| Belford Handmade Interiors Ltd | Manufacturing | 2024 |
| Bellagio Marble Ideas Limited | Manufacturing | 2021 |
| Bellagio Stone Limited | Manufacturing | 2005 |
| BEN Mackey Online Coaching Ltd | Health & social care | 2020 |
| BEN Mantle Limited | Administrative & support | 2010 |
| Benavent Consulting Limited | Information & communication | 2003 |
| Benehealth Ltd | Health & social care | 2026 |
| Benfield Custom Homes Limited | Construction | 2017 |
| Benfield Group Limited | Manufacturing | 1998 |
| Bennetts Bricklaying & Construction Limited | Construction | 2001 |
| Beone Hub Ltd | Information & communication | 2025 |
| Beone Ltd | Information & communication | 2025 |
| Berkley Property Services Ltd | Real estate | 2018 |
| Berry's Carpets & Floors Limited | Construction | 2022 |
| Bespoke Mortgage Solutions Limited | Financial services | 2018 |
| Bespoke Wheels Limited | Wholesale & retail | 2003 |
| Bessacarr Publications Limited | Manufacturing | 2003 |
| Best Fire and Security Limited | Administrative & support | 2024 |
| Bestodeck Limited | Financial services | 1982 |
| Bethanyrosefit Ltd | Arts & recreation | 2026 |
| Better Air UK Limited | Administrative & support | 2018 |
| Betteridge Place Management Company Limited | Professional & scientific | 1996 |
| Beyond Brand Group Limited | Professional & scientific | 2016 |
| Beyond Electrical Ltd | Construction | 2023 |
| Beyond the Agency Ltd | Other services | 2025 |
| Beyond the Bump Limited | Real estate | 2024 |
| Beyond the Bump UK CIC | Education | 2025 |
| BFF Solutions Ltd | Professional & scientific | 2026 |
| BG-26 Limited | Professional & scientific | 2021 |
| Bicycle Repairmen Ltd | Manufacturing | 2022 |
| Biddulph Property Investments Limited | Real estate | 2004 |
| Big Easy Property Limited | Administrative & support | 2006 |
| Bigbrother Technology Limited | Wholesale & retail | 2026 |
| Bigid UK Ltd | Information & communication | 2018 |
| Bigshield Limited | Professional & scientific | 1986 |
| Bigthinx Limited | Information & communication | 2022 |
| Bijou Residences Limited | Construction | 2017 |
| Bike Fest Live Limited | Other services | 2017 |
| Bill Young Agriculture Ltd | Agriculture & fishing | 2024 |
| Binderholz UK Ltd | Administrative & support | 2016 |
| Biogaia UK Limited | Wholesale & retail | 2021 |
| Biolyz UK Limited | Professional & scientific | 2026 |
| Biotech Design and Validation Ltd. | Manufacturing | 1995 |
| Bird West Property Investments Limited | Real estate | 2022 |
| BIZ Growth Coaching Ltd | Administrative & support | 2022 |
| Bizportal Limited | Information & communication | 2023 |
| Bizzy Balloons LLP | | 2015 |
| Bjorn Borg UK Limited | Extraterritorial | 2010 |
| BKM Lettings Ltd. | Real estate | 2009 |
| Bknk Limited | Other services | 2021 |
| BL Housestyle Limited | Real estate | 2013 |
| Black & White Management Associates Ltd | Other services | 2024 |
| Black Button Militaria Ltd | Wholesale & retail | 2022 |
| Black Cat Entertainment Ltd | Wholesale & retail | 2017 |
| Black Crow Wheel Technology Ltd | Wholesale & retail | 2023 |
| Black Onyx Properties Ltd | Real estate | 2022 |
| Blackdale Developments Limited | Real estate | 2022 |
| Blackdog Cloud Technologies Limited | Information & communication | 2020 |
| Blackfire Films Ltd | Information & communication | 2016 |
| Blackthorn Blocks 3 & 4 Valiant Fields Residents Management Company Ltd | Households | 2025 |
| Bladon Technologies Limited | Manufacturing | 2024 |
| Blake Court Limited | Health & social care | 1997 |
| Blank Golf Apparel Limited | Wholesale & retail | 2026 |
| Blast 'N' Prep Ltd | Manufacturing | 2018 |
| Bleasdales Limited | Administrative & support | 2008 |
| Blended Technologies Ltd | Information & communication | 2020 |
| BLJ Services Limited | Other services | 2025 |
| Blood Stock Agent Ltd | Agriculture & fishing | 2021 |
| Blooming Lotus Project CIC | Health & social care | 2025 |
| Blue Aeon Limited | Information & communication | 2020 |
| Blue Bay Building Products Limited | Wholesale & retail | 2003 |
| Blue Breaks Sports Card & Hobby Shop Ltd | Wholesale & retail | 2025 |
| Blue Gansey Consulting Ltd | Professional & scientific | 2021 |
| Blue HK Investments Ltd | Financial services | 2010 |
| Blue Mobile Systems UK Limited | Information & communication | 2011 |
| Blue Power Consulting Ltd | Information & communication | 2010 |
| Blue Tiger Systems Limited | Professional & scientific | 2006 |
| Blueberry Fudge Holdings Ltd | Financial services | 2024 |
| Bluehaus Holdings Limited | Financial services | 2024 |
| Bluehouse Builders Limited | Construction | 2017 |
| Bluehouse Landscapes and Design Ltd | Administrative & support | 2019 |
| Bluemoon Trading Limited | Wholesale & retail | 2025 |
| Blundellsands Classic Management Limited | Households | 2002 |
| BM Certification UK Limited | Professional & scientific | 2021 |
| BM Just Camps Ltd | Health & social care | 2025 |
| BMB Community Limited | Financial services | 2025 |
| BMR Contract Services Limited | Professional & scientific | 2026 |
| BMS Software Limited | Information & communication | 2022 |
| Boar & Bristle Ltd | Wholesale & retail | 2012 |
| Boat Lane Court Limited | Households | 1990 |
| Body Calibre Ltd | Health & social care | 2022 |
| Bonel & Curtis (Audio) Limited | Real estate | 1975 |
| Book Your Hols Limited | Extraterritorial | 2024 |
| Booking Boats Limited | Information & communication | 2025 |
| Bookkeeping Easy Ltd | Professional & scientific | 2020 |
| Boost Creative Ltd | Administrative & support | 2019 |
| Borton Gray Ltd | Information & communication | 2015 |
| Boston Maintenance Services Limited | Construction | 1991 |
| Botanical Brothers Ltd | Arts & recreation | 2021 |
| Boudoir Beauty Bar Limited | Other services | 2024 |