| B.B. Security Systems Ltd | Administrative & support | 2024 |
| B.D.A. (Initiatives) Limited | Wholesale & retail | 1994 |
| B.D.K. Solutions Limited | Information & communication | 1989 |
| B.E.C Building Services Ltd | Construction | 2019 |
| B.G Parris Electrical Ltd | Construction | 2016 |
| B.I.G Brand Impact GRP Limited | Extraterritorial | 2014 |
| B.Solomon Limited | Construction | 2018 |
| B2B Solutions Ltd | Information & communication | 2018 |
| B3 Apparel Ltd | Manufacturing | 2024 |
| B6 (UK) Ltd | Manufacturing | 2005 |
| BA Art Build Ltd | Construction | 2025 |
| BA Car Sales Ltd | Wholesale & retail | 2021 |
| BA International Foods Ltd | Manufacturing | 2025 |
| Baaki Solutions Ltd | Information & communication | 2020 |
| Baal-Perazim Consulting Limited | Information & communication | 2013 |
| Baan Siam Thai Therapies Ltd | Health & social care | 2025 |
| Baba Malik Limited | Information & communication | 2023 |
| Babaj Ltd | Transport & logistics | 2018 |
| Babar & Nazia Ltd | Real estate | 2023 |
| Baba’S Enterprise Ltd | Construction | 2025 |
| Babbie Mojo Limited | Health & social care | 2022 |
| Babble-Translate Ltd | Information & communication | 2025 |
| Babe & Beyond Ltd | Information & communication | 2025 |
| Babicka Vodka (International) Limited | Wholesale & retail | 2013 |
| Baby Bird Consulting Limited | Administrative & support | 2016 |
| Baby Moments Limited | Health & social care | 2013 |
| Baby Swimming North Wessex LLP | | 2024 |
| Babz Executive Travels Ltd | Transport & logistics | 2016 |
| Babz Ltd | Health & social care | 2024 |
| BAC 2 Basics Accounting Limited | Professional & scientific | 2017 |
| BAC 2 Basics Limited | Administrative & support | 2013 |
| Bacchus Gaudium Ltd | Hospitality | 2012 |
| Bace Line Construction Limited | Construction | 2014 |
| Baci Brickworks Limited | Construction | 2022 |
| Baci Estates Limited | Real estate | 2025 |
| Back to Front (UK) Ltd | Other services | 2014 |
| Back to Harmony Ltd | Education | 2022 |
| Backroom Partners Ltd | Professional & scientific | 2018 |
| Backspace Home Limited | Real estate | 2020 |
| Baconfat Limited | Information & communication | 2014 |
| Bada Bang Properties Ltd | Real estate | 2025 |
| Badabinks Limited | Real estate | 2022 |
| Badan Limited | Professional & scientific | 2025 |
| Badf Solutions Ltd | Professional & scientific | 2018 |
| Badulet Engineering Ltd Limited | Manufacturing | 2025 |
| BAE Food & Wine Store Limited | Wholesale & retail | 2015 |
| Baer Consulting Limited | Professional & scientific | 2025 |
| Bagaara Reading Ltd | Hospitality | 2024 |
| Bagga Sons Ltd | Real estate | 2024 |
| Bags Direct International Limited | Wholesale & retail | 1961 |
| Baheer Shan Ltd | Professional & scientific | 2013 |
| Bahman Limited | Professional & scientific | 2020 |
| Baice Ltd | Education | 2021 |
| Bailey Green Travel Ltd | Administrative & support | 2025 |
| Baiomics Ltd | Professional & scientific | 2022 |
| Bait Taha Ltd | Real estate | 2025 |
| Bajwa and SON Limited | Transport & logistics | 2013 |
| Bajwa Export Limited | Wholesale & retail | 2025 |
| Bakea Ltd | Health & social care | 2022 |
| Baked Catering Ltd | Hospitality | 2023 |
| Baked in Berkshire Limited | Wholesale & retail | 2026 |
| Baked Ltd | Hospitality | 2025 |
| Baker Applications Limited | Information & communication | 2014 |
| Baker Refractories Limited | Professional & scientific | 1992 |
| Baker Rental Properties Limited | Real estate | 2013 |
| Baker Software Limited | Information & communication | 2022 |
| Baker Station Ltd | Manufacturing | 2013 |
| Baker Street Publishing Ltd | Information & communication | 2019 |
| Bakeria Ltd | Information & communication | 2017 |
| Bakery House Ltd | Hospitality | 2015 |
| Baksh Catering Limited | Hospitality | 2009 |
| Baku Kyiv Retail Limited | Wholesale & retail | 2025 |
| Baladart Holdings Limited | Financial services | 2026 |
| Baladine Construction Ltd | Construction | 2024 |
| Balaji BI Solutions Limited | Information & communication | 2024 |
| Balaji Investors Limited | Real estate | 2025 |
| Balaji Ventures Limited | Real estate | 2024 |
| Balanced Functional Health Clinic Ltd | Health & social care | 2021 |
| Balanced Insight Ltd | Wholesale & retail | 2020 |
| Balanchi London Clothing Ltd | Wholesale & retail | 2018 |
| Balasoft Limited | Real estate | 1993 |
| Balclutha Holdings Limited | Financial services | 2021 |
| Balforton Developments Ltd | Construction | 2019 |
| Balfours FM Consultancy Ltd | Administrative & support | 2015 |
| Balgamber Cottages Ltd | Real estate | 2025 |
| Balgamber Ltd | Real estate | 2024 |
| Bali Brothers Brickworks Ltd | Construction | 2024 |
| Ball Coatings Ltd | Construction | 2018 |
| Ball Green Energy Storage Limited | Energy | 2024 |
| Balloons 101 Ltd | Administrative & support | 2022 |
| Balmore House Management Limited | Households | 1991 |
| Balmore Lodge Woodland Management Company Limited | Households | 1994 |
| Balmore Management Company Limited | Households | 1993 |
| Balmore Park Management Services Limited | Real estate | 1994 |
| Balmore Views Ltd | Real estate | 2019 |
| Balnacraig Property Solutions Ltd | Real estate | 2023 |
| Baloacare Limited | Health & social care | 2026 |
| Balsab Ltd | Hospitality | 2010 |
| Balus Ltd | Wholesale & retail | 2025 |
| Balush Transport Limited | Transport & logistics | 2023 |