| Buno Contracting Limited | Financial services | 2024 |
| Buntyferret Investments Limited | Financial services | 2019 |
| Bunz 4 U Ltd | Hospitality | 2024 |
| Burchell Motorhome Investment Ltd | Administrative & support | 2024 |
| Burchell Property Investment Limited | Real estate | 2016 |
| Burcote Consultancy Limited | Real estate | 2019 |
| Burcote Property Limited | Real estate | 2017 |
| Burcote Wind Hotbed Limited Partnership | | 2009 |
| Burcotecourt Development Limited | Construction | 2017 |
| Burcott Consulting Limited | Real estate | 2019 |
| Bure Cards Limited | Wholesale & retail | 2026 |
| Burge Hughes Walsh Limited | Professional & scientific | 2017 |
| Burgess Hill Management Ltd | Households | 2024 |
| Burhall and Partners Ltd | Professional & scientific | 2025 |
| Burhall Sports Ltd | Wholesale & retail | 2025 |
| Buri & Co. Ltd | Financial services | 2018 |
| Burleigh Estates (Holdings) Limited | Real estate | 1996 |
| Burleigh Estates Limited | Real estate | 2004 |
| Burley Rail Group Ltd | Professional & scientific | 2023 |
| Burlington Construction (Bucks) Limited | Construction | 2001 |
| Burning Inspirations Limited | Construction | 2002 |
| Burning Sounds Recordings Limited | Arts & recreation | 1984 |
| Burns Building Solutions Ltd | Construction | 2020 |
| Burns International Pension Trustee Limited | Professional & scientific | 2025 |
| Burns Property Solutions Limited | Real estate | 2018 |
| Burpham and Warningcamp PUB Company Ltd | Administrative & support | 2013 |
| Burrows and Riley Limited | Health & social care | 2026 |
| Burtenshaw Building Services Limited | Other services | 2012 |
| Burton Bandini Ltd | Professional & scientific | 2007 |
| Burton on Trent Social Ltd | Information & communication | 2025 |
| Burton Read Associates Limited | Education | 2010 |
| Burwash FHR LLP | | 2022 |
| Buryfield Grange Limited | Financial services | 2002 |
| BUS Stop Drop-In & Counselling Limited | Health & social care | 2011 |
| Bushey Blinds Limited | Wholesale & retail | 2013 |
| Busibud Ltd | Information & communication | 2017 |
| Business Advisory and Support Services Ltd | Financial services | 2020 |
| Business Analysis & Accounting Services Limited | Professional & scientific | 2012 |
| Business Analytics Ltd | Professional & scientific | 2022 |
| Business and Technology International Campus UK Limited | Administrative & support | 2015 |
| Business Computing Consultancy Ltd | Information & communication | 2014 |
| Business Connection PTE Ltd | Information & communication | 2022 |
| Business Improvement Specialists Limited | Professional & scientific | 2004 |
| Business Insight Plus Limited | Administrative & support | 2015 |
| Business Intelligence Data Consulting Services Ltd | Information & communication | 2014 |
| Business Media Network Limited | Information & communication | 2011 |
| Business NET Solutions Limited | Information & communication | 2004 |
| Business NLP Ltd | Professional & scientific | 2001 |
| Business Professional Advisers Limited | Financial services | 1994 |
| Business Technology Leaders Limited | Professional & scientific | 2024 |
| Business Watts Solutions Ltd | Information & communication | 2026 |
| Business World Services (1995) Limited | Administrative & support | 1995 |
| Businevo Limited | Professional & scientific | 2025 |
| Buskers Brunch Limited | Hospitality | 2015 |
| Busy BEE Works Ltd | Wholesale & retail | 2024 |
| Busyme Ltd | Information & communication | 2012 |
| Butler & Grace Ltd | Manufacturing | 2014 |
| Butler and Lyon Limited | Real estate | 2025 |
| Butlers Transport Ltd | Transport & logistics | 2025 |
| Butterfield Estates Limited | Real estate | 2005 |
| Butterfield's Recovery Ltd. | Wholesale & retail | 1975 |
| Butterflies Dental Clinic (Holdings) Ltd | Health & social care | 2022 |
| Butterflies Dental Clinic Ltd | Health & social care | 2006 |
| Butterfly Bathrooms Limited | Construction | 2026 |
| Buttons Early Years Ltd | Education | 2019 |
| Buttons Preschools Limited | Health & social care | 2012 |
| Buttons Property Management Limited | Extraterritorial | 2008 |
| Buttoo & Sons Ltd | Real estate | 2025 |
| Butts Park Homes LLP | | 2021 |
| Buy Sell and Loan Ltd | Wholesale & retail | 2021 |
| Buy to LET Mk.Com Limited | Real estate | 2009 |
| Buy to LET Properties Limited | Real estate | 2018 |
| Buyabbq.Com Ltd | Wholesale & retail | 2020 |
| Buzby Properties Ltd | Real estate | 2023 |
| Buzz Apparel Ltd | Wholesale & retail | 2018 |
| Buzz Property Management and Consultancy Limited | Real estate | 2015 |
| Buzzard Builders Ltd | Construction | 2023 |
| BV Global Ltd. | Wholesale & retail | 2015 |
| BW Glazing and Locks Ltd | Construction | 2025 |
| BW Health Haven Ltd | Health & social care | 2022 |
| BWC Greenhouses Ltd | Manufacturing | 2005 |
| BWC Manufacturing Limited | Financial services | 2020 |
| BWC Profiles Ltd | Manufacturing | 2012 |
| BWC Property Ltd | Real estate | 2022 |
| BWL Services Limited | Professional & scientific | 2018 |
| Bwlcare Ltd | Health & social care | 2020 |
| BWS International Limited | Mining & quarrying | 1998 |
| BY Amey Ltd | Other services | 2025 |
| BY Doner MK Ltd | Hospitality | 2024 |
| BY the Sea Shore Partnerships Limited | Health & social care | 2026 |
| BY U for YOU Limited | Professional & scientific | 2022 |
| Byard Management Limited | Real estate | 1981 |
| BYD Consultancy Ltd | Professional & scientific | 2016 |
| Bymead House Limited | Health & social care | 2007 |
| BYP Properties UK Ltd | Real estate | 2025 |
| BYR Limited | Other services | 2018 |
| Byrex Solutions Limited | Information & communication | 2020 |
| Byrne Williams Limited | Financial services | 1998 |
| Byron Hayter Holdings Ltd | Financial services | 2022 |
| Byte Analytics Private Limited | Information & communication | 2026 |