| Boghy&Lina Limited | Transport & logistics | 2016 |
| Boldfuseon Ltd | Information & communication | 2025 |
| Boldhelp Limited | Professional & scientific | 1999 |
| Boldnest Properties Ltd | Real estate | 2025 |
| Bolka Transport Ltd | Transport & logistics | 2018 |
| Bolt Automotive Ltd | Wholesale & retail | 2023 |
| Bombay Wraps Limited | Hospitality | 2026 |
| Boncold Limited | Manufacturing | 2007 |
| Bonds Beauty Salon Limited | Other services | 2009 |
| Bones 227 Ltd | Administrative & support | 2017 |
| Bonham Lilley Properties Limited | Real estate | 2006 |
| Book a Date Ltd | Information & communication | 2017 |
| Booker Cash & Carry Limited | Extraterritorial | 2005 |
| Booker Direct Limited | Wholesale & retail | 2000 |
| Booker Group Limited | Wholesale & retail | 2004 |
| Booker Limited | Wholesale & retail | 1924 |
| Booker Pension Trustees Limited | Administrative & support | 1956 |
| Booker Retail Limited | Wholesale & retail | 1927 |
| Booker Retail Partners (GB) Limited | Wholesale & retail | 2007 |
| Booker Unapproved Scheme Trustees Ltd | Administrative & support | 1997 |
| Booker Wholesale Holdings Limited | Professional & scientific | 2004 |
| Boosttech Ltd | Wholesale & retail | 2025 |
| Boot Island Limited | Wholesale & retail | 2025 |
| Bordas Brothers Limited | Hospitality | 2025 |
| Bors Trading Ltd | Wholesale & retail | 2020 |
| Bosco Shipping Ltd | Transport & logistics | 2022 |
| Boss Isaac Ltd | Construction | 2025 |
| Bossy Books Ltd | Professional & scientific | 2025 |
| Boston Central Apartments RTM Company Limited | Households | 2019 |
| Boston Central Management Company Limited | Real estate | 2006 |
| BOT Power AI Ltd | Information & communication | 2023 |
| Botra Cams Ltd | Manufacturing | 2023 |
| Bouldersons Limited | Professional & scientific | 2024 |
| Bouvo Ltd | Wholesale & retail | 2025 |
| Bowden Transportation Services Limited | Transport & logistics | 1991 |
| Boyinas Holdings Ltd | Financial services | 2023 |
| Bozeat Industrial Limited | Manufacturing | 1975 |
| BPA Associates Limited | Professional & scientific | 2017 |
| BPA Developments Ltd | Real estate | 2018 |
| BPA Immigration Lawyers Ltd | Professional & scientific | 2022 |
| BPD Underground Ltd | Construction | 2018 |
| Bradoks Limited | Transport & logistics | 2011 |
| Braille Battery UK Limited | Wholesale & retail | 2016 |
| Branded Vintage Clothing Limited | Wholesale & retail | 2024 |
| Brandpulse Media Limited | Professional & scientific | 2025 |
| Braxdan Roofing Limited | Construction | 2026 |
| BRC Import Export Ltd | Wholesale & retail | 2026 |
| BRE Holdings Ltd | Financial services | 2023 |
| BRE Medical Ltd | Other services | 2023 |
| Breakout Autos Ltd | Wholesale & retail | 2019 |
| Breaks-Away Respite Services C.I.C. | Health & social care | 2016 |
| Breaktime Cafe Ltd | Hospitality | 2020 |
| Bream Material Management Ltd | Construction | 2010 |
| Brett Ansell Limited | Administrative & support | 2022 |
| Brewbabu UK Limited | Hospitality | 2017 |
| Brey Engineering Ltd | Manufacturing | 2026 |
| Brian Cole Associates Limited | Construction | 1988 |
| Brickham Ltd | Real estate | 2004 |
| Brickpro Construction Ltd | Construction | 2026 |
| Bridge Engineering UK Limited | Wholesale & retail | 2003 |
| Bridlebrook Holdings Ltd | Real estate | 2017 |
| Brifak Healthcare Limited | Health & social care | 2022 |
| Bright Copper Kettles C.I.C. | Wholesale & retail | 2016 |
| Bright Smile LAB Ltd | Health & social care | 2024 |
| Brightoaks Childcare Ltd | Health & social care | 2019 |
| Brightwater Care & Support Ltd | Health & social care | 2020 |
| Brightwater Solutions Ltd | Professional & scientific | 2015 |
| Brikora Homes Ltd | Construction | 2026 |
| Briktec Limited | Construction | 2005 |
| Briktec Scaffolding Services Limited | Construction | 2017 |
| Bring the Noise Pyrotechnics Ltd | Extraterritorial | 2022 |
| Briteel Support Ltd | Transport & logistics | 2024 |
| British Drag Racing Hall of Fame Limited | Arts & recreation | 2016 |
| Brittons Plant Nurseries Limited | Agriculture & fishing | 2003 |
| Britwood Ltd | Wholesale & retail | 2019 |
| Broad Green Associates Ltd | Professional & scientific | 2009 |
| Broad Green Strategies LLP | | 2024 |
| Broad Walk by Natalie Smith Ltd | Wholesale & retail | 2022 |
| Broadwing Felixstowe (Leasehold) Limited | Real estate | 2020 |
| Brodwell Properties Limited | Real estate | 2025 |
| Bromborough Estate Company,Limited(The) | Agriculture & fishing | 1905 |
| Bromborough Estates Holding Co Limited | Financial services | 2019 |
| Bromham Electrical Ltd | Construction | 2021 |
| Bromsall Properties Ltd | Real estate | 2025 |
| Bromsgill Reeves LLP | | 2013 |
| Brook Farm Investments Ltd | Construction | 2023 |
| Brooklands Aviation Limited | Extraterritorial | 1973 |
| Brooklands Machining & Fabrications Limited | Extraterritorial | 1928 |
| Brookstone Property Ltd | Real estate | 2025 |
| Brookwell Design & Build Ltd | Construction | 2023 |
| Brookwell Lettings Limited | Real estate | 2019 |
| Brownage Mode Ltd | Information & communication | 2020 |
| BRS Motors Ltd | Wholesale & retail | 2020 |
| Brundall Bay Marina Limited | Real estate | 2002 |
| Bryan's Motors Ltd | Wholesale & retail | 2012 |
| BSR - BEN Sharpe Racing Ltd | Wholesale & retail | 2023 |
| BTL Health, Living & Working Solutions Limited | Real estate | 2020 |
| BTN Trans Ltd | Transport & logistics | 2025 |
| BTP Performance Ltd | Professional & scientific | 2023 |
| Bubbles and Paws Parlour Ltd | Other services | 2025 |