| Black Anchor Heavy Industries Ltd | Manufacturing | 2017 |
| Black Cat Fireworks Limited | Wholesale & retail | 1985 |
| Black Crown Dynasty Ltd | Wholesale & retail | 2020 |
| Black Horse Trading Limited | Health & social care | 2024 |
| Black Impact Ltd | Education | 2019 |
| Black Lion Hotel Manchester Limited | Wholesale & retail | 2019 |
| Black Rock CBD Ltd | Wholesale & retail | 2021 |
| Black Ventures Ltd | Professional & scientific | 2026 |
| Black Venus Beauty Distribution Ltd | Wholesale & retail | 2019 |
| Black Wall Art Collective CIC | Education | 2025 |
| Black Watch Security Ltd | Administrative & support | 2016 |
| Black Watch Security Services Limited | Administrative & support | 2016 |
| Black Watch Tactical Ltd | Administrative & support | 2015 |
| Blackfield Services Limited | Administrative & support | 2026 |
| Blackfriar Pictures Ltd | Information & communication | 2024 |
| Blackfriars Grocers Ltd | Wholesale & retail | 2018 |
| Blackfriars MCR Limited | Hospitality | 2021 |
| Blackhall Colliery Estates Limited | Other services | 2025 |
| Blackhorse Blackrod Holdings Limited | Other services | 2026 |
| Blacklink Legal Indemnities Ltd | Financial services | 2023 |
| Blackmont Group Ltd | Professional & scientific | 2026 |
| Blackpool Medicare Limited | Real estate | 2022 |
| Blackpool Partnership Ltd | Other services | 2024 |
| Blackpool Retail Estates Limited | Other services | 2023 |
| Blacksquare Beer Ltd | Wholesale & retail | 2019 |
| Blackstar Exchange Ltd | Wholesale & retail | 2026 |
| Blackstone Site Services Limited | Professional & scientific | 2025 |
| Blackstones Properties Ltd | Real estate | 2022 |
| Blackwell Security Services Limited | Administrative & support | 2014 |
| Blandford Neches Ltd | Extraterritorial | 2025 |
| Blandwick Limited | Professional & scientific | 1994 |
| Blau Estates Ltd | Real estate | 2017 |
| Blau Real Estate Ltd | Real estate | 2018 |
| Blemee Estates Ltd | Real estate | 2021 |
| Blessed Mani Rajammal Limited | Health & social care | 2025 |
| Blessing and Success Real Estates Ltd | Real estate | 2022 |
| Blind Investment Ltd | Real estate | 2018 |
| Blip Property Ltd | Real estate | 2020 |
| Bliss Route Courier Ltd | Transport & logistics | 2026 |
| Blocks Realty Ltd | Real estate | 2024 |
| Bloom Commercial Enterprises Limited | Real estate | 2017 |
| Bloom Commercial Properties Limited | Real estate | 2019 |
| Bloom&Brick Limited | Wholesale & retail | 2025 |
| Bloomark Group Ltd | Wholesale & retail | 2026 |
| Bloompool Investments Limited | Real estate | 2022 |
| Blue Diamond Creative Limited | Other services | 2017 |
| Blue Express Limited | Transport & logistics | 2024 |
| Blue EYE Security Limited | Construction | 2026 |
| Blue Flag Accident Management Limited | Transport & logistics | 1998 |
| Blue Horse Developments Limited | Professional & scientific | 2006 |
| Blue Line North Limited | Real estate | 2019 |
| Blue Moon Blue Sky Limited | Administrative & support | 2011 |
| Blue Nile Logistics Ltd | Transport & logistics | 2026 |
| Blue Otter Limited | Professional & scientific | 2020 |
| Blue Sky Online Store Ltd | Wholesale & retail | 2026 |
| Bluebell Court Care Home Limited | Health & social care | 2021 |
| Bluebells Community Club | Other services | 2021 |
| Bluebells Estates Limited | Real estate | 2020 |
| Blueberries Estates Ltd | Real estate | 2020 |
| Blueberries Freehold Ltd | Real estate | 2025 |
| Blueeast Estates Ltd | Real estate | 2026 |
| Bluefig Investments (UK) Limited | Real estate | 2014 |
| Bluefig Investments LLP | | 2010 |
| Bluefire Accountancy Ltd | Professional & scientific | 2020 |
| Bluegates Estates Ltd | Real estate | 2020 |
| Bluegates Freehold Ltd | Real estate | 2024 |
| Bluekey Property Management Ltd | Real estate | 2025 |
| Blueland Estates Ltd | Real estate | 2021 |
| Bluelead Technologies Ltd | Information & communication | 2025 |
| Bluelife Estates Ltd | Real estate | 2023 |
| Bluenorth Estates Ltd | Real estate | 2025 |
| Bluepark Group Ltd | Real estate | 2024 |
| Bluepark Management Ltd | Real estate | 2022 |
| Blueparks Estates Ltd | Real estate | 2021 |
| Blueparks Freehold Ltd | Real estate | 2022 |
| Bluepatches Services Limited | Wholesale & retail | 2015 |
| Blueprint Property & Finance Ltd | Construction | 2025 |
| Bluesave Estates Ltd | Real estate | 2024 |
| Blueshift Estates Ltd | Real estate | 2024 |
| Blueshift Freehold Ltd | Real estate | 2025 |
| Bluesimple Estates Ltd | Real estate | 2022 |
| BLUESKY556 Ltd | Hospitality | 2025 |
| Bluespink Estates Ltd | Real estate | 2022 |
| Bluesplit Estates Ltd | Real estate | 2023 |
| Bluesplit Freehold Ltd | Real estate | 2023 |
| Bluewarp Limited | Manufacturing | 2021 |
| Bluewest Estates Ltd | Real estate | 2026 |
| Bluewool Properties Limited | Real estate | 2022 |
| Blujay Solutions Holdings Limited | Information & communication | 2012 |
| Blujay Solutions Ltd | Information & communication | 1972 |
| Blyth Estates Holdings Limited | Other services | 2022 |
| BM Property Investing Limited | Real estate | 2025 |
| BM Urban Properties Ltd | Real estate | 2025 |
| BM Window Cleaning Service Ltd | Administrative & support | 2023 |
| BM4 Foods, Events, and Catering Services Ltd | Hospitality | 2024 |
| Bmac Homes Limited | Households | 2025 |
| BMJ Emporium Ltd | Administrative & support | 2022 |
| BMN APL Limited | Construction | 2016 |
| BMN BT Limited | Construction | 2016 |
| BMN Chapel Street Limited | Construction | 2016 |