| Beeware Pest and Enviromental Services Ltd | Other services | 2011 |
| Bell Mount Farming Ltd | Agriculture & fishing | 2014 |
| Bells of Lazonby (Holdings) Limited | Professional & scientific | 1990 |
| Bells of Lazonby Holdings 2020 Limited | Financial services | 2020 |
| Bells of Lazonby Limited | Manufacturing | 1951 |
| Berkeley House Bowscar Ltd | Real estate | 2025 |
| Besa Limited | Extraterritorial | 2015 |
| Besa Publications Limited | Information & communication | 1995 |
| Bgww Limited | Construction | 2022 |
| Bill Preston Limited | Real estate | 2015 |
| Billed Pro Ltd | Construction | 2023 |
| Birchwood Barn | Other services | 2024 |
| Birds Bistro Enterprises Limited | Agriculture & fishing | 2012 |
| Birds Free Range Eggs | Wholesale & retail | 2015 |
| Birkbeck Electrical Contracting Ltd | Construction | 2025 |
| Birkbeck Engineering Ltd | Professional & scientific | 2025 |
| Birtles & Co Cleaning Services Ltd | Manufacturing | 2026 |
| Black Cat Distillery Ltd | Manufacturing | 2022 |
| Black Robin Capital Limited | Financial services | 2024 |
| Black Swan Culgaith Ltd | Hospitality | 2019 |
| Blackwood Security. Limited | Administrative & support | 2024 |
| Blades Development Ltd | Construction | 2024 |
| Blair Farming Limited | Agriculture & fishing | 2018 |
| Blazers Fuels Limited | Manufacturing | 2013 |
| Blazers Group Limited | Manufacturing | 2022 |
| Blencarn Estate Limited | Professional & scientific | 2005 |
| Blind Beck Systems Limited | Information & communication | 1998 |
| Bliss Beauty & Wellness Ltd | Other services | 2026 |
| Blokk Studio Ltd | Professional & scientific | 2023 |
| BLU Bars Ltd | Hospitality | 2019 |
| Blue COG Cycling Limited | Administrative & support | 2010 |
| Blue DOT Music Studios Ltd | Information & communication | 2024 |
| Blue Moon Cafe Media Limited | Wholesale & retail | 2016 |
| Blue Sky Yonder Limited | Financial services | 2007 |
| Bluebird Inns Limited | Hospitality | 2020 |
| Bluejam Arts CIC | Arts & recreation | 2007 |
| Bluestar (North West) Limited | Administrative & support | 2009 |
| BOB Atkinson Transport Limited | Transport & logistics | 2005 |
| Bobbin Mill Hall Trust Limited(The) | Other services | 1982 |
| Bondtech Limited | Wholesale & retail | 2006 |
| Bookgodo Ltd | Information & communication | 2020 |
| Boonwood Restaurant Limited | Hospitality | 2015 |
| Border Water Technologies Ltd | Construction | 2004 |
| BOS International Ltd | Professional & scientific | 2016 |
| Bousfield Projects Limited | Construction | 2015 |
| Bowland Fold (Halton) Limited | Construction | 2021 |
| Bowland Fold (Halton) Management Company Limited | Households | 2022 |
| Bowscar Investments Ltd | Real estate | 1999 |
| BPA Electrical Services Ltd | Construction | 2015 |
| BPW Fire Safety Limited | Professional & scientific | 2016 |
| BR Medical Services Ltd | Health & social care | 2019 |
| Bracecastle Limited | Hospitality | 2021 |
| Brackenslack Shepherds Huts Limited | Hospitality | 2017 |
| Braffin Heights Management Company Ltd | Households | 2023 |
| Braithwaites Garage Limited | Wholesale & retail | 2006 |
| Branch OUT Education CIC | Education | 2017 |
| Brand Nuvu Limited | Real estate | 2017 |
| Brand Project Ltd | Professional & scientific | 2015 |
| Breed Clean Limited | Administrative & support | 2002 |
| Brewers Road Haulage Ltd | Transport & logistics | 2002 |
| Brewin Sports Limited | Arts & recreation | 2017 |
| Brick London (Events) Ltd | Administrative & support | 2019 |
| Bridgefield Property Management Company Limited | Extraterritorial | 2024 |
| Broad ING Management Company Limited | Real estate | 1997 |
| Broadmeadows Farm | Administrative & support | 2010 |
| Broadview Partners Limited | Extraterritorial | 2016 |
| Broadway (Barrow) Limited | Hospitality | 2013 |
| Brockholes Blacknoses Ltd | Agriculture & fishing | 2024 |
| Brockles Limited | Other services | 2003 |
| Brooks Siblings Ltd | Agriculture & fishing | 2025 |
| Broomdykes Farms Limited | Agriculture & fishing | 1970 |
| Brougham Hall CIC | Arts & recreation | 2024 |
| Brownelson Properties Ltd | Real estate | 2001 |
| Brunger's Buildings Ltd | Real estate | 2025 |
| Brunskill Management Limited | Other services | 1963 |
| Bryan Bolton Joinery Limited | Construction | 2014 |
| Bryan Groves Building Contractors Limited | Construction | 2002 |
| BUD Designs Limited | Manufacturing | 2023 |
| Building and Engineering Services Association Limited | Professional & scientific | 2011 |
| Building Engineering Services Competence Assessment Limited | Administrative & support | 1999 |
| Building Engineering Services Training Limited | Administrative & support | 1993 |
| Bulman's Bulk & Haulage Limited | Transport & logistics | 1982 |
| Bulmans (Penrith) Limited | Extraterritorial | 1985 |
| Burnbanks Management Co Ltd. | Households | 2005 |
| Burns Farm Ltd | Hospitality | 2023 |
| Burnthwaite Accommodation Limited | Hospitality | 2013 |
| Burrow & Rutter-Armstrong Engineering Ltd | Wholesale & retail | 2019 |
| Bury Smile Line Limited | Health & social care | 2015 |
| Bush Nook Ltd | Hospitality | 2024 |
| Bustan Investments Limited | Construction | 1986 |
| Button Enterprise Limited | Financial services | 2021 |
| Buzz Publishing Limited | Information & communication | 2021 |
| C & D Logistics South East Limited | Other services | 1999 |
| C & L Services (UK) Limited | Construction | 2004 |
| C & V Developments Ltd. | Construction | 2002 |
| C Hind Construction Limited | Construction | 2025 |
| C M Dent Limited | Health & social care | 2015 |
| C R Sisson Decorators Limited | Construction | 2002 |
| C Walker Services Limited | Construction | 2020 |
| C Wilson Plumbing & Heating Ltd | Construction | 2023 |