| Bexar County Ltd | Hospitality | 2026 |
| Beyond Behaviour Limited | Education | 2015 |
| BF Darlow Limited | Manufacturing | 2004 |
| BFA Care Services Limited | Health & social care | 2020 |
| BFS Topco Limited | Financial services | 2024 |
| Bfsl Limited | Financial services | 1992 |
| BG Global Trans Ltd | Extraterritorial | 2025 |
| BG Investments (UK) Limited | Professional & scientific | 2004 |
| BG Mini Market Ltd | Wholesale & retail | 2024 |
| BGC Consultancy Limited | Professional & scientific | 2018 |
| BGC Removals Ltd | Transport & logistics | 2025 |
| BGE1 Ltd | Professional & scientific | 2024 |
| BGL (Holdings) Limited | Financial services | 2016 |
| BGL Group Limited | Financial services | 1991 |
| Bgllogistic Ltd | Transport & logistics | 2024 |
| BGM Foods Ltd | Wholesale & retail | 2024 |
| BGN Building Services Ltd | Manufacturing | 2021 |
| BGS2M Ltd | Health & social care | 2018 |
| BH Care and Recruitment Services Ltd | Health & social care | 2023 |
| BHA Consulting Limited | Administrative & support | 2010 |
| BHA Holdings Ltd | Construction | 2017 |
| Bhava Enterprise Limited | Other services | 2018 |
| Bhimani Properties UK Ltd | Real estate | 2025 |
| Bhuku Ltd | Information & communication | 2024 |
| Bhungane Limited | Health & social care | 2014 |
| Bhutta Corporations Ltd | Wholesale & retail | 2025 |
| BI (Top) Services Limited | Extraterritorial | 2017 |
| BI Properties (EA) Ltd | Real estate | 2024 |
| Bianchi Swim Ltd | Wholesale & retail | 2026 |
| Biba Boutique Ltd | Wholesale & retail | 2024 |
| Biba Investments Ltd | Real estate | 2025 |
| Bibby Crystals Limited | Wholesale & retail | 2006 |
| Bibi Cris Ltd | Transport & logistics | 2021 |
| Bible Quiz Quest Ltd | Education | 2025 |
| Bidbury Consulting Limited | Professional & scientific | 2019 |
| Biddle Developments Limited | Real estate | 2001 |
| Bifa Trading Ltd | Wholesale & retail | 2023 |
| Bifolds Canopies and Blinds Limited | Administrative & support | 2019 |
| Big Apple Fresh Fruit Vegetables and Delicate Ltd | Wholesale & retail | 2025 |
| Big Bale Company Limited | Extraterritorial | 2020 |
| Big Bear Hire Ltd | Wholesale & retail | 2015 |
| Big G VAC EX Ltd | Construction | 2019 |
| Big Momo Group Limited | Hospitality | 2026 |
| Big Planet UK Limited | Hospitality | 1998 |
| Big WIN Lottery Ltd | Administrative & support | 2026 |
| Bigboyclean Ltd | Administrative & support | 2020 |
| Bigday Designs Holdings Limited | Financial services | 2018 |
| Bigday Designs T/As Lami Manufacturing Ltd | Manufacturing | 2025 |
| Bigger Education Ltd | Other services | 2025 |
| Bigger Print Ltd | Manufacturing | 2021 |
| Biggin Hill Residents Company Limited | Households | 2005 |
| Bijou Peterborough Limited | Hospitality | 2024 |
| Bikesport News.Com Limited | Information & communication | 2000 |
| Bilal Healthcare Ltd | Health & social care | 2013 |
| Bill & Sons Commercial Properties Ltd | Real estate | 2022 |
| Bill & Sons Property Portfolio Ltd | Real estate | 2019 |
| Billionaire Concierge Ltd | Other services | 2017 |
| Billyblonde Limited | Wholesale & retail | 2020 |
| Bimble Inn (Peterborough) Limited | Hospitality | 2016 |
| Bimetric Limited | Information & communication | 2026 |
| BIN Razzaq Ltd | Wholesale & retail | 2026 |
| Binar Limited | Transport & logistics | 2025 |
| Binas Convenience Limited | Wholesale & retail | 2021 |
| Bingham Carpentry & Formwork Limited | Construction | 2010 |
| Bingham Property Holdings Ltd | Real estate | 2025 |
| Binisha&Benita Limited | Health & social care | 2014 |
| Binya Mien Properties Ltd | Real estate | 2025 |
| BIO Naturals Limited | Wholesale & retail | 2024 |
| Biohack Factory Ltd | Wholesale & retail | 2025 |
| Biosync Solutions Ltd | Information & communication | 2026 |
| BIR Haulage Ltd | Construction | 2017 |
| Birch Vista Ltd | Professional & scientific | 2026 |
| Birchedge Limited | Wholesale & retail | 2025 |
| Birchester Care Holdings Limited | Financial services | 2018 |
| Birchester Care Limited | Health & social care | 2017 |
| Birchester Developments Limited | Construction | 1994 |
| Birchester Limited | Professional & scientific | 1994 |
| Birchfield Springfields Ltd | Real estate | 2024 |
| Bird & Co Ltd | Professional & scientific | 2009 |
| Birdie’S Clothing Ltd | Wholesale & retail | 2025 |
| Birds Nest Limited | Real estate | 2025 |
| Birdview Property Ltd | Households | 2022 |
| Birk Consultancy Services Limited | Professional & scientific | 2018 |
| Birk Real Estate Limited | Real estate | 2023 |
| Birmingham Hijama Centre Ltd | Health & social care | 2014 |
| Bishnu & L Company Limited | Health & social care | 2024 |
| Bishops 4X4 Limited | Wholesale & retail | 2012 |
| Bishops Grange Residents Management Company Limited | Households | 2020 |
| Bishops Green Management Company Limited | Households | 2001 |
| Bishops Walk Barnack Limited | Construction | 2019 |
| Bisl Limited | Administrative & support | 1996 |
| Bismillah Butchers Ltd | Hospitality | 2013 |
| Bismillah Investments (Cambs) Ltd | Real estate | 2012 |
| Bismillah Properties (Cambs) Limited | Administrative & support | 2016 |
| Bison (UK) Limited | Wholesale & retail | 2012 |
| Bistrovas Transportation Limited | Transport & logistics | 2023 |
| Bisu Enterprises Limited | Professional & scientific | 2025 |
| Biswas & Sons Ltd | Wholesale & retail | 2024 |
| Bite HQ Ltd | Hospitality | 2026 |
| Bite Lunch Co Ltd | Hospitality | 2025 |