| Beverley Analytical Laboratories Limited | Professional & scientific | 1975 |
| Beyond Holdings Limited | Information & communication | 2013 |
| BG Europa (UK) Limited | Manufacturing | 1988 |
| BH Ltd | Extraterritorial | 2024 |
| Bibs N’ Bobs Ltd | Wholesale & retail | 2025 |
| Bilali Hand Car Wash Ltd | Administrative & support | 2016 |
| Biocare Waste Limited | Extraterritorial | 2025 |
| Biron Associates Ltd | Professional & scientific | 2009 |
| Birstar Limited | Professional & scientific | 2003 |
| BK Paragliding Ltd | Arts & recreation | 2024 |
| BL Ltd | Extraterritorial | 2009 |
| Black Bear Court Association Limited | Households | 1985 |
| Black Lotus Financial Services Limited | Professional & scientific | 2022 |
| Black Type Accountancy Limited | Professional & scientific | 2006 |
| Blackboard Catering Limited | Hospitality | 2013 |
| Blacktype Stallions Limited | Agriculture & fishing | 2015 |
| Blaine's Mechanics Ltd | Wholesale & retail | 2026 |
| Blakes Decorators Limited | Construction | 1997 |
| Blandford Bloodstock Limited | Agriculture & fishing | 2001 |
| BLD Cafe Limited | Hospitality | 2016 |
| Blenchi Studios Ltd | Information & communication | 2022 |
| BLG Real Estate Investments Limited | Real estate | 2025 |
| Blue Oyster Bar Limited | Construction | 2018 |
| Blue Research Limited | Extraterritorial | 2002 |
| Blue Smart Tech Ltd | Wholesale & retail | 2025 |
| Blythburgh Inn Ltd | Hospitality | 2014 |
| BNL Home Grown Ltd | Agriculture & fishing | 2020 |
| BNR Management Ltd | Hospitality | 2024 |
| BO Limited | Extraterritorial | 2007 |
| BOA Nova Bloodstock Limited | Information & communication | 2011 |
| BOB Jones Transport Ltd | Transport & logistics | 2014 |
| Bodycare Clinic Newmarket Limited | Health & social care | 2023 |
| Bogdan Baluta Limited | Health & social care | 2025 |
| Bonaclean Limited | Administrative & support | 2010 |
| Bonbonbazaar Limited | Wholesale & retail | 2025 |
| Bonito Books Ltd | Information & communication | 2025 |
| Bonza Creations Ltd | Manufacturing | 2025 |
| Boyce AIM Limited | Administrative & support | 2005 |
| Boyce Equities Limited | Administrative & support | 2001 |
| Boyce Investment Group Limited | Administrative & support | 2005 |
| Boyce Investments Limited | Administrative & support | 2001 |
| BPL Restaurants Ltd | Professional & scientific | 2022 |
| BQ Ltd | Extraterritorial | 2020 |
| Bracing Care Ltd | Wholesale & retail | 2020 |
| Brackley Investco Ltd | Financial services | 2024 |
| Bradford Electrical Limited | Construction | 2007 |
| Brailes I.T. Services Limited | Information & communication | 2003 |
| Brake Farm Yaxham Limited | Agriculture & fishing | 2021 |
| Brambleton's Limited | Construction | 2023 |
| Brazierpubs Ltd | Hospitality | 2026 |
| Brazuca Market Ltd | Hospitality | 2026 |
| Breadline 24 Ltd | Hospitality | 2024 |
| Bren Pauls Beauty Ltd | Other services | 2025 |
| Brides by Solo Limited | Wholesale & retail | 2022 |
| Bridge Contracting Services Ltd | Construction | 2020 |
| Bridge Farms Contracting Limited | Administrative & support | 2009 |
| Bridgegate Property CSC Ltd | Real estate | 2000 |
| Bridgeo Co Ltd | Hospitality | 2016 |
| Bridlemere Residents Association Limited | Real estate | 1966 |
| Bright Green Ecology Limited | Professional & scientific | 2014 |
| Bright Green Environmental Ltd | Professional & scientific | 2016 |
| Bright Green Property Limited | Professional & scientific | 2014 |
| Bright IVY Ltd | Wholesale & retail | 2023 |
| Brightday Electrical Limited | Construction | 2025 |
| Brightside 21 Limited | Hospitality | 2023 |
| Broadhurst Agency UK Limited | Agriculture & fishing | 2023 |
| Broads Road Business Park Management Company Limited | Professional & scientific | 1997 |
| Brocklesby Property Ltd | Real estate | 2020 |
| Bronkhorst (UK) Limited | Manufacturing | 2002 |
| Brook Stud Bloodstock Limited | Agriculture & fishing | 2002 |
| Brookside Stud Limited | Administrative & support | 1998 |
| Brow Mentoring Limited | Education | 2025 |
| Browns (Holdings) Ltd | Extraterritorial | 2007 |
| Browns Chilled Distribution Limited | Extraterritorial | 1994 |
| BRS Education Limited | Education | 2014 |
| BRS Training Limited | Administrative & support | 1998 |
| Buchi UK Limited | Wholesale & retail | 1999 |
| Bueno Steakhouse Ltd | Hospitality | 2025 |
| Bulldog Construction & Development Limited | Construction | 2018 |
| Burden LEE Equine Ltd | Agriculture & fishing | 2024 |
| Burdett King Accountancy Limited | Professional & scientific | 2013 |
| Bureside Inns Ltd | Hospitality | 2022 |
| Burnt House Investments Limited | Professional & scientific | 2007 |
| Burstone Developments Ltd | Construction | 2018 |
| Bushel Inn 23 Ltd | Hospitality | 2023 |
| Bute House Aesthetics Ltd | Other services | 2019 |
| Butterworth & SON Limited | Wholesale & retail | 1976 |
| BV Ltd | Extraterritorial | 2009 |
| BW Ltd | Extraterritorial | 2022 |
| By-Pass Nurseries Limited | Wholesale & retail | 1939 |
| Byam-Cook Surveyors Limited | Professional & scientific | 2004 |
| Byron & Co Properties Limited | Real estate | 2021 |
| C & G Building and Developments Limited | Construction | 2015 |
| C & W Automotive Ltd | Wholesale & retail | 2014 |
| C B 8 Magazines Limited | Information & communication | 2007 |
| C C Denness UK Limited | Agriculture & fishing | 2012 |
| C J Accounting Services Limited | Professional & scientific | 2002 |
| C RIX Limited | Construction | 2009 |
| C W Gooch Limited | Professional & scientific | 2014 |
| C&C Scientific Consulting Ltd | Professional & scientific | 2022 |