| Biedronka (PL) Ltd | Wholesale & retail | 2014 |
| Bifa Logistics Ltd | Transport & logistics | 2016 |
| Big G Properties Limited | Real estate | 2024 |
| Big Guns Ltd | Wholesale & retail | 2020 |
| Big Heart CIC | Other services | 2025 |
| Big Site Limited | Real estate | 2015 |
| Bigkong Construction Limited | Construction | 2025 |
| Bijoux Events Limited | Administrative & support | 2023 |
| Billingham Builders Ltd | Construction | 2023 |
| Billingsley House Management Company Limited | Households | 2017 |
| Biodeo Ltd | Other services | 2020 |
| Biog-Uk Ltd | Energy | 2010 |
| Birchfield Harriers Investments Limited | Administrative & support | 1984 |
| Birchmeadow Ltd | Real estate | 2016 |
| Birmingham Relocation Services Ltd | Other services | 2021 |
| Bischof & Klein (UK) Limited | Manufacturing | 1978 |
| Bison Fitness Limited | Wholesale & retail | 2018 |
| Bitumen Marketing Limited | Wholesale & retail | 2013 |
| BJB Groundworks Limited | Construction | 2022 |
| BJM Infection Control Ltd | Wholesale & retail | 2020 |
| Bjsells Ltd | Wholesale & retail | 2024 |
| BKR Productions Ltd | Information & communication | 2026 |
| BL Telford Limited | Professional & scientific | 1918 |
| Blac Square Holiday Lettings Limited | Real estate | 2025 |
| Blac Square Limited | Financial services | 2025 |
| Blac Square Management Limited | Real estate | 2025 |
| Black Belt Academy Grading Ltd | Arts & recreation | 2019 |
| Black Craft Limited | Wholesale & retail | 2025 |
| Blackburn Estates Limited | Hospitality | 2013 |
| Blackpool Hotel Developments Ltd | Construction | 2024 |
| Blackpool Hotel Management Ltd | Real estate | 2025 |
| Blackwell Property Investments Ltd | Construction | 2026 |
| Blakeway Ltd | Other services | 2014 |
| Blaugrana Limited | Transport & logistics | 2021 |
| Blazingbanana Limited | Information & communication | 2023 |
| Bleazard and Galletta LLP | | 2004 |
| Blessings Properties Ltd | Real estate | 2022 |
| Blighty Commercial Property Ltd | Real estate | 2014 |
| Blighty Ltd | Real estate | 2005 |
| Blinds 4 Less (UK) Ltd | Wholesale & retail | 2011 |
| BLINDS4LESS - London Limited | Wholesale & retail | 2014 |
| BLINDS4LESS Limited | Wholesale & retail | 2012 |
| BLK Cat Media Ltd | Information & communication | 2024 |
| Block Fencing Contractors Ltd | Construction | 2017 |
| Bloody Good Brews Limited | Hospitality | 2018 |
| Bloom & Build Ltd | Wholesale & retail | 2025 |
| Bloom and Blush Creations PVT. Ltd. | Manufacturing | 2024 |
| Bloombelle Limited | Manufacturing | 2012 |
| Bloompot Limited | Information & communication | 2023 |
| Blue Circle Trans Ltd | Transport & logistics | 2018 |
| Blue County Limited | Other services | 2017 |
| Blue Elephant Indian Cuisine Limited | Hospitality | 2021 |
| Blue Elephant Indian Restaurant Limited | Hospitality | 2020 |
| Blue Halo Enterprises Ltd | Manufacturing | 2023 |
| Blue IVY Limited | Real estate | 2017 |
| Blue Maleo Ltd | Other services | 2014 |
| Blue Renovations Ltd | Real estate | 2025 |
| Blue Turtle Physiotherapy & Wellness Clinic Ltd | Health & social care | 2024 |
| Blueberry Assets Ltd | Real estate | 2024 |
| Bluehub Finance Consultants Ltd | Professional & scientific | 2024 |
| Bluehub Group Limited | Financial services | 2025 |
| Bluehub IT Consultants Ltd | Information & communication | 2012 |
| Bluerock Industries Limited | Construction | 2024 |
| Bluestone Civils Ltd | Construction | 2025 |
| Bluetech IT Services Ltd | Information & communication | 2024 |
| Blugen Ltd | Other services | 2019 |
| Blutech Limited | Wholesale & retail | 2025 |
| Blutri Ltd | Other services | 2019 |
| BMI Prime Ltd | Transport & logistics | 2026 |
| BMS Cyber Defence Ltd | Information & communication | 2023 |
| Bnhv Properties Ltd | Real estate | 2021 |
| BNR Computer Services Limited | Wholesale & retail | 2007 |
| Boadu Legal Services Ltd | Professional & scientific | 2026 |
| Bod's Properties Limited | Information & communication | 2018 |
| Bodum (U.K.) Limited | Wholesale & retail | 1984 |
| Body & Mind Skin Care Centre Limited | Other services | 2014 |
| Body Firm Clinic Ltd | Other services | 2019 |
| Bohomoon Ltd | Wholesale & retail | 2014 |
| Bokangphoka Ltd | Health & social care | 2023 |
| Bol.Brothers Limited | Real estate | 2026 |
| Bold Investment Group Ltd | Real estate | 2024 |
| Boldstreet Freehouse Ltd | Real estate | 2025 |
| Bollpoint Hand Car Wash Ltd | Administrative & support | 2025 |
| Bollstans Ltd | Other services | 2019 |
| Bolt King Ltd. | Manufacturing | 2015 |
| Bolton Granite Ltd | Manufacturing | 2025 |
| BOM Systems Ltd | Professional & scientific | 2006 |
| Bond Property Rentals Ltd | Hospitality | 2026 |
| Bondex Ltd | Transport & logistics | 2019 |
| Borari Ltd | Other services | 2020 |
| Borland Roadliner Ltd | Transport & logistics | 2018 |
| Bormeo Ltd | Other services | 2022 |
| Born 91 Ltd | Wholesale & retail | 2021 |
| Borne Digital Limited | Information & communication | 2014 |
| Boss Club Limited | Other services | 2025 |
| Boss Systems Ltd | Information & communication | 2015 |
| Bostin Design Services Ltd | Professional & scientific | 2016 |
| Bostmont Ltd | Other services | 2020 |
| Botafago Ltd | Other services | 2019 |
| Botosani Ltd | Other services | 2020 |