| Boutinot Canada Limited | Wholesale & retail | 2018 |
| Boutinot International Limited | Wholesale & retail | 2019 |
| Boutinot Limited | Wholesale & retail | 1980 |
| Boutinot USA Limited | Wholesale & retail | 2018 |
| Boutinot Wines Limited | Wholesale & retail | 2011 |
| Bowe Consultants Ltd | Information & communication | 2019 |
| Bowness Pharmacy Limited | Wholesale & retail | 2008 |
| Boys' and Girls' Welfare Society Limited | Extraterritorial | 2005 |
| Bpjm Projects Limited | Professional & scientific | 2023 |
| BQ Property Ltd | Real estate | 2022 |
| Brabant Limited | Wholesale & retail | 1980 |
| Brabyns Lawn Tennis Club Limited | Arts & recreation | 1926 |
| Bracken MIDCO1 PLC | Financial services | 2016 |
| Bracken MIDCO2 Limited | Financial services | 2016 |
| Bracken Topco Limited | Financial services | 2016 |
| Brackley Court (Longley Lane) Limited | Households | 2013 |
| Bradgate Close RTM Company Limited | Hospitality | 2013 |
| Bradley Assets Ltd | Financial services | 2024 |
| Braintree Property Management Ltd | Households | 2015 |
| Brampton Home Surveys Limited | Professional & scientific | 2018 |
| Brand Sprout Ltd | Wholesale & retail | 2024 |
| Brandana Properties Ltd | Real estate | 2017 |
| Brandwin Digital Ltd | Professional & scientific | 2021 |
| Braniel Property Management Ltd | Real estate | 2022 |
| Bravura Interiors Ltd | Manufacturing | 2023 |
| Brazil Street Ltd | Professional & scientific | 2014 |
| Bread and Butties Limited | Hospitality | 2015 |
| Breaducate Limited | Wholesale & retail | 2019 |
| Bredbury Park Limited | Real estate | 2024 |
| Brendons Care Ltd | Wholesale & retail | 2022 |
| Brewch Manchester Ltd | Hospitality | 2023 |
| Brewger Coffee Ltd | Wholesale & retail | 2026 |
| Brian C. Corcoran Limited | Professional & scientific | 1991 |
| Brian Pennington Ltd | Information & communication | 2024 |
| Bridge 2016 Limited | Real estate | 2016 |
| Bridging Finance Limited | Financial services | 1996 |
| Bridging Range Finance 23 Limited | Financial services | 2023 |
| Bridging Range Holding Limited | Financial services | 2023 |
| Bright Beginnings Day Nurseries Limited | Health & social care | 2001 |
| Bright Property Sourcing Ltd | Real estate | 2022 |
| Brightonrock Communications Limited | Information & communication | 2001 |
| Brightstarbi.Com Limited | Information & communication | 2018 |
| British Association of Paediatricians in Audiology | Professional & scientific | 2010 |
| British Society of Aesthetics(The) | Education | 1966 |
| Brixvoir Limited | Construction | 2026 |
| Brkah Ltd | Real estate | 2025 |
| Broad Ford Investments Limited | Other services | 2019 |
| Broad Street Real Estate Group Limited | Financial services | 2016 |
| Broburn Partners Limited | Professional & scientific | 2023 |
| Brodega Ltd | Hospitality | 2024 |
| Bromley Estates Cheshire Ltd | Real estate | 2022 |
| Brookhead Estate Limited | Real estate | 1937 |
| Brookhill Estates Limited | Real estate | 2002 |
| Brooklands Crescent (East View) Limited | Households | 1979 |
| Brooks Capital Ltd | Information & communication | 2024 |
| Broome Management Co. Limited | Real estate | 2013 |
| Broomstairs Farm Ltd | Agriculture & fishing | 2021 |
| Brow Couture 1 Ltd | Other services | 2024 |
| Brownsville Road Management Company Limited | Real estate | 2016 |
| Brows and Aesthetics by LOU Limited | Other services | 2022 |
| Bruntwood Enterprises Limited | Real estate | 2022 |
| Bruntwood Properties Ltd | Households | 2021 |
| Bruntwood Services Limited | Construction | 2023 |
| Brush & Canva Ltd | Construction | 2025 |
| Brush & HUE UK Ltd | Construction | 2025 |
| Bsnajjar Ltd | Administrative & support | 2023 |
| Bspn Ltd | Information & communication | 2025 |
| Btequipment UK Ltd | Wholesale & retail | 2014 |
| Btpm Limited | Real estate | 2016 |
| Bu&V Ltd | Construction | 2024 |
| Buckley House Management Company Limited | Real estate | 2000 |
| Budding Prescribing Limited | Health & social care | 2025 |
| Budworth Sailing Section (Properties) Limited | Real estate | 1962 |
| Build People Ltd | Administrative & support | 2016 |
| Building Product Design Limited | Extraterritorial | 2000 |
| Building Psychological Capital Ltd | Professional & scientific | 2020 |
| Buildwick Ltd | Administrative & support | 2017 |
| Buile (ST Lawrence House) Limited | Real estate | 2014 |
| Built by NIC Limited | Education | 2026 |
| Bulkeley Commercial Limited | Professional & scientific | 1991 |
| Bullseye Rally Ltd | Professional & scientific | 2017 |
| Bumblebee Bakes Ltd | Manufacturing | 2022 |
| Burlington Court Flats (Altrincham) Limited | Households | 1977 |
| Burr Living Two LLP | | 2015 |
| Burrbaxter Print Ltd | Manufacturing | 2008 |
| Bury Drains Limited | Water & waste | 2016 |
| BUS & Commercial Services Ltd | Administrative & support | 2004 |
| Buse Beauty Limited | Other services | 2020 |
| Bush Property 1 Limited | Real estate | 2024 |
| Business Builders Club Limited | Professional & scientific | 2025 |
| Business in Mind Limited | Information & communication | 2014 |
| Business Rates Advisors Limited | Extraterritorial | 2020 |
| Busy BEE Cleaning Group Limited | Administrative & support | 2026 |
| Butek Limited | Real estate | 2006 |
| Butterfly Kisses Consulting UK Limited | Other services | 2025 |
| Butterfly Kisses Limited | Professional & scientific | 2018 |
| BWA Financial Ltd | Financial services | 2025 |
| BXC Developments Ltd | Construction | 2019 |
| Bylia Ltd | Manufacturing | 2018 |
| Byrne Byrne Limited | Real estate | 2017 |