| Bicton Developments | Construction | 2021 |
| BID by Design Ltd | Other services | 2018 |
| Biddulph Mansions (West) Limited | Real estate | 1977 |
| Big 5 Catering Ltd | Hospitality | 2025 |
| Big Fresh UK Limited | Administrative & support | 2009 |
| Big Hive Ltd | Professional & scientific | 2025 |
| Big HR Limited | Administrative & support | 2017 |
| Big in Brands Limited | Wholesale & retail | 2017 |
| Big Tree Associates Limited | Wholesale & retail | 2013 |
| Bigblue Product Design Limited | Wholesale & retail | 2003 |
| Bigfoot Distribution Ltd | Wholesale & retail | 2024 |
| Biggs Trader Limited | Wholesale & retail | 2024 |
| Bignor Manchester LLP | | 2016 |
| Bigroc Accounting Limited | Professional & scientific | 2025 |
| Biite Coffee Limited | Hospitality | 2023 |
| Bike Re:Evolution Ltd | Wholesale & retail | 2019 |
| Bill Smith Motors Limited | Wholesale & retail | 1963 |
| Billgaurd UK Ltd | Information & communication | 2026 |
| Billy Decoration Limited | Construction | 2025 |
| BIM Enterprises Limited | Professional & scientific | 2008 |
| Bimmode Ltd | Real estate | 2022 |
| BIN B Gone Limited | Water & waste | 2025 |
| Binbag Apparel Ltd | Wholesale & retail | 2025 |
| Bio&Me Limited | Manufacturing | 2019 |
| Bio-Mech Physio Limited | Transport & logistics | 2014 |
| Biome Professionals Limited | Professional & scientific | 2019 |
| Biomodula Ltd | Construction | 2022 |
| Bion Invest Ltd | Real estate | 2024 |
| Birch Heath Developments Ltd | Construction | 2020 |
| Birchdale Farm Developments Limited | Construction | 2021 |
| Bird 25 Ltd. | Hospitality | 2024 |
| Birdy Lettings Ltd | Real estate | 2025 |
| Biri Solution Limited | Manufacturing | 2026 |
| Birkdale Bury Ltd | Real estate | 2021 |
| Birth Trauma Association | Health & social care | 2007 |
| Birtwisle & Co.,Limited | Transport & logistics | 1923 |
| Bishop Lloyd's Ltd | Hospitality | 2024 |
| Bishop's Place (Oxton) Management Company Limited | Real estate | 2015 |
| Bishopsgate Advances Limited | Financial services | 2004 |
| Bison 4X4 Limited | Wholesale & retail | 2015 |
| Bispham Road Pharmacy Limited | Extraterritorial | 2009 |
| BIT Group Ltd | Wholesale & retail | 2023 |
| Bithell Boats Limited | Transport & logistics | 1988 |
| Bitscape Digital Ltd | Information & communication | 2021 |
| BJH Directors Limited | Professional & scientific | 2024 |
| BJL Property Development Limited | Real estate | 2024 |
| BK Elec Limited | Construction | 2015 |
| BK IT Consultants Limited | Information & communication | 2010 |
| Bkwt Capital Limited | Professional & scientific | 2022 |
| Black Acre Rural Limited | Professional & scientific | 2025 |
| Black ASH Properties Limited | Manufacturing | 2019 |
| Black Book Experience Limited | Professional & scientific | 2024 |
| Black Citrine Ltd | Arts & recreation | 2022 |
| Black Flamingo Services Ltd | Wholesale & retail | 2015 |
| Black Founders Studio CIC | Professional & scientific | 2025 |
| Black Mango Art Ltd | Arts & recreation | 2017 |
| Black Mango Inc Ltd | Other services | 2012 |
| Black Marlin Ltd | Information & communication | 2012 |
| Black Omens Group Ltd | Wholesale & retail | 2019 |
| Black Rock Safety Ltd | Construction | 2019 |
| Black Sheep Transitions Limited | Manufacturing | 2018 |
| Black Sync Ltd | Wholesale & retail | 2013 |
| Blackberry Trading Ltd | Construction | 2020 |
| Blackburn Consult Ltd | Professional & scientific | 2017 |
| Blackburn Transport Ltd | Transport & logistics | 2021 |
| Blackfriars (Chester) Management Company Limited | Households | 1974 |
| Blackham Developments Limited | Construction | 2005 |
| Blackham Land East Limited | Construction | 2009 |
| Blackham Land West Limited | Construction | 2009 |
| Blackhat Defence Ltd | Information & communication | 2025 |
| Blackhouseleeds Ltd | Hospitality | 2026 |
| Blackhousetrade Ltd | Hospitality | 2026 |
| Blackoak Capital Partners Limited | Financial services | 2021 |
| Blackoak Intermediate Life Limited | Financial services | 2025 |
| Blackoak Intermediate LP | | 2025 |
| Blackoak Investors LP | | 2013 |
| Blackoak Life Limited | Financial services | 2013 |
| Blackpoint Design Ltd | Professional & scientific | 2016 |
| Blackrain Medical Limited | Health & social care | 2017 |
| Blackridge Commercial Intelligence Ltd | Professional & scientific | 2026 |
| Blackrock Medical Recruitment Limited | Administrative & support | 2017 |
| Blacksheep Advertising Limited | Professional & scientific | 2021 |
| Blacksite Tactical Ltd | Manufacturing | 2026 |
| Blackstar Ventures Limited | Financial services | 2019 |
| Blackstone Outreach Ltd | Professional & scientific | 2025 |
| Blackwall Funding Solutions LLP | | 2024 |
| Blackwood Construction NW Ltd | Construction | 2022 |
| Blackwood Financial Planning Limited | Professional & scientific | 2025 |
| Blacon Fish Bar Ltd | Hospitality | 2025 |
| Blacon High School Trust | Education | 2010 |
| Blacon Sun Ltd | Other services | 2024 |
| Blake Bettley Enterprises Ltd | Information & communication | 2015 |
| Blank Canvas Pizzas Limited | Hospitality | 2026 |
| Blaqfire Limited | Information & communication | 2018 |
| Blayden Jones Limited | Professional & scientific | 2023 |
| Blekker Ltd | Wholesale & retail | 2025 |
| Blim (NW) Limited | Professional & scientific | 2012 |
| Bliss Bidco Limited | Administrative & support | 2016 |
| Bliss Newco Limited | Financial services | 2020 |
| Bliss Topco Limited | Administrative & support | 2016 |