientific | 2023 |
| Beam Law Ltd | Professional & scientific | 2011 |
| Bean & Co Ltd | Administrative & support | 2014 |
| Bean Consulting (UK) LLP | | 2012 |
| Bean Smitten Limited | Manufacturing | 2015 |
| Bear Isle Construction Ltd | Administrative & support | 2018 |