| Baris Trasures Limited | Health & social care | 2019 |
| Barker Healey Property Limited | Real estate | 2013 |
| Barkwall Joinery Limited | Construction | 2009 |
| Barlow Business Support Ltd | Extraterritorial | 2017 |
| Barmaw Limited | Health & social care | 2022 |
| Barnet in a Barn Ltd. | Other services | 2021 |
| Barneys Cafe Ltd | Hospitality | 2025 |
| Barnmeadow Dog Services Ltd | Other services | 2018 |
| Barnyards Trading Ltd | Hospitality | 2017 |
| Barranco Lima Ltd | Hospitality | 2023 |
| Barratt at Swanbourne Park Management Company Limited | Households | 2015 |
| Barrell Media & Events Limited | Information & communication | 2014 |
| Barrett Thomas Electrical Ltd | Construction | 2025 |
| Barrie Curtis Plastering Ltd | Construction | 2015 |
| Barritt Brothers Limited | Administrative & support | 2015 |
| Bart's Bins Newport Limited | Administrative & support | 2019 |
| Bartletts Building and Roofing Contractors Limited | Construction | 2002 |
| Barton Inc Ltd | Financial services | 2026 |
| Barton Training Limited | Professional & scientific | 2017 |
| Barwick Family Properties Ltd | Real estate | 2025 |
| Basamma ENT Limited | Health & social care | 2020 |
| Base Compliance Ltd | Professional & scientific | 2025 |
| Basetags Ltd | Wholesale & retail | 2024 |
| Basic Store Limited | Wholesale & retail | 2025 |
| Basil Buildings Limited | Real estate | 2023 |
| Basirs Bakery Newport Ltd | Wholesale & retail | 2025 |
| Bass Development Group Limited | Construction | 2018 |
| Bass Management Group Limited | Households | 2018 |
| Bassaleg Homes Limited | Wholesale & retail | 1988 |
| Bassaleg House Consulting Limited | Professional & scientific | 2023 |
| Bassettwood Management Ltd | Real estate | 2019 |
| Bates Urology Limited | Health & social care | 2017 |
| Battered Shack Limited | Hospitality | 2018 |
| Battersea Bridge Investments Limited | Other services | 1997 |
| Battle of the Beasts Ltd | Information & communication | 2025 |
| Battlezone Official Ltd | Information & communication | 2026 |
| Batty-Phillips Holdings Limited | Professional & scientific | 2020 |
| Bauen Property Developments Limited | Real estate | 2020 |
| Baxcrest Limited | Construction | 1986 |
| Bay Travel Limited | Administrative & support | 1969 |
| BAY91 Ltd | Hospitality | 2017 |
| Bayclose Management Limited | Households | 2002 |
| Bayfield Property Ltd | Real estate | 2008 |
| Bayit Keys Limited | Real estate | 2023 |
| Bayleaf Textile Limited | Extraterritorial | 2018 |
| Bayliss Recovery (Holdings) Limited | Financial services | 2015 |
| Bayliss Recovery Limited | Water & waste | 2001 |
| Bayraktar Bookkeeping Ltd | Professional & scientific | 2020 |
| Bayside Beach Limited | Wholesale & retail | 2021 |
| Bayton Ltd | Professional & scientific | 2024 |
| BBB Newport Limited | Real estate | 2024 |
| BBS (Brighstone Building Services) Ltd | Construction | 2020 |
| BBS Barbers Ltd | Other services | 2023 |
| BC Composite & Repairs Ltd | Manufacturing | 2024 |
| BC Wind Repairs Limited | Professional & scientific | 2023 |
| BCE Contracting and Consulting Ltd | Construction | 2026 |
| BCH Commercial Investments Limited | Professional & scientific | 2016 |
| BCL (Holdings) Limited | Financial services | 2013 |
| BCL Productions Ltd | Information & communication | 2025 |
| Bcrlm Ltd | Professional & scientific | 2025 |
| BCS Domestic Cleaning Ltd | Administrative & support | 2020 |
| BD GEO Services Limited | Professional & scientific | 2024 |
| Bdnc Project Management Ltd | Professional & scientific | 2016 |
| BE Avram Transports Limited | Transport & logistics | 2025 |
| BE Bold Media Limited | Professional & scientific | 2007 |
| BE Events Holdings Ltd | Financial services | 2026 |
| BE Expo Limited | Administrative & support | 2020 |
| BE Independent Limited | Financial services | 2004 |
| BE Inspired Aesthetics Ltd | Other services | 2025 |
| BE Joined Ltd | Construction | 2026 |
| BE Kitchens Ltd | Construction | 2024 |
| BE the Light Therapies and Wellbeing CIC | Health & social care | 2026 |
| Beacon Electrical & Instrumentation Ltd | Construction | 2026 |
| Beacon Information Services Limited | Information & communication | 2018 |
| Beacon SLS Ltd | Health & social care | 2016 |
| Beadle House Investments Ltd | Real estate | 2021 |
| Beagle Close 1961 Limited | Extraterritorial | 2014 |
| Beagles 4 Rehoming Limited | Administrative & support | 2018 |
| Beaky Limited | Wholesale & retail | 2009 |
| Beam Sports & Schoolwear Limited | Wholesale & retail | 2018 |
| Bear & Pear Clothing Ltd | Wholesale & retail | 2025 |
| Bear Developments (Cardiff) Ltd | Real estate | 2021 |
| Bear Structures Ltd | Professional & scientific | 2018 |
| Beau Car Parks Ltd | Transport & logistics | 2025 |
| Beau Court Stud and Riding School Limited | Agriculture & fishing | 1972 |
| Beau Marques Limited | Wholesale & retail | 2024 |
| Beaum Vape Limited | Wholesale & retail | 2015 |
| Beaumonde Consulting Limited | Professional & scientific | 2006 |
| Beauty & Bliss Ltd | Other services | 2025 |
| Beauty Box Limited | Other services | 2017 |
| Beauty by Chloe NFS 94 Ltd | Other services | 2024 |
| Beauty by Kalisha Ltd | Other services | 2016 |
| Beauty Smash Ltd | Wholesale & retail | 2024 |
| Beautybyc CYF | Other services | 2025 |
| Beautybyelise Ltd | Wholesale & retail | 2025 |
| Beauté Cosmetics by Aliyah Ltd | Wholesale & retail | 2022 |
| Beckslashes CYF | Other services | 2025 |
| Beckwoods Sports Ltd | Hospitality | 2020 |
| Beds Direct From Sleepers Ltd | Wholesale & retail | 2012 |
| BEE Happy Bakery Ltd | Hospitality | 2019 |