| Bhdent Holding Limited | Financial services | 2019 |
| Bhdent Property Limited | Real estate | 2019 |
| BHF 1990 Ltd | Construction | 2026 |
| Bible by the Beach | Other services | 2008 |
| Bibs Bar Limited | Hospitality | 2018 |
| BID UP Ltd | Administrative & support | 2000 |
| Bidurk Ltd | Professional & scientific | 2020 |
| Big Bean Construction Ltd | Construction | 2011 |
| Big BEN English Ltd | Education | 2026 |
| Bighat Digital Ltd | Information & communication | 2018 |
| Bigspin Media Limited | Professional & scientific | 2010 |
| Bigweb Multimedia Limited | Information & communication | 2005 |
| Bihu (UK) Limited | Professional & scientific | 2001 |
| Biig Luxe Limited | Manufacturing | 2025 |
| Bilbury Mews Eastbourne Limited | Households | 1993 |
| Bill Door Limited | Professional & scientific | 2016 |
| Biognosis Limited | Other services | 1997 |
| Bionic Digital Solutions Limited | Professional & scientific | 2023 |
| Bira Corporation Limited | Information & communication | 2018 |
| Birch Management Estates Ltd | Administrative & support | 2017 |
| Birchwood Motor Group Limited | Wholesale & retail | 2008 |
| Birchwood Trading Limited | Real estate | 2008 |
| Birdhouse Audio Limited | Information & communication | 2025 |
| Birling Property Services Sussex Ltd | Construction | 2022 |
| Bishak Construction Ltd | Construction | 2026 |
| Bishop & Levett Limited | Construction | 2003 |
| Bishop Capital Limited | Financial services | 2023 |
| Bishops Meadow Park OP Limited | Professional & scientific | 2024 |
| Bishops Meadow Park Opsh Limited | Professional & scientific | 2024 |
| Bitflow Investments 427 Limited | Extraterritorial | 2015 |
| Bitter Rivals Ltd | Wholesale & retail | 2024 |
| Bizmagnet Ltd | Professional & scientific | 2025 |
| BKN Building Services Limited | Construction | 2019 |
| Black & White Stripes Holdings Limited | Financial services | 2021 |
| Black Cat White Cat Ltd | Professional & scientific | 2009 |
| Black Country Anaesthetic Services Ltd | Health & social care | 2017 |
| Black Star Productions Limited | Information & communication | 2017 |
| Blackbirdbox Consultancy Ltd | Manufacturing | 2026 |
| Blackline MOT Ltd | Professional & scientific | 2026 |
| Blackstone National Carriers Limited | Transport & logistics | 2018 |
| Blackstone Securities Limited | Construction | 2011 |
| Blackstones Consulting Limited | Professional & scientific | 2009 |
| Blackwater Lodge Properties Limited | Households | 1998 |
| Blackwater Residents Company Limited | Real estate | 2002 |
| Blackwaterfoot Advisory Ltd | Professional & scientific | 2021 |
| Blake Hampton Ltd | Wholesale & retail | 2025 |
| Blakes Contracting Limited | Construction | 2012 |
| Blink Tank Limited | Information & communication | 2010 |
| Blink.Uk.Net Limited | Construction | 2002 |
| Blissful Living Property Ltd | Construction | 2024 |
| Block 3 Martello Quay Residents Company Limited | Households | 2003 |
| Block 4 Martello Quay Residents Company Limited | Real estate | 2003 |
| Block 4 Rushlake Limited | Households | 2008 |
| Block Party Event Management Ltd | Arts & recreation | 2022 |
| Blood Specialist Ltd | Health & social care | 2014 |
| Bloom Inc. Limited | Administrative & support | 2025 |
| Blossom Mill Close Limited | Households | 2025 |
| Blow by Blow Limited | Information & communication | 2010 |
| Blue Bar Cafe Limited | Hospitality | 2005 |
| Blue Box Selfstore Limited | Transport & logistics | 2016 |
| Blue Cauldron Ltd | Extraterritorial | 2003 |
| Blue Crab Company Worldwide Ltd | Extraterritorial | 2020 |
| Blue Crane Limited | Information & communication | 2013 |
| Blue Fina Ltd | Professional & scientific | 2021 |
| Blue Horizon Attractions Ltd | Information & communication | 2021 |
| Blue Light Fisheries Limited | Agriculture & fishing | 2024 |
| Blue Orchid 44 Limited | Wholesale & retail | 2017 |
| Blue Planet Trading Ltd | Wholesale & retail | 2020 |
| Blue Saphire Ltd | Hospitality | 2022 |
| Blue SAPHIRE1 Ltd | Hospitality | 2023 |
| Blue Sea Fish Bar Limited | Hospitality | 2025 |
| Blue Seagulls Ltd | Professional & scientific | 2020 |
| Blue Wolf Team Building Ltd | Education | 2022 |
| Bluebeach Management Limited | Administrative & support | 2011 |
| Blueprint Steel Ltd | Administrative & support | 2015 |
| Blueprint Structures Ltd | Construction | 2018 |
| Blueriver Investments (George Lane) Limited | Real estate | 2020 |
| Blueriver Investments Ltd | Real estate | 2013 |
| Bluestone Hardware Solutions Limited | Professional & scientific | 2022 |
| Blueview Capital Limited | Information & communication | 2014 |
| Bluey Pink Limited | Professional & scientific | 2019 |
| Blune Limited | Information & communication | 2026 |
| BM Cars Sussex Ltd | Wholesale & retail | 2017 |
| Bodiblossom Ltd | Arts & recreation | 2023 |
| Bold London Ltd | Administrative & support | 2013 |
| Bolo Solutions Ltd | Wholesale & retail | 2019 |
| Bolton Road Ltd | Hospitality | 2017 |
| Bonji's Ltd | Hospitality | 2021 |
| Bonnington Bloomsbury Limited | Administrative & support | 2006 |
| Bonnington Group Limited | Financial services | 1999 |
| Bonnington Hotels Limited | Extraterritorial | 1909 |
| Bonnington Investments and Developments Limited | Extraterritorial | 2004 |
| Bonnington Syon Lane Limited | Real estate | 2006 |
| Bonzer Data Solutions Ltd | Information & communication | 2020 |
| Book Protectors & Co. Limited | Manufacturing | 1969 |
| Booster Consulting Ltd | Professional & scientific | 2019 |
| Boothman Holdings Ltd | Financial services | 2024 |
| Boredom Kills Creative Ltd | Professional & scientific | 2020 |
| Borne Project Services Ltd | Professional & scientific | 2020 |
| Borrett Ltd | Construction | 2021 |