| Birch & Bean Ltd | Hospitality | 2025 |
| Birch Improvement Limited | Professional & scientific | 2019 |
| Birch Park Management Company Limited | Extraterritorial | 2005 |
| Birch Projects Limited | Other services | 2011 |
| Birch's Tavern Ltd | Hospitality | 2023 |
| Birchen Properties Limited | Construction | 2023 |
| Birchfield Activity Kits and Toys Ltd | Wholesale & retail | 2024 |
| Birchwood Bespoke Joinery Limited | Manufacturing | 2017 |
| Birchwood Tutors Ltd | Education | 2020 |
| Birchwoode Entertainment Ltd | Extraterritorial | 2025 |
| Birco Group Ltd | Financial services | 2026 |
| Bird & Mcguinness Limited | Construction | 2003 |
| Birdbox Imports Limited | Wholesale & retail | 2020 |
| Birdham Pool Ltd | Real estate | 1942 |
| Birdham Shipyard Ltd | Real estate | 1947 |
| Birdlight Design Ltd | Arts & recreation | 2024 |
| Birds 4 Homes Ltd | Wholesale & retail | 2020 |
| Birds Home Services Ltd | Real estate | 2025 |
| Birdsnest 1 Ltd | Construction | 2015 |
| Birdtop Limited | Financial services | 2020 |
| Birdypops Limited | Wholesale & retail | 2018 |
| Biren Healthcare Limited | Health & social care | 2026 |
| Biriyani HUT Ltd | Hospitality | 2024 |
| Birkett & Birkett Limited | Financial services | 2021 |
| Birks Venue Limited | Hospitality | 2024 |
| Birley Spa News Ltd | Wholesale & retail | 2015 |
| Birlim Litho (2007) Limited | Manufacturing | 2007 |
| Birlim Litho Limited | Administrative & support | 1966 |
| Birmingham Highways Limited | Transport & logistics | 2009 |
| Birring Property Investment Ltd | Real estate | 2025 |
| Birring Property Renovation Ltd | Construction | 2025 |
| Birth Artist Management Limited | Professional & scientific | 2020 |
| Biryani Direct Ltd | Hospitality | 2024 |
| Biryaniz Ltd | Hospitality | 2021 |
| Bis.Ai.Ai Ltd | Real estate | 2024 |
| Biscuit and Brew Ltd | Hospitality | 2020 |
| Bishop Consulting Limited | Professional & scientific | 2022 |
| Bishop Properties (Nottm) Ltd | Real estate | 2025 |
| Bishop Property Consultants Limited | Real estate | 2016 |
| Bishops Wycombe Lettings Limited | Real estate | 2024 |
| Bishops Wycombe Limited | Construction | 2023 |
| Bishopsgate Global Concept Limited | Health & social care | 2019 |
| Bishwa & Sarita Properties Limited | Real estate | 2025 |
| Bisirat Unisex Salon Limited | Other services | 2024 |
| Bismah Outlet Ltd | Wholesale & retail | 2021 |
| Bismi Rabbi Limited | Wholesale & retail | 2023 |
| Bismillah 786 Holdings Ltd | Financial services | 2021 |
| Bismillah 786 Properties Ltd | Real estate | 2021 |
| Bismillah Foodstore Limited | Wholesale & retail | 2012 |
| Bison Painting and Refurbishments Limited | Construction | 2017 |
| Bissau Exploration Company Ltd | Mining & quarrying | 2015 |
| Bistro Mila Cafe Ltd | Hospitality | 2019 |
| BIT and Blade Ltd | Wholesale & retail | 2015 |
| BIT4 Limited | Manufacturing | 2013 |
| Bitastreet Limited | Wholesale & retail | 2024 |
| Bitbiga Tech Solutions Ltd | Wholesale & retail | 2025 |
| Bitcommerce Limited | Wholesale & retail | 2023 |
| Bitg Limited | Real estate | 2013 |
| Bitg Properties Limited | Real estate | 2020 |
| Bits at Micks Limited | Water & waste | 2006 |
| Bitsecure Ltd | Information & communication | 2019 |
| Bitstream Services Limited | Information & communication | 2016 |
| Bitterling Equipment Limited | Wholesale & retail | 2005 |
| Bitwise Consultancy Ltd | Information & communication | 2025 |
| Biwad Window Cleaning Limited | Administrative & support | 2020 |
| Bixu Ltd | Construction | 2025 |
| Biyock Services Limited | Wholesale & retail | 2020 |
| Biztax Accounting and Consultancy Ltd | Professional & scientific | 2025 |
| Bizz Energy Collections Limited | Professional & scientific | 2009 |
| Bizzy Kidz Limited | Education | 2006 |
| Bizzy Kidz Nursery Limited | Education | 2007 |
| BJ Carver Limited | Arts & recreation | 2016 |
| BJ Traders Ltd | Wholesale & retail | 2025 |
| Bjcs Media Ltd | Information & communication | 2026 |
| BJD Motors Ltd | Wholesale & retail | 2026 |
| BJK Kebab Ltd | Hospitality | 2026 |
| BJM Flooring and Supplies Ltd | Construction | 2000 |
| BJS Dental Limited | Professional & scientific | 2015 |
| BJS Solutions Limited | Administrative & support | 2025 |
| BJW Services Ltd | Construction | 2015 |
| BK Maintenance Ltd | Real estate | 2024 |
| BK the Willows Ltd | Real estate | 2023 |
| BK Transport & Forklift Services Limited | Transport & logistics | 2022 |
| BKG Gallego Ltd | Transport & logistics | 2026 |
| BKK Trading Ltd. | Wholesale & retail | 2024 |
| BKM Build Ltd | Real estate | 2024 |
| BKR Care Limited | Financial services | 2014 |
| BKR CCH Limited | Health & social care | 2014 |
| BKR Homes Limited | Real estate | 2014 |
| BKS Home Improvements Ltd | Construction | 2025 |
| BKS Martial Arts & Fitness Limited | Arts & recreation | 2025 |
| BKS Prop Ltd | Real estate | 2026 |
| Bkse Limited | Arts & recreation | 2023 |
| BKU Services Ltd | Wholesale & retail | 2022 |
| BL Plumbers Nottingham Ltd | Construction | 2019 |
| BL Sellers Ltd | Wholesale & retail | 2022 |
| BL TKD LLP | | 2020 |
| Black Achievers Awards CIC | Administrative & support | 2025 |
| Black and Proud CIC | Professional & scientific | 2024 |
| Black and White C N C Services Limited | Manufacturing | 2012 |