| Berry Cranes Limited | Construction | 2002 |
| Bespoke Audio Visual Systems Ltd | Construction | 2023 |
| Beyond Networks Limited | Information & communication | 2004 |
| Beyond the Bell Club Ltd | Education | 2026 |
| Beyond the Norm Homecare Ltd | Health & social care | 2026 |
| BFN Accounts & Tax Limited | Professional & scientific | 2017 |
| BG Interiors Limited | Construction | 2013 |
| BGF4 (Eton House) LLP | | 2021 |
| BGF4 (Nominee) Limited | Financial services | 2020 |
| BGF4 (Nottingham) LLP | | 2020 |
| BGF4 (Witham) LLP | | 2020 |
| BGF5 (Bracknell 2) LLP | | 2023 |
| BGF5 (Bristol Aztec) LLP | | 2022 |
| BGF5 (Hardwicke) LLP | | 2025 |
| BGF5 (Nominee) Limited | Financial services | 2022 |
| BGF5 (Self Storage) LLP | | 2025 |
| BGF5 (SS Chester) LLP | | 2024 |
| BGF5 (SS Doncaster) LLP | | 2025 |
| BGF5 (SS Finance 1) LLP | | 2025 |
| BGF5 (SS Lincoln) LLP | | 2024 |
| BGF5 (ST Chads) LLP | | 2025 |
| BGF5 (Stevenage) LLP | | 2025 |
| BGF5 (Whittlesford 1) LLP | | 2024 |
| BGF5 (Whittlesford 1A) LLP | | 2025 |
| BGF5 (Whittlesford 1B) LLP | | 2025 |
| BGF5 (Whittlesford 2) LLP | | 2024 |
| BGF5 (Whittlesford) LLP | | 2024 |
| Bgfv Feeder Ltd | Financial services | 2023 |
| BGN Events Ltd | Information & communication | 2020 |
| Bidwell West (Works) Limited | Construction | 2018 |
| Bidwell West 1 Limited | Real estate | 2018 |
| Bidwell West 2 Limited | Real estate | 2018 |
| Big Picture Training and Learning Design Ltd | Professional & scientific | 2022 |
| BIO Energy (UK) Limited | Financial services | 1997 |
| Biodonum Brands Ltd | Wholesale & retail | 2026 |
| Biovate Hygienics Limited | Wholesale & retail | 2022 |
| BJD Engineering Ltd | Professional & scientific | 2020 |
| Black N Rounds Limited | Wholesale & retail | 2014 |
| Black Olive Leadership Ltd | Professional & scientific | 2025 |
| Blake Enterprises Ltd | Wholesale & retail | 2026 |
| Blas Group Ltd | Wholesale & retail | 2022 |
| Blisworth Hill Finance Ltd | Extraterritorial | 2023 |
| Blisworth Hill Holdings Limited | Financial services | 2023 |
| Blisworth Hill Offices Ltd | Real estate | 2023 |
| Blisworth Hill Properties Limited | Professional & scientific | 2003 |
| Blisworth Hill Renewables Ltd | Energy | 2023 |
| Blisworth Hill Services Ltd | Extraterritorial | 2023 |
| BLM Group UK Ltd | Wholesale & retail | 1997 |
| Block & Beam Building Consultancy Ltd | Professional & scientific | 2026 |
| Blood Records Limited | Manufacturing | 2018 |
| Bloom Bakehouse Limited | Wholesale & retail | 2022 |
| Bloom Bookkeeping Services Ltd | Professional & scientific | 2024 |
| Bloom Fine Art Limited | Other services | 2020 |
| Blue Collar Catering Company Ltd | Hospitality | 2024 |
| Blue Falcon Publishing Limited | Information & communication | 2016 |
| Blue Line Canal Carriers Ltd | Extraterritorial | 2012 |
| BM PVT Ltd | Health & social care | 2019 |
| BMG Trading Services Ltd | Wholesale & retail | 2026 |
| BN Curry House Limited | Hospitality | 2024 |
| Bobbuster Ltd | Other services | 2025 |
| Bodystreet Training (UK) Limited | Arts & recreation | 2015 |
| Boehm + Wiedemann Ltd | Wholesale & retail | 2015 |
| Boke Racing Ltd | Arts & recreation | 2024 |
| Boldly Premium Subscription Staffing Ltd | Extraterritorial | 2019 |
| Bombina Services Ltd | Administrative & support | 2021 |
| Bonobo Management Solutions Limited | Professional & scientific | 2017 |
| Bookaskip Limited | Information & communication | 2020 |
| Bootcamp Events Limited | Arts & recreation | 2019 |
| Born to Grip Ltd | Professional & scientific | 2019 |
| Boughtons Estate Agents Ltd | Real estate | 2016 |
| Bouncer's Ltd | Manufacturing | 2015 |
| Bowler Logistics Limited | Transport & logistics | 2002 |
| Bowrovia Estates Limited | Real estate | 2014 |
| Boxer Machine Tool Services Ltd. | Manufacturing | 2002 |
| Boxers Body Ltd | Arts & recreation | 2025 |
| Boxology Limited | Wholesale & retail | 2016 |
| Boxwood Topco Limited | Financial services | 2026 |
| BP2017 (Hastingwood) LLP | | 2019 |
| BP2017 (MLI) LLP | | 2018 |
| Bradley Brown Consulting Ltd | Professional & scientific | 2015 |
| Bramhill Consulting Limited | Financial services | 2008 |
| Brampton Valley Group Ltd | Agriculture & fishing | 2012 |
| Brampton Valley Holdings Ltd | Financial services | 2022 |
| Brampton Valley Training & Assessments Ltd | Agriculture & fishing | 2022 |
| Brand Dynamix Limited | Professional & scientific | 2013 |
| Braz Harwood Limited | Professional & scientific | 2009 |
| Brazell Engineering Limited | Wholesale & retail | 2008 |
| Brdc Race Limited | Extraterritorial | 1998 |
| Breathewell Ltd | Health & social care | 2020 |
| Brennan Building & Civil Engineering Limited | Construction | 1998 |
| Brewhaus Coffee Ltd | Hospitality | 2025 |
| Brick Fayre Limited | Administrative & support | 2024 |
| Bride Like ME Ltd | Other services | 2018 |
| Bridge Street Northampton UK Limited | Real estate | 2024 |
| Bright Pixel (UK) Limited | Information & communication | 2007 |
| Brightside Lifestyle Limited | Real estate | 2023 |
| Brip 10 (Edinburgh) LLP | | 2023 |
| Brip 10 (Horley) LLP | | 2024 |
| Brip 10 (Houghton) LLP | | 2024 |
| Brip 10 (Kidbrook Godalming) LLP | | 2024 |