| Biodrive Ltd | Professional & scientific | 2014 |
| Biogenia Limited | Construction | 2016 |
| Biomine Limited | Information & communication | 2023 |
| Bionol Hair Limited | Health & social care | 2026 |
| Bioweld Materials Limited | Professional & scientific | 2026 |
| Birchland Properties Limited | Agriculture & fishing | 1963 |
| Birchwood BIO Ltd | Professional & scientific | 2022 |
| Birlirakis Ltd | Health & social care | 2019 |
| Birmingham Upper Gastrointestinal Surgery Limited | Health & social care | 2019 |
| Bishops Property Development Limited | Construction | 2014 |
| Bishopstrow House Ltd | Hospitality | 2021 |
| Bison Eco Limited | Agriculture & fishing | 2024 |
| Bison Limited | Administrative & support | 2009 |
| Bison Waste Solutions Limited | Water & waste | 2025 |
| Bistreya Limited | Wholesale & retail | 2024 |
| Bite Access Limited | Professional & scientific | 1993 |
| Bitmap Books Ltd | Information & communication | 2014 |
| Biznews Limited | Information & communication | 2016 |
| Bizval Ltd | Professional & scientific | 2023 |
| Bjhaccountancy Ltd | Professional & scientific | 2021 |
| BK Auto Groups Ltd | Wholesale & retail | 2023 |
| Bkms Bath Ltd | Hospitality | 2015 |
| Blaax Coffee Co Ltd | Hospitality | 2024 |
| Black Beck Consultancy (North West) Limited | Professional & scientific | 2014 |
| Black Combe Limited | Information & communication | 2016 |
| Black Panther Models Ltd | Administrative & support | 2023 |
| Blacklab Partners Limited | Professional & scientific | 2017 |
| Blackmore Events Company Ltd | Arts & recreation | 2024 |
| Blacksmiths Forge Management Company Limited | Households | 2002 |
| Bladud Spring Limited | Manufacturing | 2017 |
| Bladuds Head Limited | Hospitality | 2012 |
| Blagden Hospitality Ltd | Professional & scientific | 2023 |
| Blank View Ltd | Wholesale & retail | 2023 |
| Blast Ecoshield Limited | Professional & scientific | 2026 |
| Blaze Holdings Limited | Financial services | 2015 |
| Blaze Productions Limited | Manufacturing | 1998 |
| Blendground Property Management Limited | Real estate | 1987 |
| Blenheim Accountancy Partnership Limited | Professional & scientific | 2006 |
| Blenheim Building Contractors Limited | Construction | 2008 |
| Blenheim Tax and Accountancy Services Limited | Professional & scientific | 2006 |
| Blezard Property Limited | Real estate | 2020 |
| Blhe Limited | Administrative & support | 2022 |
| Bliss Yoga Limited | Extraterritorial | 2022 |
| Blitzboyz Limited | Information & communication | 2020 |
| Block G Limited | Information & communication | 2015 |
| Block Network Limited | Information & communication | 2022 |
| Blockchain Gang Ltd | Professional & scientific | 2022 |
| Bloingo Games Ltd | Information & communication | 2025 |
| Blok Building Design & Construction Limited | Construction | 2016 |
| Blok DEV SPV1 Limited | Construction | 2025 |
| Blok Developments Limited | Construction | 2025 |
| Blok Group Limited | Financial services | 2025 |
| Bloomfield Bookkeeping Ltd | Professional & scientific | 2012 |
| Bloomfield Botanicals Ltd | Extraterritorial | 2024 |
| Bloomfield Building Solutions Ltd | Wholesale & retail | 2022 |
| Bloomfield Crescent (Bath) Management Company Limited | Professional & scientific | 2015 |
| Bloomfield Financial Solutions Ltd | Professional & scientific | 2012 |
| Bloomfield Heritage Ltd | Real estate | 2025 |
| Bloomfields Sports Co.Limited | Arts & recreation | 1927 |
| Blossom and Wren Academy C.I.C. | Education | 2022 |
| Blossom Flavours Ltd | Wholesale & retail | 2025 |
| Blossombath Ltd | Hospitality | 2025 |
| Blowout SAX Limited | Wholesale & retail | 2001 |
| BLR Nail Ltd | Other services | 2025 |
| Blubolt Limited | Information & communication | 2006 |
| Blue & BAD Limited | Real estate | 2002 |
| Blue Acorn Solutions Limited | Professional & scientific | 2010 |
| Blue Badge Access Awards Limited | Extraterritorial | 2018 |
| Blue Birch Properties Ltd | Real estate | 2024 |
| Blue Cafe Coffee Ltd | Hospitality | 2022 |
| Blue Fuse Systems Limited | Information & communication | 2005 |
| Blue Lagoon Consultancy Limited | Real estate | 2006 |
| Blue Luna Properties Ltd | Real estate | 2025 |
| Blue Mango Accountants Ltd | Professional & scientific | 2025 |
| Blue Monkey Brain Ltd | Administrative & support | 2013 |
| Blue Peacock Properties Limited | Real estate | 2010 |
| Blue Scorpio Limited | Financial services | 2014 |
| Blue Sky Accounting Ltd | Professional & scientific | 2022 |
| Blue Sky Film & Media Limited | Other services | 2000 |
| Blue Sky Tennis Foundation CIC | Arts & recreation | 2022 |
| Blue Spa & Leisure Consultants Limited | Wholesale & retail | 2002 |
| Blue Spike Limited | Construction | 2014 |
| Blue Wembury Ltd | Extraterritorial | 2013 |
| Blue Wolf Digital Ltd | Administrative & support | 2022 |
| Bluebell French Interiors Ltd | Professional & scientific | 2025 |
| Blueberry Drive Ltd | Wholesale & retail | 2022 |
| Bluebird Airways Limited | Extraterritorial | 2011 |
| Bluebird Aviation Engineering Ltd | Manufacturing | 2023 |
| Bluebird Investments (Marshfield) Ltd | Real estate | 2020 |
| Bluebuoy IT Support Ltd | Information & communication | 2011 |
| Bluecap Importing Limited | Wholesale & retail | 2016 |
| Bluecass Ltd | Professional & scientific | 2011 |
| Bluedune Limited | Professional & scientific | 2013 |
| Bluefuse Investments Limited | Financial services | 2020 |
| Bluemesh Technologies Limited | Information & communication | 2025 |
| Bluemill Properties Limited | Construction | 2015 |
| Bluerock Ventures Ltd | Mining & quarrying | 2016 |
| Bluesky Tennis Limited | Arts & recreation | 2019 |
| Blueskytec Ltd | Professional & scientific | 2012 |
| Bluespark MC Limited | Professional & scientific | 2006 |