| Bargain Beer Ltd | Wholesale & retail | 2020 |
| Bari Digital Sports Ltd | Wholesale & retail | 2026 |
| Barker Tatham Investment Consultants Ltd | Professional & scientific | 2011 |
| Barkrobert Limited | Households | 1990 |
| Barkwood Close Management Limited | Households | 1989 |
| Barley Court Management Limited | Households | 1978 |
| Barn Field Place Management Limited | Households | 2007 |
| Barn International Limited | Construction | 2017 |
| Barnes Gate Management Company Limited | Households | 1998 |
| Barnes Information Technology Consultants Ltd | Information & communication | 2010 |
| Barnet ENG Ltd | Wholesale & retail | 2023 |
| Barnett Associates Limited | | 1979 |
| Barnettogm Limited | Hospitality | 2025 |
| Barnfield Shore Limited | Professional & scientific | 2000 |
| Barnoq Care Ltd | Administrative & support | 2025 |
| Barnoq Immigration Solutions Limited | Professional & scientific | 2024 |
| Barnsbury Grove Management Company Limited | Households | 2001 |
| Barnsbury Media Limited | Professional & scientific | 2024 |
| Barnwood Close Limited | Households | 1988 |
| Barnwood Place (Smarden) Management Company Limited | Households | 2022 |
| Barone 147 Ltd | Hospitality | 2022 |
| Barons Court Luton Limited | Households | 1991 |
| Barony Clothing UK Ltd | Manufacturing | 2025 |
| Barrett Boutique Ltd | Wholesale & retail | 2024 |
| Barrie Knitwear Limited | Manufacturing | 1994 |
| Barrons Court (Burton) Management Company Limited | Households | 2005 |
| Barros Global Trading Limited | Other services | 2020 |
| Barrow Brook Grange Management Company Limited | Households | 2011 |
| Barrowfields Close Residents Association Limited | Households | 2012 |
| Barry Alexander Estates Limited | Real estate | 2025 |
| Barry Deals Limited | Wholesale & retail | 2025 |
| Barry Taylor Tutoring Ltd | Education | 2020 |
| Barrys Derby Limited | Hospitality | 2026 |
| Bartek Trans Ltd | Transport & logistics | 2023 |
| Bartix Building Ltd | Construction | 2024 |
| Bartlett & Morrison Limited | Construction | 2003 |
| Bartley Wood Management Services Limited | Construction | 1987 |
| Bartley Wood Management Services NO.2 Limited | Professional & scientific | 1986 |
| Barton Court (Bristol) RTM Company Ltd | Households | 2023 |
| Barton Heath Management Company Limited | Households | 2015 |
| Barton Hill Pizza & Curry House Limited | Hospitality | 2025 |
| Barton London Consulting Limited | Professional & scientific | 2005 |
| Barton Mansions Limited | Households | 1971 |
| Barton Torquay Ltd | Wholesale & retail | 2025 |
| Bartons Mead Group Ltd | Financial services | 2022 |
| Barttech Engineering Ltd | Construction | 2026 |
| Baruta Ltd | Education | 2022 |
| Barzinji & Co Ltd | Professional & scientific | 2011 |
| Barzinji Investments Ltd | Real estate | 2026 |
| Basdol Consultancy Limited | Administrative & support | 2016 |
| Bash of London Tour and Travel Limited | Transport & logistics | 2023 |
| Basher 1 Limited | Households | 2001 |
| Basher 2 Limited | Households | 2001 |
| Bashir Mordor Consulting Limited | Information & communication | 2014 |
| Basic Management Limited | Professional & scientific | 2012 |
| Basic Prime Limited | Financial services | 2023 |
| Basildon Close (Sutton) Management Company Limited | Households | 2001 |
| Baskerville Residents Management Company Ltd | Households | 2022 |
| Bassi Convenience Stores Limited | Wholesale & retail | 2020 |
| Bassi Supermarket Limited | Wholesale & retail | 2022 |
| Basta London Limited | Hospitality | 2022 |
| Basta UK Limited | Health & social care | 2014 |
| Bateman & Knight Limited | Health & social care | 2019 |
| Bath Press Limited | Manufacturing | 1943 |
| Bath Riverside Albert Crescent Management Company Limited | Households | 2014 |
| Bath Riverside Corinthian Management Limited | Households | 2014 |
| Bath Riverside Estate Management Company Limited | Households | 2011 |
| Bath Riverside Leopold Management Company Limited | Households | 2015 |
| Bath Riverside Liberty Management Company Limited | Households | 2011 |
| Bath Riverside Royal View Management Company Limited | Real estate | 2017 |
| Bath Studio Limited | Other services | 2022 |
| Bath Supermarket Limited | Wholesale & retail | 2002 |
| Bathweston Residential Management Company Limited | Households | 2019 |
| Batista's Property Management Ltd | Real estate | 2019 |
| Batman Jardinagem Limited | Arts & recreation | 2025 |
| Batra Newsbox Limited | Wholesale & retail | 2010 |
| Battersea Triangle House Residents Company Limited | Households | 1986 |
| Battle Coffee Co. Ltd | Wholesale & retail | 2022 |
| Battle CRY Audio Limited | Other services | 2011 |
| Baxter Healthcare Pension Plan Trustees Limited | Financial services | 1960 |
| Baxter House (SE23) Management Company Limited | Households | 1996 |
| Baxters Quarter Management Company Limited | Households | 2007 |
| Bay Court (Freehold) Management Company Limited | Households | 2009 |
| Bay Court Residents Company Limited | Households | 1968 |
| Bay Green (Clevedon) Management Company Limited | Households | 2017 |
| Bay Ridges Consultants Ltd | Professional & scientific | 2021 |
| Bayat Group Limited | Professional & scientific | 2025 |
| Bayinet Ltd | Wholesale & retail | 2019 |
| Bayley Bakes and Party Services Limited | Manufacturing | 2012 |
| Baymead Apartments Limited | Households | 2013 |
| Baytree 4 Limited | Construction | 2020 |
| Baze Law & Rose Ltd | Real estate | 2026 |
| Bazi Cars Ltd | Wholesale & retail | 2024 |
| BB Holdco Limited | Financial services | 2024 |
| BB Wholesale Bakery Ltd | Wholesale & retail | 2024 |
| BBM Mgmt Ltd | Professional & scientific | 2024 |
| BC Dental Limited | Health & social care | 2013 |
| BC Livin Ltd | Real estate | 2025 |
| BC Vehicle Repairs Ltd | Wholesale & retail | 2019 |
| BC Warehouses Limited | Real estate | 2012 |