| Bleak Hill Limited | Agriculture & fishing | 2019 |
| Blencowe Scaffolding Limited | Construction | 1992 |
| Blissfield Gardens (Chipping Norton) Management Company Limited | Households | 2005 |
| Blissful Cleaning Services Ltd | Administrative & support | 2022 |
| Block 42 IP Ltd | Administrative & support | 2026 |
| Block E Regis Park (Sefter Road) Management Company Limited | Households | 2025 |
| Block Records Ltd | Arts & recreation | 2023 |
| Blocks B-F Colindale Management Company Limited | Households | 2015 |
| Bloom & Roar Ltd | Wholesale & retail | 2026 |
| Blossom Hillfarm (Henham) Residents Management Company Limited | Households | 2015 |
| Blossom Meadow Residents Management Company Limited | Households | 2014 |
| Blue Bay Apartments Limited | Households | 2003 |
| Blue Dog IT Services Limited | Information & communication | 2008 |
| Blue Edge Limited | Information & communication | 2001 |
| Blue Edge Productions Limited | Information & communication | 2000 |
| Blue Edge Publishing Limited | Information & communication | 1998 |
| Blue Frontier IT Ltd | Information & communication | 2005 |
| Blue Frontier Limited | Information & communication | 2002 |
| Blue Lane Holdings Ltd | Information & communication | 2019 |
| Blue Orange Creative Limited | Wholesale & retail | 2009 |
| Blue Square Lake Windermere Limited | Real estate | 2011 |
| Blue Steel Solutions Ltd | Information & communication | 2001 |
| Blue Tech Research Limited | Professional & scientific | 2017 |
| Blue Tech Ventures Limited | Professional & scientific | 2013 |
| Bluebell Meadow (Pebworth) Management Company Limited | Households | 2013 |
| Bluebells (Witham) Management Company Limited | Households | 2019 |
| Blueberry DEN Ltd | Wholesale & retail | 2024 |
| Bluebird Electrical Contractors Ltd | Construction | 2025 |
| Bluejay Acquisitions Limited | Real estate | 2025 |
| Bluepools Ltd | Construction | 2009 |
| Bluerock Sports & Entertainment Limited | Professional & scientific | 2016 |
| Bluestone Aviation Limited | Manufacturing | 2025 |
| Bluestone Centre (Solstice Park) Ltd | Households | 2017 |
| Bluestone Engineering Limited | Professional & scientific | 2020 |
| Bluestone Hydrotherapy Ltd | Other services | 2024 |
| Bluestone Windows & Plastics Ltd | Wholesale & retail | 2019 |
| BLW Clarke Consultancy Limited | Professional & scientific | 2016 |
| BML Care Limited | Health & social care | 2022 |
| BMR Motor's Ltd | Wholesale & retail | 2009 |
| BMT Consulting Services Limited | Extraterritorial | 2016 |
| BO Wild Ltd | Financial services | 2024 |
| Boathouse Meadow Management Limited | Real estate | 1989 |
| Boatwrights Estate Agents Ltd | Real estate | 2015 |
| Bobs Ices Limited | Hospitality | 2022 |
| Boddington & Royall Limited | Wholesale & retail | 2017 |
| Boden Ford Developments Ltd | Construction | 2024 |
| Bodman Livestock Limited | Agriculture & fishing | 2024 |
| Bodo Freight Ltd | Transport & logistics | 2020 |
| Bodyscan Ltd | Other services | 2013 |
| Bodytech Restoration Limited | Administrative & support | 2014 |
| Bodytech Vehicle Repair Specialists Ltd | Wholesale & retail | 2002 |
| Bodywise Pilates Limited | Health & social care | 2010 |
| Bodywise Pilates Teacher Training Ltd | Education | 2014 |
| Bodyworks Fitness Studio Limited | Arts & recreation | 2011 |
| Bodyworks Toning Table Studio Limited | Arts & recreation | 2011 |
| Boldhurst Properties Limited | Real estate | 1986 |
| Boleyn Management Limited | Households | 2012 |
| Bollo Bridge Management Company Limited | Households | 1983 |
| Bolsius (UK) Limited | Wholesale & retail | 1984 |
| Bolt Productions Ltd | Information & communication | 2026 |
| Bolton Bite Ltd | Health & social care | 2021 |
| Bolton Brite Ltd | Health & social care | 2019 |
| Bond Dental Clinic Ltd | Health & social care | 2020 |
| Bond Dentistry Limited | Financial services | 2020 |
| Bondavia Holdings Limited | Financial services | 2022 |
| Bongo Site Services Ltd | Construction | 2023 |
| Boogaloo 1 Limited | Health & social care | 2025 |
| Book in a Box Ltd | Wholesale & retail | 2020 |
| Book Your Lifestyle Limited | Professional & scientific | 2015 |
| Bookmarc Ltd | Information & communication | 2014 |
| Books Illustrated Limited | Professional & scientific | 2010 |
| Boomerang Holdings Ltd | Arts & recreation | 2009 |
| Borders Park Raunds Management Company Limited | Households | 2015 |
| Bordon Phase 3 Management Company Limited | Households | 2024 |
| Borealis Club Ltd | Other services | 2023 |
| Boreham Mead (Facilities Management) Limited | Households | 2021 |
| Bornea (UK) Limited | Professional & scientific | 2023 |
| Bosco London Limited | Manufacturing | 2015 |
| Boscombe Centre Management Company Limited | Real estate | 2001 |
| Boscombe Down Aviation Collection Limited | Arts & recreation | 2007 |
| Boston Antiques Limited | Wholesale & retail | 2020 |
| Boswell Bros.(Salisbury)Limited | Water & waste | 1942 |
| Botleys Farm Ltd | Agriculture & fishing | 2024 |
| Boulder (UK) LLP | | 2014 |
| Bounce Back Health Limited | Health & social care | 2015 |
| Bourne Air Limited | Manufacturing | 2000 |
| Bourne Collyer Limited | Real estate | 2023 |
| Bourne Residents Company Limited | Other services | 1980 |
| Bourne Valley ( Wilts ) Developments Limited | Other services | 2014 |
| Bourne Valley Construction Services Limited | Construction | 2012 |
| Bourne VP Limited | Agriculture & fishing | 2013 |
| Bouverie Avenue Management Limited | Households | 2006 |
| BOW Engineering Limited | Professional & scientific | 2022 |
| BOW Trinity (B) Management Limited | Households | 2011 |
| BOW Trinity (E) Management Limited | Households | 2011 |
| Bowden Joinery Ltd | Manufacturing | 2016 |
| Bower Place Management Company Limited | Households | 2018 |
| Bowerchalke Barn Ltd | Administrative & support | 2019 |
| Bowman Trustees (NO 1) Limited | Extraterritorial | 2015 |
| Bowman Trustees (NO 2) Limited | Extraterritorial | 2015 |