| BAS Dermatology Limited | Health & social care | 2016 |
| BAS Midlands Ltd | Wholesale & retail | 2023 |
| Basahanvi Travel Ltd | Transport & logistics | 2025 |
| Basant Ltd | Real estate | 2023 |
| Base Impact Support Ltd | Administrative & support | 2019 |
| Base Ltd | Health & social care | 2019 |
| Base Mountain Construction Ltd | Manufacturing | 2026 |
| Base Performance Ltd | Arts & recreation | 2025 |
| Base Support Limited | Administrative & support | 2022 |
| Base Women's Housing CIC | Other services | 2015 |
| Basecomms Ltd | Other services | 2018 |
| Basel Trading Ltd | Wholesale & retail | 2023 |
| Baseline Studio Ltd | Manufacturing | 2026 |
| Baseline Support Ltd | Administrative & support | 2025 |
| Basemoor Limited | Construction | 2008 |
| BASH2314 Limited | Hospitality | 2025 |
| BASH5 Holdings Ltd | Real estate | 2021 |
| Bashad Healthcare Solutions (BHS) Limited | Health & social care | 2020 |
| Bashert Films Ltd | Information & communication | 2023 |
| Bashir & Co Ltd | Professional & scientific | 2016 |
| Bashir Associates Limited | Professional & scientific | 2002 |
| Bashir Kassam Associates Ltd | Administrative & support | 2016 |
| Bashir Legal Ltd | Professional & scientific | 2022 |
| Bashir&Ghous Limited | Wholesale & retail | 2024 |
| Bashsolutions Ltd | Transport & logistics | 2026 |
| Basi & Co Investments Ltd | Real estate | 2020 |
| Basicaction Limited | Information & communication | 1995 |
| Basil & Bonnet Ltd | Manufacturing | 2020 |
| Basil Trading Ltd | Wholesale & retail | 2026 |
| Basile Limited | Construction | 2018 |
| Basit ALI Ltd | Wholesale & retail | 2024 |
| Basith Limited | Real estate | 2008 |
| Basix Cosmetics Trading UK Ltd | Wholesale & retail | 2022 |
| Basket a Bargain Ltd | Wholesale & retail | 2024 |
| Basket Digital Limited | Wholesale & retail | 2018 |
| Basket Grabs Limited | Wholesale & retail | 2025 |
| Baslic Limited | Transport & logistics | 2018 |
| Baslow Close 1965 Limited | Extraterritorial | 2014 |
| Basma Emaar Limited | Administrative & support | 2022 |
| Basma International Ltd | Transport & logistics | 2025 |
| Basmah Parcels Ltd | Transport & logistics | 2024 |
| Basmala Properties Limited | Hospitality | 2025 |
| Basmati Lounge Ltd | Hospitality | 2019 |
| Basran Limited | Wholesale & retail | 2018 |
| Bass Barn Creative CIC | Information & communication | 2026 |
| Bass Barn Ltd | Information & communication | 2024 |
| Bass House Limited | Administrative & support | 2008 |
| Bassai Limited | Health & social care | 2018 |
| Bassan Supplies Limited | Wholesale & retail | 2007 |
| Bassi Capital Limited | Other services | 2018 |
| Bassi Construction Ltd | Construction | 2026 |
| Bassi Investments Ltd | Real estate | 2022 |
| Bassi Solicitors Limited | Professional & scientific | 2011 |
| Bassies Kitchen Ltd | Manufacturing | 2024 |
| Bassline Property Holdings Limited | Financial services | 2019 |
| Bassra Machine Tools Limited | Manufacturing | 1997 |
| Bastable Ltd | Professional & scientific | 2018 |
| Bastable Property Ltd | Real estate | 2022 |
| Bastan Ltd | Professional & scientific | 2022 |
| Bastet Lettings Ltd | Hospitality | 2017 |
| Bastion Equity Limited | Professional & scientific | 1980 |
| Basudev Enterprise Ltd | Health & social care | 2010 |
| Basudev Limited | Financial services | 2023 |
| Batasi Limited | Extraterritorial | 2012 |
| Batcha Clothing Ltd | Wholesale & retail | 2023 |
| Batchelor Estates Limited | Real estate | 2012 |
| Batchelor Polyurethanes Limited | Manufacturing | 1997 |
| Batchelor Resources Limited | Manufacturing | 2025 |
| Batchline Transport Solutions Ltd | Transport & logistics | 2025 |
| Bateman Catering Organization Limited(The) | Professional & scientific | 1950 |
| Bateman Extraction Services Ltd | Construction | 2017 |
| Bates Construction Management Limited | Professional & scientific | 2025 |
| Bates Limited | Health & social care | 2013 |
| Bath Cardiac Services Ltd | Health & social care | 2019 |
| Bath Property Corporation Ltd | Real estate | 2025 |
| Bath ROW Bottling Company Ltd | Manufacturing | 2023 |
| Bath Skyline Limited | Information & communication | 2018 |
| Bathex (Bathroom & Accessories) Limited | Manufacturing | 1977 |
| Bathla Properties Limited | Real estate | 2014 |
| Bathroom City Limited | Wholesale & retail | 1995 |
| Bathroom Junction Ltd | Wholesale & retail | 2017 |
| Bathroom Mastery Ltd | Construction | 2024 |
| Baticom Digital Ltd | Information & communication | 2025 |
| Batool Enterprises Limited | Wholesale & retail | 2025 |
| Batool Zaidi Ltd | Administrative & support | 2024 |
| Batrich Developments 02 Ltd | Real estate | 2026 |
| Batrich Developments 03 Ltd | Real estate | 2026 |
| Batrich Developments Ltd | Real estate | 2023 |
| Batrich Group Holdings Ltd | Real estate | 2023 |
| Battals Baklava & Patisserie Limited | Manufacturing | 2010 |
| Battery Shop Sussex Ltd | Wholesale & retail | 2019 |
| Batterybull Charge Ltd | Construction | 2020 |
| Battle Play Limited | Arts & recreation | 2025 |
| Battle Systems Ltd | Arts & recreation | 2013 |
| Battlestreamlive Ltd | Information & communication | 2016 |
| BAU Studio Limited | Other services | 2026 |
| Bauaa Ltd | Real estate | 2019 |
| Baublelicious Limited | Wholesale & retail | 2017 |
| Bauhaus Carpentry & Joinery Ltd | Manufacturing | 2020 |
| Baulogik Limited | Professional & scientific | 2025 |