| Atlas Precision Engineering Limited | Manufacturing | 2003 |
| Atom Cabs Ltd | Transport & logistics | 2024 |
| Auberies Associates Ltd | Professional & scientific | 2026 |
| Austin Management (Europe) Limited | Arts & recreation | 2022 |
| Autipocket Limited | Information & communication | 2025 |
| Auto Loader Ltd | Water & waste | 2025 |
| AUX Import Ltd | Wholesale & retail | 2022 |
| Auxiliam Ltd | Professional & scientific | 2020 |
| Avalon Distillery Company Ltd | Manufacturing | 2015 |
| Aviation Requirements Ltd | Professional & scientific | 2003 |
| AWT Construction Ltd | Construction | 2025 |
| B&D Creative Limited | Information & communication | 2026 |
| Baba Works Limited | Extraterritorial | 2006 |
| Baboushkini Limited | Wholesale & retail | 2021 |
| Backlist Limited | Wholesale & retail | 1987 |
| Badgers Grove (Stalbridge) Limited | Households | 2022 |
| Barha Technologies Ltd | Information & communication | 2023 |
| Barton Farm Estates Limited | Construction | 2016 |
| Bay Cottages (Dorset) Limited | Hospitality | 2026 |
| Bbnt Building Services Limited | Professional & scientific | 2017 |
| Beaminster Interiors Ltd | Professional & scientific | 2024 |
| Beaufort Court Management Company Limited | Households | 1988 |
| Beckington LVA LLP | | 2024 |
| Becky Chilcott Design Limited | Arts & recreation | 2012 |
| BEE Charmed for Good Ltd. | Wholesale & retail | 2006 |
| Behind Berry Management Limited | Professional & scientific | 1989 |
| Bellavista Investments Corporation Limited | Professional & scientific | 2017 |
| Bellewether Spirits Ltd | Wholesale & retail | 2019 |
| Bellvy Ltd | Real estate | 2022 |
| Belo Creative Ltd | Professional & scientific | 2020 |
| BEN + Words Limited | Professional & scientific | 2023 |
| BEN Gilbert Ltd | Professional & scientific | 2022 |
| Bensons Fruit Juice Limited | Manufacturing | 2002 |
| Besen Limited | Wholesale & retail | 2025 |
| Bespoak Construction Ltd | Construction | 2020 |
| Bestchem Products Limited | Manufacturing | 2003 |
| Beyond Number Productions Ltd | Information & communication | 2010 |
| Beyond the Trees Consultancy LLP | | 2024 |
| BH Design Limited | Professional & scientific | 2025 |
| Bideford LVA LLP | | 2017 |
| Billitts Landscapes Ltd | Administrative & support | 2023 |
| Birch&Co Ltd | Professional & scientific | 2024 |
| Birchall Holdings Ltd | Financial services | 2020 |
| Birdland Park Holdings Limited | Financial services | 2023 |
| Birdland Park Limited | Arts & recreation | 2023 |
| Birkenhead LVA LLP | | 2017 |
| Biskup Property Maintenance Ltd | Professional & scientific | 2013 |
| Bitham Real Estate Ltd | Real estate | 2025 |
| BKJ Cleaning Limited | Administrative & support | 2002 |
| Black Shed Flowers Ltd | Other services | 2017 |
| Blackdown Investment Limited | Real estate | 2021 |
| Blackmarsh Ltd | Financial services | 2024 |
| Blackmore & Sparkford Vale Trading Limited | Wholesale & retail | 2014 |
| Blackmore Flats Limited | Households | 1991 |
| Blackstone Cross LVA LLP | | 2021 |
| Blast Skates Ltd | Wholesale & retail | 2021 |
| Blighter Ltd | Hospitality | 2024 |
| Blockhouse Building Limited | Other services | 2019 |
| Bloodstock Ltd | Agriculture & fishing | 2016 |
| Bloody Norah TV Services Ltd | Information & communication | 2021 |
| Blue Electric Limited | Construction | 2020 |
| Blue Ribbon Limited | Professional & scientific | 1993 |
| Blue Sky Tutoring Ltd | Extraterritorial | 2018 |
| Blue Spruce Properties Limited | Administrative & support | 2015 |
| Bluebean Publishing Ltd | Administrative & support | 2004 |
| Bmgt Property Ltd | Real estate | 2025 |
| Boston LVA LLP | | 2017 |
| Bosun Distillery Ltd | Manufacturing | 2021 |
| Bowen Roofing Ltd | Construction | 2011 |
| BOZ Consulting Ltd | Wholesale & retail | 2020 |
| Brad's Classic & Specialist Cars Limited | Wholesale & retail | 2021 |
| Braunton LVA LLP | | 2023 |
| Breakthrough Approach Ltd | Education | 2023 |
| Brecon House Management Company Limited | Real estate | 2001 |
| Brian and Brian Ltd | Transport & logistics | 2017 |
| Bridport LVA LLP | | 2014 |
| Bridport Timber & Flooring Limited | Construction | 2011 |
| Bright Blue GAS Ltd | Construction | 2013 |
| Bright Start Mortgages Limited | Administrative & support | 2015 |
| Brindley James Holdings Ltd | Financial services | 2019 |
| Brindley James Limited | Construction | 2011 |
| Bring Home Power Ltd | Wholesale & retail | 2024 |
| Brintonby Limited | Real estate | 1983 |
| Brisca (F2) Limited | Arts & recreation | 1995 |
| Bristol Road Garage Limited | Wholesale & retail | 2018 |
| Broad Oak Retail Limited | Wholesale & retail | 2018 |
| Broadclyst LVA LLP | | 2021 |
| Broadmayne LVA LLP | | 2021 |
| Brooks Fabrications Limited | Manufacturing | 2017 |
| Brotherwood Automobility Limited | Manufacturing | 1978 |
| Brotherwood Holdings Limited | Financial services | 2017 |
| Bryan C. Cooper Limited | Construction | 1975 |
| Bs.Haus Limited | Professional & scientific | 2022 |
| Buccaneer Motor Company Limited | Wholesale & retail | 2005 |
| Buckshaw Land Limited | Real estate | 2011 |
| Building Data Services Ltd | Information & communication | 2023 |
| Burrow Environmental Ltd | Manufacturing | 2017 |
| Burrow Environmental Servicing Ltd | Professional & scientific | 2023 |
| Busch Properties Limited | Real estate | 2016 |
| Butleigh LVA LLP | | 2017 |