| Bhardwaj Private Ltd. | Health & social care | 2026 |
| BHF Environmental Limited | Professional & scientific | 1994 |
| BHI Building Services Ltd | Construction | 2017 |
| Bickerton Electrical Services Limited | Construction | 2017 |
| Bicuspid Limited | Health & social care | 2023 |
| Biedronka Limited | Extraterritorial | 2007 |
| Big Al's Sandwich Ltd | Hospitality | 2025 |
| Big Bang Media Ltd | Information & communication | 2012 |
| Big Belly Entertainment Limited | Arts & recreation | 2022 |
| Big Green Planet Ltd | Wholesale & retail | 2009 |
| Big Wick Energy Ltd | Wholesale & retail | 2025 |
| Bigcart Ltd | Wholesale & retail | 2026 |
| Bigger Boat Limited | Information & communication | 2007 |
| Bijou Property Investments Ltd | Real estate | 2018 |
| Bike Shack Limited | Real estate | 2024 |
| Bikini Bottom Ltd | Hospitality | 2024 |
| Bila Care Services Ltd | Health & social care | 2024 |
| Bilalsub Limited | Wholesale & retail | 2026 |
| Bill Mann (Properties) Limited | Real estate | 2016 |
| Bill Mann Limited | Real estate | 2013 |
| Bill Willett Antiques & Jewellery Ltd | Wholesale & retail | 2017 |
| Billett Homes Ltd | Construction | 2025 |
| BIM Alpha Limited | Professional & scientific | 2025 |
| Binsteed Childcare Services Limited | Health & social care | 2003 |
| BIO Response Asbestos Ltd | Water & waste | 2025 |
| BIO Response Ltd | Administrative & support | 2020 |
| BIO Restoration South Ltd | Administrative & support | 2023 |
| Biosero Limited | Information & communication | 2018 |
| Biovie Ltd | Health & social care | 2023 |
| Birdcage Movie Ltd | Information & communication | 2020 |
| Birdham Limited | Hospitality | 2026 |
| Birkendale Consulting Ltd | Professional & scientific | 2026 |
| Birmingham Powder Coatings Limited | Manufacturing | 1996 |
| Biscoes Law Limited | Professional & scientific | 2014 |
| Biscoes Legal Services Limited | Professional & scientific | 2017 |
| Bishops Printers Limited | Manufacturing | 1992 |
| Bissett & Robson Ltd | Construction | 2008 |
| Biykscare Ltd | Health & social care | 2024 |
| Bizwheels Limited | Wholesale & retail | 2025 |
| Bjtj Southern Limited | Construction | 2015 |
| BL Branson Ltd | Financial services | 2024 |
| Black Art Graphics Ltd | Arts & recreation | 2025 |
| Black Duck UAV Limited | Professional & scientific | 2018 |
| Black Gang Marine Ltd | Manufacturing | 2018 |
| Black Lotus Plumbing and Electrical Ltd | Construction | 2024 |
| Black Lynx Ltd | Construction | 2021 |
| Black Mountain Montenegro Ltd | Administrative & support | 2006 |
| Black Panther (Surrey) Ltd | Real estate | 2021 |
| Black Panther Capital Ltd | Financial services | 2019 |
| Black Panther Management Limited | Real estate | 2014 |
| Black Panther Property Ltd | Real estate | 2016 |
| Black Rose Property Limited | Hospitality | 2019 |
| Black Sultan Consultants Limited | Other services | 2019 |
| Blackbox Creative Studios Ltd | Professional & scientific | 2025 |
| Blackfield Associates Limited | Extraterritorial | 2017 |
| BLACKTALON21 Ltd | Health & social care | 2025 |
| Blade Bricklaying Limited | Construction | 2018 |
| Blade Ninja Limited | Construction | 2021 |
| Blades Electrical Services Ltd | Construction | 2004 |
| Blaise Consultants Limited | Professional & scientific | 2013 |
| Blake GRP Roofing Ltd | Construction | 2018 |
| Blake Porter Limited | Real estate | 2026 |
| Blakely & Time Property Investment Ltd | Real estate | 2026 |
| Blakeside Management Limited | Households | 1998 |
| Blanchard Fields (Cowes) Limited | Construction | 2026 |
| Blanchard Fields (Social) Limited | Construction | 2018 |
| Blanchard Fields Limited | Construction | 2018 |
| Blaze P R Limited | Professional & scientific | 2009 |
| Blazingharmony Ltd | Hospitality | 2025 |
| Blendworth Medical Limited | Health & social care | 2016 |
| Blenheim Builders Limited | Construction | 2016 |
| Blenheim Christmas Market Ltd | Arts & recreation | 2024 |
| Blessing Sparkling Cleaning Ltd | Administrative & support | 2025 |
| Blinkbi Ltd | Information & communication | 2020 |
| Blinkbuyuk Ltd | Wholesale & retail | 2026 |
| Bliss Drinks Ltd | Wholesale & retail | 2023 |
| Bloc Engineering Consultants Limited | Professional & scientific | 2021 |
| Bloomfields Group Limited | Financial services | 2024 |
| Bloomfields Investment Properties Limited | Real estate | 2024 |
| Bloomsbury Marble Art Limited | Construction | 2024 |
| Blowing Stone Hospitality Limited | Hospitality | 2020 |
| BLT Automations Ltd | Information & communication | 2026 |
| Blue & Snow Limited | Health & social care | 2013 |
| Blue Agent Ltd | Health & social care | 2018 |
| Blue Bear Properties Limited | Real estate | 2015 |
| Blue Bombini Limited | Professional & scientific | 2017 |
| Blue BOY Properties Ltd | Real estate | 2024 |
| Blue Cobra Portsmouth Ltd | Hospitality | 2019 |
| Blue Donut Games Ltd | Manufacturing | 2021 |
| Blue Donut Studios Limited | Professional & scientific | 2015 |
| Blue Freedom Properties Ltd | Real estate | 2020 |
| Blue Harbour Creative Media Limited | Information & communication | 2004 |
| Blue Iris Healthcare Ltd | Health & social care | 2021 |
| Blue Marble Associates Limited | Information & communication | 2006 |
| Blue Mountain Living Limited | Real estate | 2019 |
| Blue Ocean FRY Ltd | Hospitality | 2026 |
| Blue Piranha Branded Clothing Limited | Wholesale & retail | 2007 |
| Blue Property South Ltd | Real estate | 2026 |
| Blue Ridge Property Solutions Ltd | Real estate | 2016 |
| Blue Technical Ltd | Construction | 2019 |