| Buran Alliance PC | | 2017 |
| Buraqhospitality Ltd | Hospitality | 2026 |
| Burbaxy Ltd | Wholesale & retail | 2024 |
| Burdila Ltd | Construction | 2016 |
| Burdog Ltd | Hospitality | 2018 |
| Bureau of International Standard Limited | Other services | 2017 |
| Burford Ltd | Real estate | 2015 |
| Burford Property Enterprises Ltd | Real estate | 2025 |
| Burgandyred Recruits Ltd | Administrative & support | 2022 |
| Burgeon Limited | Construction | 2004 |
| Burgeoning Concepts Limited | Information & communication | 2024 |
| Burger Services Limited | Hospitality | 2022 |
| Burger Xpress Ltd | Hospitality | 2016 |
| Burgerbossuk Ltd | Hospitality | 2025 |
| Burgess Recycling Limited | Manufacturing | 2010 |
| Burgess Solutions Ltd | Professional & scientific | 2024 |
| Burghside Management Company Ltd. | Households | 1999 |
| Burhani General Trading Ltd | Wholesale & retail | 2023 |
| Burke & SON Commercial Limited | Households | 2025 |
| Burkes Home Improvements Ltd | Construction | 2024 |
| Burl and Beam Limited | Manufacturing | 2023 |
| Burley FOX Limited | Financial services | 2013 |
| Burlington Creative Media Limited | Professional & scientific | 2025 |
| Burlington U.K. Limited | Professional & scientific | 2023 |
| Burlow Consulting Ltd | Extraterritorial | 2020 |
| Burmanovak Limited | Other services | 2008 |
| Burnd Ltd | Information & communication | 2024 |
| Burnelron Properties Limited | Real estate | 2025 |
| Burnt Bread Limited | Hospitality | 2024 |
| Burnt Bunny Limited | Hospitality | 2025 |
| Burrito Picante Ltd | Hospitality | 2019 |
| Burro Media Limited | Information & communication | 2023 |
| Bursa Digital Limited | Information & communication | 2025 |
| Burton-Dadd & Williams Property Ltd | Real estate | 2025 |
| Burtonwood House Limited | Other services | 2024 |
| Bus-Trs Ltd | Transport & logistics | 2019 |
| BUS4U Travel Ltd | Transport & logistics | 2022 |
| Bushhill Plant Ltd | Construction | 2020 |
| Bushido Films Ltd | Information & communication | 2020 |
| Bushrod Floortech Limited | Construction | 2015 |
| Bushtec Engineering & Fabrication Ltd | Professional & scientific | 2019 |
| Busif (UK) Crop Nutrition Co., Ltd | Extraterritorial | 2017 |
| Business Accounts Spot Ltd | Professional & scientific | 2018 |
| Business Adventures Worldwide Ltd | Wholesale & retail | 2023 |
| Business Advice Mentoring (Wales) Limited | Professional & scientific | 2017 |
| Business Advisory Holding 2 Ltd | Real estate | 2025 |
| Business Advisory Holding 3 Ltd | Real estate | 2025 |
| Business and Accountancy Solutions Ltd | Professional & scientific | 2017 |
| Business Connect Networking Ltd | Other services | 2020 |
| Business Consultancy Management Ltd | Professional & scientific | 2024 |
| Business Consultation Ltd | Education | 2019 |
| Business Consulting London Limited | Professional & scientific | 2020 |
| Business Credit Management Services Limited | Extraterritorial | 2007 |
| Business Development Services Europe Ltd | Administrative & support | 2021 |
| Business Elements Limited | Administrative & support | 2019 |
| Business Energy Advisors (Balton) Limited | Wholesale & retail | 2025 |
| Business Energy Direct Ltd | Professional & scientific | 2013 |
| Business EYE Security Services Ltd | Financial services | 2022 |
| Business Finance and Leasing Limited | Financial services | 2014 |
| Business Flow Limited | Information & communication | 2024 |
| Business Growth Genius Ltd | Information & communication | 2023 |
| Business Knowlge International College Ltd | Education | 2025 |
| Business Land PC | | 2017 |
| Business Language Services Limited | Professional & scientific | 1993 |
| Business Lunch Company Catering Limited | Hospitality | 2009 |
| Business Machine Realisations Limited | Manufacturing | 1985 |
| Business Management Consultancy Ltd | Professional & scientific | 2021 |
| Business Management School of London Limited | Education | 2019 |
| Business Marketing 247 Ltd | Wholesale & retail | 2021 |
| Business Migration Services Ltd | Professional & scientific | 2015 |
| Business Officials Ltd | Hospitality | 2024 |
| Business Pathfinders Ltd | Professional & scientific | 2023 |
| Business Power Solutions Ltd | Information & communication | 2018 |
| Business Recycling Group Ltd | Water & waste | 2023 |
| Business Requirements Ltd | Information & communication | 2025 |
| Business Script Academy Ltd | Information & communication | 2025 |
| Business Start UP Coaching & Mentoring Service Ltd | Administrative & support | 2019 |
| Business Technology Solutions Worldwide LP | | 2014 |
| Business Thing Ltd | Other services | 2024 |
| Business Trads GB Ltd. | Information & communication | 2019 |
| Business Visual Limited | Professional & scientific | 2002 |
| BUSINESS24 | Information & communication | 2021 |
| Businessgen Limited | Information & communication | 2008 |
| Busla Education and Training Services Ltd | Professional & scientific | 2023 |
| Bust Canton Barbar Shop Ltd | Other services | 2022 |
| Busta Ltd | Construction | 2015 |
| Buster Sound Ltd | Information & communication | 2011 |
| Busty GAL Ltd | Manufacturing | 2025 |
| Busy Secretary Service Limited | Extraterritorial | 2022 |
| Busystartups Ltd | Information & communication | 2019 |
| Butcher & Brew Limited | Wholesale & retail | 2020 |
| Butchers Hook Food Services Ltd | Manufacturing | 2020 |
| Bute Care Services Ltd | Professional & scientific | 2026 |
| Bute Energy (Cambria) Limited | Energy | 2020 |
| Bute Energy Construction Holdings Limited | Energy | 2025 |
| Bute Energy Development Holdings Limited | Financial services | 2021 |
| Bute Energy Limited | Energy | 2020 |
| Bute Energy NB Limited | Energy | 2026 |
| Bute Energy Power UP Limited | Administrative & support | 2025 |
| Bute Property (Cardiff) Limited | Construction | 2016 |