| Bench Studio Ltd | Manufacturing | 2020 |
| Bendidia Limited | Real estate | 2024 |
| Benfield Marketing Limited | Public administration | 2024 |
| Benmia Limited | Information & communication | 2022 |
| Benouaer Technology Consulting Ltd | Information & communication | 2017 |
| Benridge Park Management Limited | Real estate | 2002 |
| Benson and Benson LLP | | 2018 |
| Bentech Medical Ltd | Wholesale & retail | 2022 |
| Bere Regis Properties Limited | Real estate | 2011 |
| Berrington Management Limited | Households | 2006 |
| Berties Country Ltd | Wholesale & retail | 2011 |
| Bespoke Bath and Steam Room Installations Ltd | Construction | 2024 |
| Bespoke Commercial Concepts Ltd | Professional & scientific | 2020 |
| Bespoke Projects International Ltd | Manufacturing | 2024 |
| Bespoke Tutoring by Kimberley Ltd | Education | 2024 |
| Best FED Babies Corfe Mullen CIC | Education | 2025 |
| Best One Team Ltd | Wholesale & retail | 2018 |
| Besttravelmoney Ltd | Information & communication | 2022 |
| Beth Quarrie Contracting BQC Ltd | Other services | 2018 |
| Better Outcomes Limited | Professional & scientific | 2019 |
| Beyond Benchmark Consultancy Ltd | Administrative & support | 2023 |
| Beyond Binary Ltd | Information & communication | 2018 |
| BFG Rattan Furniture Ltd | Wholesale & retail | 2017 |
| BFS Fire Solutions Ltd | Public administration | 2026 |
| BH Aquagas Ltd | Construction | 2025 |
| BH Construction & Maintenance Ltd | Construction | 2020 |
| BH Glazing Supplies Ltd | Construction | 2022 |
| BH Maison Limited | Real estate | 2017 |
| BH Parking Ltd | Hospitality | 2019 |
| BH Remedial & Renovation Services Limited | Construction | 2008 |
| BH14 Travel Limited | Administrative & support | 2024 |
| BH21 Property Ltd | Real estate | 2025 |
| Bhatia Consultants Limited | Information & communication | 2026 |
| Bhplumbtech Ltd | Construction | 2024 |
| Bickerley Gardens Freehold Limited | Households | 2003 |
| Bickerley Gardens Management Limited | Households | 1994 |
| BID Performance Ltd | Professional & scientific | 2022 |
| Bidouks Ltd | Information & communication | 2023 |
| Big Apple (Superbowl) Limited | Arts & recreation | 2008 |
| Big Apple Entertainments (Holdings) Limited | Arts & recreation | 2017 |
| Big Apple Entertainments Property Limited | Construction | 2009 |
| Big Blue Stow N Go Limited | Transport & logistics | 2021 |
| Big Dog Bodybuilding Ltd | Wholesale & retail | 2025 |
| Big Inns Limited | Hospitality | 2019 |
| Big Little Spaces Limited | Construction | 2026 |
| Big Little Theatre School Limited | Arts & recreation | 2003 |
| Big Mushroom Productions Limited | Information & communication | 2022 |
| Big PUB Guide Limited | Information & communication | 2018 |
| Big T (Tea) Limited | Manufacturing | 2010 |
| Bimstream AP CAD Services Ltd | Professional & scientific | 2022 |
| Binary Code Solutions Limited | Information & communication | 2023 |
| Bioshrink Ltd | Wholesale & retail | 2026 |
| Biotechmd Limited | Professional & scientific | 2023 |
| Biovision Analytics Ltd | Information & communication | 2026 |
| Birrell Operations Limited | Information & communication | 2024 |
| Birtley Investment Limited | Financial services | 2023 |
| BIS Wells Limited | Professional & scientific | 2018 |
| BJC Car Sales Limited | Wholesale & retail | 2010 |
| BJC Farm & Equine Ltd | Agriculture & fishing | 2024 |
| BKB Wimborne Ltd | Professional & scientific | 2014 |
| BKS Consultancy Ltd | Information & communication | 2012 |
| Black Dog Business Consulting Ltd | Professional & scientific | 2017 |
| Black Energy Consulting Limited | Professional & scientific | 2018 |
| Black Isle Consulting Ltd | Professional & scientific | 2022 |
| Black Lagoon Ltd | Information & communication | 2019 |
| Black Line Security Limited | Water & waste | 2019 |
| Black ROD Financial Ltd | Financial services | 2026 |
| Black Science Labs Limited | Arts & recreation | 2017 |
| Black Swan Project Management Limited | Professional & scientific | 2013 |
| Black Venn Services Limited | Information & communication | 2025 |
| Blackheath Point Limited | Information & communication | 2024 |
| Blackmore Vale Leisure Ltd | Wholesale & retail | 2007 |
| Blackrock Life Management Ltd | Professional & scientific | 2010 |
| Blackstar Pictures Limited | Professional & scientific | 2017 |
| Blackwood Homes Limited | Real estate | 2016 |
| Blainey Analytics Limited | Professional & scientific | 2024 |
| Blakestone Consulting Limited | Information & communication | 2024 |
| Blanchards Bailey Financial Services Limited | Professional & scientific | 2011 |
| Blandford Cabs Ltd | Transport & logistics | 2021 |
| Blandford Drains Ltd | Water & waste | 2016 |
| Blazeout Ltd | Professional & scientific | 2019 |
| Blend Hair Limited | Other services | 2021 |
| Bliss Construction Limited | Professional & scientific | 1991 |
| Bliss Construction Management Limited | Professional & scientific | 2000 |
| Bliss Development Limited | Professional & scientific | 2000 |
| Bliss Group Limited | Professional & scientific | 2001 |
| Bliss Holdings Limited | Professional & scientific | 2000 |
| Bliss Homes Limited | Construction | 2000 |
| Bliss Interior Systems Limited | Extraterritorial | 1991 |
| Blitterbyte Consulting Limited | Information & communication | 2024 |
| Block a (1 - 7) Indigo Mews RTM Company Limited | Households | 2016 |
| Block Chalk Services Limited | Professional & scientific | 2025 |
| Blockchain Today Ltd | Information & communication | 2020 |
| Blocked Drains Limited | Water & waste | 2017 |
| Bloom Cleaning Ltd | Administrative & support | 2018 |
| Blossom Solutions Limited | Information & communication | 2011 |
| Blossoms Day Nursery Corfe Mullen Ltd | Health & social care | 2018 |
| BLP Wealth Management Ltd | Financial services | 2020 |
| Blue Cave Consulting Limited | Professional & scientific | 2022 |
| Blue Change Limited | Professional & scientific | 2016 |