| Axeus Residential Cardiff Limited | Real estate | 2016 |
| Axeus Residential Croydon Limited | Extraterritorial | 2016 |
| Axeus Residential Limited | Extraterritorial | 2016 |
| Axis Supplements Limited | Wholesale & retail | 2026 |
| Ayrmer Software Limited | Information & communication | 2008 |
| Ayse Ltd | Other services | 2026 |
| Azrama Homes Ltd | Hospitality | 2025 |
| AZZ Construction Ltd | Administrative & support | 2017 |
| B & C Property Engineers Ltd | Construction | 2015 |
| B & M Engineers Limited | Manufacturing | 2007 |
| B G Reinforcements Limited | Construction | 2017 |
| B J H Attiwell Ltd | Transport & logistics | 2020 |
| B Lundy Consulting Limited | Professional & scientific | 2026 |
| B&M Packaging Services Limited | Manufacturing | 2011 |
| B-Elite Limited | Wholesale & retail | 2023 |
| B-Elite Performance Ltd | Education | 2026 |
| B-Haul Limited | Transport & logistics | 2017 |
| B. Jacks Groundworks Co. Group Limited | Construction | 2020 |
| B. Jacks Groundworks Limited | Construction | 2000 |
| B.H. White & SON Limited | Manufacturing | 2008 |
| Babyjays Ltd | Administrative & support | 2026 |
| Back Developments (SW) Limited | Construction | 2023 |
| Backer International Limited | Hospitality | 2025 |
| BAD BOY Burgers Ltd | Hospitality | 2020 |
| BAD BOY Burgers Mobile Ltd | Hospitality | 2021 |
| Baffins Farm Catering Limited | Hospitality | 2022 |
| Bags of Help Collections Ltd | Other services | 2012 |
| Bahoz Ltd | Hospitality | 2025 |
| Baileys & Co.(Blackpool) Ltd | Hospitality | 2022 |
| Baker's Maintenance Ltd | Administrative & support | 2018 |
| Balanced Energy Ltd | Professional & scientific | 2020 |
| Baltag Express Ltd | Transport & logistics | 2025 |
| Baltic Pine Limited | Wholesale & retail | 2011 |
| Baltika Supermarket Ltd | Wholesale & retail | 2024 |
| Barford Park Racing Limited | Real estate | 2008 |
| Barns Vertigo Limited | Other services | 2021 |
| BARRT1 Ltd | Real estate | 2023 |
| Barton Property Developers Ltd | Extraterritorial | 2020 |
| Base Structures Group Limited | Other services | 2018 |
| Base Structures Ltd | Manufacturing | 2019 |
| Base Structures UK Ltd | Construction | 2012 |
| BAT Fuel & Shop Ltd | Wholesale & retail | 2018 |
| Bates Print Engineering Ltd | Manufacturing | 2002 |
| Bath Bridge Business Park Management Company Limited | Professional & scientific | 2006 |
| Bath Imaging Partners LLP | | 2005 |
| Batmink Property Holdings Ltd | Financial services | 2025 |
| Bay Air Conditioning & Refrigeration Ltd | Construction | 2011 |
| Bayford Systems Limited | Extraterritorial | 2013 |
| Bazalogix Ltd | Transport & logistics | 2024 |
| BBX Trading Limited | Wholesale & retail | 2024 |
| BC Contracting Ltd | Information & communication | 2026 |
| BCL Groundworks Limited | Construction | 2009 |
| BCL Group Holdings Ltd | Financial services | 2025 |
| BCL Holdings (South West) Ltd | Financial services | 2021 |
| BD Procurement Services Limited | Information & communication | 2015 |
| BE Climate Ready Ltd | Wholesale & retail | 2024 |
| Beachwood RTB Ltd | Real estate | 2021 |
| Beale Heating & Building Limited | Construction | 2002 |
| Beals Wheels Limited | Education | 2013 |
| Bear and Bailey Properties Ltd | Real estate | 2020 |
| Bear's Garage Ltd | Wholesale & retail | 2023 |
| Beardsproperty Ltd | Real estate | 2024 |
| Beatrunner Limited | Information & communication | 2019 |
| Beauforte Enterprises Limited | Real estate | 2001 |
| BEC Flox Limited | Construction | 2025 |
| Becoming Rare LLP | | 2025 |
| Bedminster Barbers Limited | Other services | 2025 |
| Bedrock Furniture (Somerset) Limited | Wholesale & retail | 2018 |
| Beijing 665 Limited | Hospitality | 2024 |
| Benjamin Grant Investments Limited | Professional & scientific | 2025 |
| Benvardin Equine Limited | Agriculture & fishing | 2020 |
| Bepe Group Holdings Limited | Financial services | 2025 |
| Berkeley Chess Ltd | Wholesale & retail | 2017 |
| Berkeley Vale Homes (W) Ltd | Construction | 2021 |
| Betcher Transport Ltd | Transport & logistics | 2013 |
| Beyond the Facade Limited | Professional & scientific | 2016 |
| BFF Nonwovens Limited | Manufacturing | 2002 |
| BHW Scaffolding Ltd | Construction | 2024 |
| Big Green Hill Productions Ltd | Information & communication | 2025 |
| Bigdisk Limited | Information & communication | 1994 |
| Bike-Seal Ltd | Wholesale & retail | 2015 |
| Billy's Cars Ltd | Wholesale & retail | 2025 |
| Biotek Limited | Professional & scientific | 1999 |
| Bishops Buildings Services Limited | Construction | 2018 |
| Biss Events Ltd | Administrative & support | 2023 |
| Bitten by Wolf Ltd | Information & communication | 2018 |
| BJD Plumbing Limited | Construction | 2025 |
| BK Process Solutions Ltd | Professional & scientific | 2020 |
| Black and White Projects Ltd | Administrative & support | 2019 |
| Black Cat Consultants Ltd | Professional & scientific | 2022 |
| Black HAT Training Ltd | Administrative & support | 2017 |
| Black Oak Solutions Ltd | Manufacturing | 2022 |
| Black Raven Design Limited | Administrative & support | 2016 |
| Blackandwhiteandread Ltd | Wholesale & retail | 2017 |
| Blackmore Eagle & Lewis (Properties) Limited | Real estate | 1997 |
| Blackstar Interactive Ltd | Information & communication | 2026 |
| Blackthorn Computer Consultancy Limited | Information & communication | 1997 |
| Blaenau Gwent Energy Limited | Professional & scientific | 2018 |
| Blake Development Ltd | Arts & recreation | 2024 |
| Blake Hall Bridgwater Limited | Hospitality | 2024 |