| Beyond Supply Chain Results Ltd | Professional & scientific | 2012 |
| Bhandl Limited | Financial services | 2020 |
| Bharat Venture Limited | Wholesale & retail | 2021 |
| Bhavi Measuria Ltd | Health & social care | 2026 |
| BHK365 Trading Ltd | Wholesale & retail | 2025 |
| Biamworks Ltd | Manufacturing | 2006 |
| Bibielle UK Limited | Wholesale & retail | 1999 |
| Biedronka Mini Market Limited | Wholesale & retail | 2026 |
| Bifl Ltd | Hospitality | 2026 |
| Big BOY Films Ltd | Administrative & support | 2023 |
| Big Juicy Burgers Loughborough Ltd | Hospitality | 2025 |
| Big ME UP Media Limited | Professional & scientific | 2012 |
| Big Pistachio Ltd | Real estate | 2016 |
| Big Show Construction Ltd | Construction | 2024 |
| Bigebasket Limited | Wholesale & retail | 2025 |
| Biharis Beyond Boundaries Community Interest Company | Professional & scientific | 2024 |
| Bill Cooling Butchers Limited | Wholesale & retail | 2012 |
| Billfreehomes (Leasing) Ltd | Extraterritorial | 2001 |
| Billionaire Desserts Ltd | Hospitality | 2018 |
| BIM Logistics Ltd | Transport & logistics | 2017 |
| Bimpus Ventures Ltd | Real estate | 2020 |
| Binder Energy Assessors Ltd | Professional & scientific | 2023 |
| Binghams SS Limited | Real estate | 2015 |
| Binotto (UK) Limited | Wholesale & retail | 1999 |
| Biocmc Consulting Ltd | Professional & scientific | 2021 |
| Biohackme Ltd | Health & social care | 2026 |
| Biospag Limited | Manufacturing | 2012 |
| Biowellness Care Limited | Health & social care | 2025 |
| Birchway Developments Ltd | Real estate | 2000 |
| Bird and Co London Ltd | Professional & scientific | 2022 |
| Bird Brain Technology Ltd | Information & communication | 2025 |
| Bird Nest Property Services Ltd | Real estate | 2019 |
| Bird Wilford and Sale Limited | Professional & scientific | 2020 |
| Birdhouse Design Limited | Information & communication | 2006 |
| Biroman Limited | Extraterritorial | 1993 |
| Bison Group Holdings Ltd | Financial services | 2025 |
| Bison Handling Services Ltd | Professional & scientific | 1962 |
| Bite Frenzy Ltd | Construction | 2024 |
| Bits and Bobs Distribution Ltd | Wholesale & retail | 2018 |
| Bivt Healthcare Solutions Ltd | Health & social care | 2024 |
| Biztekc Consulting Ltd | Professional & scientific | 2024 |
| BK Management and Consulting Ltd | Professional & scientific | 2023 |
| BK Plumbing & Heating Services Ltd | Construction | 2021 |
| BKL Auto Parts Ltd | Wholesale & retail | 2024 |
| BKS Consulting Loughborough Limited | Professional & scientific | 2012 |
| BL Motorsport Fabrications Ltd | Manufacturing | 2023 |
| Blaby Business Centre Limited | Real estate | 2007 |
| Blaby Developments Limited | Construction | 2022 |
| Blaby Developments Management Company Ltd | Households | 2023 |
| Black Matter Ltd | Hospitality | 2025 |
| Black Mountain Leics Ltd | Hospitality | 2025 |
| Black OX Marketing Ltd | Wholesale & retail | 2026 |
| Black Piranha Limited | Professional & scientific | 2019 |
| Black Stripe Property Ltd | Real estate | 2017 |
| Black Tulip Port ST. George Bahamas Limited | Extraterritorial | 2022 |
| Blackbelt Performance Consultancy Limited | Education | 2026 |
| Blackink Co-Operation Limited | Professional & scientific | 2024 |
| Blades Traditional Limited | Construction | 2022 |
| Blanco Wealth Management Limited | Financial services | 2017 |
| Blankney House Limited | Construction | 2019 |
| Blast Technology Limited | Construction | 1989 |
| Blesh Holdings Ltd | Financial services | 2022 |
| Bliss Box Store Ltd | Wholesale & retail | 2025 |
| Blobfish Media Ltd | Information & communication | 2018 |
| Blockbuster Development Limited | Extraterritorial | 2021 |
| Bloom Cloud Limited | Information & communication | 2014 |
| Blossom Tree Day Nursery @ Terracotta Court Limited | Health & social care | 2024 |
| Blossomco Limited | Extraterritorial | 2013 |
| Bloxham Group Ltd | Wholesale & retail | 2025 |
| Bloxham, Brooks & Bailey Ltd | Financial services | 2018 |
| Blue Boar Leicester Ltd | Hospitality | 2021 |
| Blue Diamond Wellbeing Limited | Health & social care | 2018 |
| Blue FOX Construction Ltd | Construction | 2013 |
| Blue FOX Events (Leicester) Ltd | Arts & recreation | 2019 |
| Blue FOX PUB Company Ltd | Hospitality | 2023 |
| Blue Horse Letting Ltd | Real estate | 2014 |
| Blue House Property Limited | Real estate | 2002 |
| Blue Lady Estates Ltd | Hospitality | 2025 |
| Bluebell Catering Ltd | Hospitality | 2022 |
| Blueberry Dressage Limited | Arts & recreation | 2013 |
| Blueline Leisure Limited | Arts & recreation | 2011 |
| Blueshire Limited | Wholesale & retail | 2004 |
| Bluestone Marketing Limited | Manufacturing | 2004 |
| Blunt Soar Limited | Manufacturing | 2018 |
| Blythin and Brown (Insurance Brokers) Limited | Administrative & support | 1972 |
| BLÚ Plumbing Solutions Limited | Construction | 2024 |
| BMJ Commercial Ltd | Real estate | 2019 |
| BMJ Developments Ltd | Real estate | 2019 |
| BMJ Management Ltd | Real estate | 2025 |
| BML Trading Ltd | Manufacturing | 2025 |
| Bnlcatering Ltd | Hospitality | 2024 |
| BNR Block Management Limited | Real estate | 2009 |
| BNR Lettings and Sales Limited | Real estate | 2018 |
| BNR Property Services Ltd | Construction | 2009 |
| BNR Student Lettings Limited | Real estate | 2018 |
| Boal U.K. Limited | Manufacturing | 1987 |
| Boardman Coaching Ltd | Education | 2024 |
| Boba Bubble Ltd | Wholesale & retail | 2022 |
| Bobby's Foods (South East) Limited | Hospitality | 1991 |
| Bobby's Foods East Anglia Limited | Hospitality | 1992 |