| BH Engineering & Mechanical Ltd | Professional & scientific | 2022 |
| BHL Finance Limited | Professional & scientific | 2022 |
| Bieluch Transport Ltd | Transport & logistics | 2016 |
| Big Dish Energy Limited | Hospitality | 2022 |
| Big Event Screens Limited | Professional & scientific | 2016 |
| Big Red BUS Events Limited | Hospitality | 2024 |
| Big Village Consulting Limited | Professional & scientific | 2009 |
| Biison Ltd | Construction | 2019 |
| Bill Ashley Ltd | Professional & scientific | 2013 |
| Billing Tackle Grantham Ltd | Wholesale & retail | 2025 |
| Billing Tackle Limited | Wholesale & retail | 2023 |
| Billing Tackle Northampton Ltd | Wholesale & retail | 2025 |
| Billing Tackle Shops Ltd | Wholesale & retail | 2025 |
| Billion Records Ltd | Extraterritorial | 2024 |
| Bingham Ground Services Limited | Construction | 2025 |
| Biodiversify Ltd | Professional & scientific | 2018 |
| Biosciences Biosci Limited | Professional & scientific | 2016 |
| Biospectrum Holdings Limited | Financial services | 2025 |
| Biospectrum Limited | Health & social care | 2017 |
| Birkland Limited | Real estate | 2019 |
| Biscuit Investments Ltd | Real estate | 2013 |
| BJ Smith Limited | Administrative & support | 2003 |
| BL Lane Limited | Households | 2021 |
| Black Cat Electrical Ltd | Construction | 2025 |
| Black Cat Property Services Limited | Construction | 2021 |
| Black Panther Fireworks Ltd | Wholesale & retail | 2020 |
| Black Stallion Limited | Construction | 2014 |
| Black Vanilla Catering Limited | Hospitality | 2019 |
| Blagg & Johnson Limited | Manufacturing | 1971 |
| Blake House Consulting Ltd | Professional & scientific | 2019 |
| Blardony Limited | Administrative & support | 2018 |
| Blenheim Agricultural Limited | Agriculture & fishing | 2026 |
| Blissful Baby Ltd | Wholesale & retail | 2023 |
| Block Smart Consultants Limited | Professional & scientific | 2026 |
| Block Wills & Trusts Limited | Professional & scientific | 2006 |
| Bloodheart Ltd | Health & social care | 2019 |
| Blossom Property Developments Ltd | Real estate | 1999 |
| Blue Compliance Limited | Wholesale & retail | 2008 |
| Blue Foam HCW Ltd | Administrative & support | 2025 |
| Blue Phoenix House Ltd | Extraterritorial | 2021 |
| Blue Sky Properties (Midlands) Limited | Hospitality | 2023 |
| Bluecrest Property Group Ltd | Construction | 2026 |
| Blueprint Gaming Ltd | Information & communication | 2007 |
| Blueprint Operations Limited | Information & communication | 2015 |
| Blueprint Technologies Ltd | Information & communication | 2016 |
| BM 40 Ltd | Education | 2024 |
| BNS Contracting Ltd | Construction | 2026 |
| Board Envelopes Ltd | Extraterritorial | 2012 |
| Boas Joinery Ltd | Manufacturing | 2022 |
| Bobble Solutions Ltd | Information & communication | 2016 |
| Bodin Transport Ltd | Administrative & support | 2017 |
| Body and Soul Therapy Limited | Health & social care | 2001 |
| Bolt Computers Limited | Manufacturing | 2018 |
| Bolton Priestley Ltd. | Professional & scientific | 1994 |
| Bond Inspection Ltd | Professional & scientific | 2026 |
| Bonsers Restoration Limited | Construction | 2006 |
| Boodog Projects Ltd | Construction | 1995 |
| Bookkeeping Services (Derby) Limited | Professional & scientific | 2003 |
| Boolevard Cosmetics Limited | Wholesale & retail | 2012 |
| Bottrill Properties Ltd | Real estate | 2020 |
| Boughton Development Projects Limited | Construction | 2019 |
| Boughton Service Centre Limited | Wholesale & retail | 2016 |
| Boutique Online Limited | Wholesale & retail | 2015 |
| BOW Avenue Clothing Ltd | Wholesale & retail | 2026 |
| Bowbridge Holdings Limited | Administrative & support | 2007 |
| Boxx Solutions Ltd | Administrative & support | 2011 |
| Bpls Developments Ltd | Construction | 2016 |
| BPS Rentals Limited | Real estate | 2025 |
| BR Inspections Ltd | Manufacturing | 2022 |
| Brackenfield View Management Company Limited | Households | 2008 |
| Brackenxcapes Ltd | Hospitality | 2021 |
| Brackston Survey Ltd | Professional & scientific | 2019 |
| Brainerd Holdings Limited | Financial services | 2022 |
| Brains at Work Academy Ltd | Other services | 2026 |
| Brambleside Holdings Ltd | Real estate | 2021 |
| Brambleside Property Developments Ltd | Construction | 2018 |
| Brambly Hedge Construction Ltd | Construction | 2011 |
| Brand Newark Ltd | Professional & scientific | 2020 |
| Braston UK Services Limited | Health & social care | 2013 |
| Brava ACC Ltd | Wholesale & retail | 2025 |
| Brava Commercial Ltd | Wholesale & retail | 2025 |
| Brava Comms TEL Ltd | Wholesale & retail | 2025 |
| Brava Constant Ltd | Wholesale & retail | 2025 |
| Braveo Business Ltd | Wholesale & retail | 2025 |
| Bravo Business Ltd | Wholesale & retail | 2025 |
| Bravo Express Trading Ltd | Wholesale & retail | 2025 |
| Bravo Online Commerce Ltd | Wholesale & retail | 2025 |
| Brayshaw N Limited | Administrative & support | 2015 |
| Breakout Brands Ltd | Wholesale & retail | 2026 |
| Breeze Compliance Limited | Administrative & support | 2026 |
| Brela Flooring Ltd | Construction | 2016 |
| Brendan Doherty Ltd | Construction | 2026 |
| Brian Barton Building and Renovations Ltd | Construction | 2019 |
| Brick Vault Limited | Manufacturing | 2024 |
| Bridge Together Ltd | Public administration | 2019 |
| Bridgford Capital Limited | Wholesale & retail | 2024 |
| Bridje Studios Limited | Wholesale & retail | 2025 |
| Bridle International Ltd | Education | 2006 |
| Briggs Metals Limited | Water & waste | 2006 |
| Bright Light Management Consultant Ltd | Professional & scientific | 2023 |