| Benchmark Waste Limited | Water & waste | 2015 |
| Bengal Bees Media Ltd | Information & communication | 2023 |
| Benjamin Barber Limited | Professional & scientific | 2012 |
| Benjamin Thomas Interiors Limited | Wholesale & retail | 2026 |
| Benjamins Walk Management Company Limited | Households | 2008 |
| Benons Ltd | Hospitality | 2017 |
| Bentley's Coffee Shop Limited | Wholesale & retail | 2016 |
| Beritan Property Ltd | Real estate | 2024 |
| Bernie's Barbers Ltd | Other services | 2022 |
| Bernies Property Co Limited | Real estate | 2003 |
| Berry IT Services Ltd | Information & communication | 2018 |
| Berry&Blossoms Ltd | Wholesale & retail | 2017 |
| Bert Solutions Ltd | Wholesale & retail | 2018 |
| Bespoke Home Interiors Ltd | Manufacturing | 2021 |
| Bespoke Recycling Ltd | Water & waste | 2021 |
| Bespoke Recycling Solutions Ltd | Water & waste | 2018 |
| Best Barber Grimsby Ltd | Other services | 2025 |
| Best Barber N32 Ltd | Other services | 2025 |
| Best Futures Community Interest Company | Education | 2014 |
| Best of London Limited | Wholesale & retail | 2017 |
| Bestall, Betmead & Buck Limited | Information & communication | 2025 |
| Bethesda Limited | Health & social care | 2010 |
| Betitrans Ltd | Transport & logistics | 2016 |
| Betner Limited | Transport & logistics | 2016 |
| Bettank Services Limited | Transport & logistics | 2012 |
| Better Days Caribbean Cuisine Ltd | Hospitality | 2025 |
| Better Solutions Sound and Lighting Limited | Administrative & support | 2017 |
| Betty Mckenzie Limited | Wholesale & retail | 2012 |
| BEX Beers Ltd | Hospitality | 2024 |
| BEX Productions Ltd | Information & communication | 2021 |
| Beyond Instinct Ltd | Other services | 2019 |
| Beyond News & Booze Ltd | Wholesale & retail | 2023 |
| Beyond the Shore CIC | Education | 2026 |
| BG Solicitors LLP | | 2011 |
| BGC Solutions Ltd | Information & communication | 2015 |
| Bgtrans 73 Ltd | Transport & logistics | 2017 |
| Bhullar Group Holdings Ltd | Financial services | 2022 |
| Bidding to Build Limited | Construction | 2025 |
| Biegun Agricultural Limited | Agriculture & fishing | 2012 |
| Bielby & Wright Property Management Ltd | Real estate | 2020 |
| Bierlow Ltd | Water & waste | 2016 |
| Big Fish (Seafoods) Limited | Wholesale & retail | 2000 |
| Big Mood Studio Ltd | Information & communication | 2025 |
| Big Red Living the Dream Ltd | Wholesale & retail | 2015 |
| Big Skull Media Ltd | Information & communication | 2016 |
| Bill Blackmore Ltd | Wholesale & retail | 2016 |
| Bilton Lettings Limited | Real estate | 2022 |
| Bilton's Estate Agency Limited | Real estate | 2020 |
| Bilton's Removals Limited | Transport & logistics | 2025 |
| Binatone Telecom PLC | Wholesale & retail | 1990 |
| Binckley Limited | Real estate | 1993 |
| Bing Bing Holdings Ltd | Professional & scientific | 2018 |
| Bingham & Co Limited | Other services | 2017 |
| Binik Ltd | Transport & logistics | 2018 |
| Birch View Joinery Ltd | Construction | 2026 |
| Birchwood Building & Joinery Contractors Limited | Construction | 2003 |
| Bird & Goodwin Limited | Construction | 2002 |
| Bird's EYE Sports & Social Club Limited | Hospitality | 2005 |
| Birdhouse Projects Ltd | Arts & recreation | 2011 |
| Birdkids Ltd | Wholesale & retail | 2020 |
| Birmingham Motor Parts Store Ltd | Wholesale & retail | 2011 |
| Bishops Leisure Ltd | Wholesale & retail | 2025 |
| Bitter Fairy Limited | Wholesale & retail | 2008 |
| Biysa Limited | Financial services | 2026 |
| BJ Hickman Limited | Construction | 2003 |
| BJP Hazardous Area Services Ltd | Construction | 2017 |
| BJW Installations Limited | Construction | 2014 |
| BK Convenience Store Private Limited | Wholesale & retail | 2025 |
| BKN Media Ltd | Information & communication | 2023 |
| BKR Transport Ltd | Transport & logistics | 2017 |
| Blac Bocs Limited | Construction | 2001 |
| Black and White Trans Ltd | Wholesale & retail | 2025 |
| Black Country Barbers Ltd | Other services | 2019 |
| Black Holt Wood Ltd | Manufacturing | 2022 |
| Black Sun Systems Ltd | Information & communication | 2024 |
| Black Swan Dance Studios Ltd | Arts & recreation | 2020 |
| Blackburn Wigglesworth and Associates Limited | Professional & scientific | 1998 |
| Blackdiamond Contracting Ltd | Other services | 2013 |
| Blackgate Logistics Limited | Transport & logistics | 2000 |
| Blackinkmotors Ltd | Wholesale & retail | 2021 |
| Blackrow Corporation Limited | Professional & scientific | 2009 |
| Blackrow Engineering Co. Limited | Manufacturing | 1980 |
| Blackrow Wind Limited | Professional & scientific | 2023 |
| Blackstone Energy Consulting Limited | Professional & scientific | 2026 |
| Blackwater Agri Services Limited | Water & waste | 2018 |
| Blades (Lincs) Ltd | Construction | 2019 |
| Blake Coaching and Care Services Limited | Real estate | 2019 |
| Blended Limited | Other services | 2008 |
| Blessed Shine Events Ltd | Hospitality | 2025 |
| Blessed UP Limited | Manufacturing | 2016 |
| Blink Pictures Ltd | Information & communication | 2024 |
| Blinksy Ltd | Wholesale & retail | 2025 |
| BLN Trans Limited | Transport & logistics | 2025 |
| Blockchain Engineering Ltd | Professional & scientific | 2025 |
| Bloods UK Limited | Professional & scientific | 2022 |
| Blossom Hill Equestrian Ltd | Agriculture & fishing | 2021 |
| Blossom Hill Equestrian Training and Sales Ltd | Agriculture & fishing | 2023 |
| Blossom's Trendy Clothing Limited | Wholesale & retail | 2007 |
| Blow Abbott Limited | Professional & scientific | 2021 |
| Blox Holdings Limited | Financial services | 2019 |