| Baxter Technical Limited | Administrative & support | 2024 |
| Baxterstorey Limited | Hospitality | 1985 |
| Bay Holiday Investments Ltd | Hospitality | 2021 |
| Bay Valley Limited | Other services | 2024 |
| Bay's Peri Peri Limited | Hospitality | 2017 |
| Bayanlade Limited | Professional & scientific | 2012 |
| Baydrift Systems Limited | Information & communication | 1989 |
| Bayer AEH Limited | Professional & scientific | 1965 |
| Bayer Cropscience Limited | Wholesale & retail | 1927 |
| Bayer Public Limited Company | Wholesale & retail | 1968 |
| Bayfield Energy Limited | Professional & scientific | 2007 |
| Bayland Global Limited | Professional & scientific | 2010 |
| Bayland Holdings Limited | Real estate | 2018 |
| Baynexa UK Limited | Wholesale & retail | 2025 |
| Baypony Consulting Solutions Ltd | Professional & scientific | 2017 |
| Bayridge Commercial Property Limited | Real estate | 2026 |
| Bayridge Property Limited | Real estate | 2017 |
| Baytree Logistics Developments Limited | Real estate | 2022 |
| Bazaarvoice Limited | Information & communication | 2006 |
| BB Construct Ltd | Construction | 2025 |
| BB Theatre Productions Ltd | Arts & recreation | 2015 |
| BB Trading Ltd | Arts & recreation | 2023 |
| BB Tumble Tots LLP | | 2024 |
| BBB Sports Limited | Arts & recreation | 2000 |
| Bbbhl Holdings Limited | Other services | 2017 |
| Bbbrotherbuilding Ltd | Construction | 2026 |
| BBK Enterprises Ltd | Other services | 2024 |
| BBM Auto Repairs Ltd | Wholesale & retail | 2019 |
| BBM Group Limited | Manufacturing | 2015 |
| Bbmr Limited | Transport & logistics | 2022 |
| Bbq'D & Braai'D Limited | Hospitality | 2025 |
| Bbsai EDU Limited | Wholesale & retail | 2024 |
| Bbsai Properties Limited | Real estate | 2024 |
| BC Details Limited | Wholesale & retail | 2022 |
| Bcas Bio-Medical Services Limited | Professional & scientific | 2005 |
| BCC Trans Ltd | Transport & logistics | 2018 |
| BCK Education Ltd | Education | 2023 |
| BCK Motorcycles Ltd | Education | 2019 |
| BCL Timber Projects Limited | Construction | 1974 |
| Bcmr Services Ltd | Construction | 2014 |
| BCS Reading Ltd | Transport & logistics | 2019 |
| Bcshh Limited | Health & social care | 2018 |
| BD Development Solutions Ltd | Construction | 2018 |
| BD Web Solutions Limited | Information & communication | 2021 |
| BDA Overseas Limited | Transport & logistics | 1986 |
| Bdeshbc Ltd | Hospitality | 2023 |
| BDS Consultants Ltd | Administrative & support | 2017 |
| BDS Developments Ltd | Construction | 2016 |
| BDS Finance Ltd | Financial services | 2017 |
| BDS Prime Constructions Ltd | Construction | 2026 |
| BDS Surveyors Limited | Professional & scientific | 2007 |
| BDT Transport & Warehousing Ltd | Real estate | 2009 |
| BDT Transport Ltd | Transport & logistics | 2009 |
| BDW Property Investment Limited | Real estate | 2022 |
| BE Creative Solutions Limited | Construction | 2019 |
| BE Presentable Ltd | Information & communication | 2026 |
| BE Tender & Kind Limited | Health & social care | 2023 |
| BE Tender Limited | Health & social care | 2023 |
| BE Your Level 10 Limited | Wholesale & retail | 2022 |
| Be-Dazzled Cleaning Company Limited | Administrative & support | 2019 |
| BEA Ventures Limited | Wholesale & retail | 2024 |
| Beachampton Solar Project Holdco Limited | Energy | 2026 |
| Beachampton Solar Project Limited | Energy | 2019 |
| Beacon Court Management Company (Reading) Limited | Households | 1977 |
| Beacon International Trading Limited | Wholesale & retail | 2022 |
| Beacon Logistics UK Limited | Wholesale & retail | 2011 |
| Beaconsfield Carpets and Flooring Limited | Wholesale & retail | 2012 |
| Beacrow Limited | Professional & scientific | 2020 |
| Beacrow Ventures Limited | Real estate | 2025 |
| Beaded Golden Crown Limited | Professional & scientific | 2015 |
| Beadle & Crome (Reading) Limited | Wholesale & retail | 1972 |
| Beahon Limited | Professional & scientific | 2016 |
| Beale Park Trading Company Limited | Wholesale & retail | 2015 |
| Beales Scaffolding Ltd | Construction | 2007 |
| Beam Properties Limited | Real estate | 2016 |
| Beamgrid Technologies Ltd | Professional & scientific | 2024 |
| Beamm Limited | Administrative & support | 2021 |
| Beamx Ltd | Construction | 2025 |
| Beancounter Solutions UK Limited | Professional & scientific | 2009 |
| Beans & Cream Limited | Hospitality | 2016 |
| Beans Factory Limited | Professional & scientific | 2024 |
| Bear ASH Development Limited | Construction | 2009 |
| Bearing Maintenance Service Limited | Manufacturing | 2007 |
| Bearman Properties Limited | Real estate | 2022 |
| Bearwood College Trustees | Education | 1981 |
| Beau Properties Limited | Construction | 2004 |
| Beauchamp Property Investment Ltd | Real estate | 2025 |
| Beaufort Consultancy Limited | Professional & scientific | 2024 |
| Beaufort Gardens Management Company Limited | Households | 1997 |
| Beaumont-Thomas Ltd | Information & communication | 2015 |
| Beautiful Creatures Theatre | Education | 2017 |
| Beautiful Escape Limited | Other services | 2013 |
| Beautiful Hair by Anna Ltd | Other services | 2025 |
| Beautiful Pillars International Ministry | Other services | 2023 |
| Beautiful Women Ventures Limited | Professional & scientific | 2014 |
| Beauty Mahal Ltd | Other services | 2012 |
| Beauty of the Orient Limited | Other services | 2013 |
| Beauty Salon Monika Ltd | Other services | 2009 |
| Beauté D'Or Ltd | Other services | 2020 |
| Beauté Healthcare Limited | Health & social care | 2024 |