| Back in Control Solutions Limited | Administrative & support | 2020 |
| Back Office Outsourcing Ltd | Professional & scientific | 2025 |
| Back on Track Manchester Ltd | Education | 1992 |
| Back on Track Sports Physio Ltd | Arts & recreation | 2024 |
| Back Piccadilly (NO.1) Limited | Professional & scientific | 2017 |
| Back Piccadilly (NO.2) Limited | Professional & scientific | 2017 |
| Back Pocket Software Ltd | Information & communication | 2025 |
| Back Sitwell Limited | Households | 2022 |
| Back to Back Care Ltd | Administrative & support | 2016 |
| Back to Self Ltd | Arts & recreation | 2024 |
| Back to the Bible Broadcast Ltd | Other services | 2008 |
| BACK2BATH Limited | Manufacturing | 2013 |
| Backend Nexus Ltd | Information & communication | 2024 |
| Backfire Studios Ltd | Information & communication | 2026 |
| Backhale Limited | Manufacturing | 2024 |
| Backhaus International Ltd | Wholesale & retail | 2024 |
| Backstory Productions Ltd | Information & communication | 2021 |
| Backsuper Limited | Administrative & support | 1997 |
| Bactech Food Service Engineers Ltd | Professional & scientific | 2021 |
| Bacup Limited | Real estate | 2020 |
| Bacwa Ltd | Hospitality | 2019 |
| Bacwa Trading Ltd | Hospitality | 2019 |
| Bacwwr Ltd | Hospitality | 2019 |
| Bacwwr Trading Ltd | Hospitality | 2019 |
| BAD Breeding Limited | Arts & recreation | 2015 |
| BAD KAT Retail Company Limited | Wholesale & retail | 2024 |
| BAD Tasty Ltd | Information & communication | 2025 |
| Bada Bing Properties Ltd | Real estate | 2020 |
| Badar Sakandar Logistics Ltd | Transport & logistics | 2025 |
| Badat Locums Ltd | Health & social care | 2015 |
| Badatz Certification Ltd | Other services | 2018 |
| Badayie Alkhalij Ltd | Wholesale & retail | 2025 |
| Badboy Kebabs Ltd | Hospitality | 2025 |
| Badentoy Assets (NO 2) Limited | Extraterritorial | 2012 |
| Badentoy Assets NO 1 Limited | Extraterritorial | 2012 |
| Badfella Ltd | Wholesale & retail | 2025 |
| Badger Energy Limited | Manufacturing | 2021 |
| Badgers Croft Management (Little Sutton) Limited | Households | 2004 |
| Badgers Oak Properties Limited | Real estate | 2025 |
| Badgeworth Properties Limited | Real estate | 2019 |
| Badham Anaesthesia Limited | Health & social care | 2025 |
| Badhan Enterprises Ltd | Hospitality | 2017 |
| Badly Drawn BOY Music Limited | Arts & recreation | 2001 |
| Badmash Originals Ltd | Wholesale & retail | 2023 |
| Badmus Group Limited | Professional & scientific | 2018 |
| Badmus House Enterprise Limited | Real estate | 2026 |
| Badosa Ltd | Financial services | 2023 |
| Badr Sport Ltd | Wholesale & retail | 2017 |
| BAE Events Limited | Administrative & support | 2018 |
| BAF Blindenarbeit Group Ltd | Wholesale & retail | 2023 |
| Bafa Enterprise Ltd | Real estate | 2020 |
| Bafa Services Ltd | Construction | 2018 |
| Baffo Properties Ltd | Real estate | 2025 |
| BAG LAB UK Limited | Wholesale & retail | 2023 |
| BAG Lane Minimart Ltd | Wholesale & retail | 2020 |
| BAG Studio House Limited | Wholesale & retail | 2025 |
| BAG Studio Ltd | Wholesale & retail | 2026 |
| Bagbloxx Ltd | Wholesale & retail | 2022 |
| Bagel Dog Ltd | Hospitality | 2025 |
| Bagels at F Ltd | Hospitality | 2025 |
| Bagels at Fifty Ltd | Hospitality | 2025 |
| Bagels Burgers Beers Ltd | Hospitality | 2023 |
| Baggi's Trading Ltd | Wholesale & retail | 2024 |
| Baghdad Cheetham Hill Ltd | Hospitality | 2024 |
| Baghdadi Traders Ltd | Hospitality | 2024 |
| Bagita Living Limited | Wholesale & retail | 2020 |
| Bags and Luggage Direct Ltd | Wholesale & retail | 2023 |
| BAGS4U Ltd | Wholesale & retail | 2025 |
| Bagthing Limited | Professional & scientific | 2016 |
| Baguley MOT Centre Limited | Wholesale & retail | 2004 |
| Bagverse Ltd | Wholesale & retail | 2025 |
| Bahaar Banoo Limited | Wholesale & retail | 2024 |
| Bahamian Enterprise UK Limited | Wholesale & retail | 2018 |
| Bahar Rasul Limited | Health & social care | 2021 |
| Baharan Limited | Real estate | 2026 |
| Bahari Property Ltd | Real estate | 2025 |
| Bahati Care Limited | Health & social care | 2014 |
| Baher Way Ltd | Wholesale & retail | 2025 |
| Bahh NQ Limited | Hospitality | 2025 |
| Bahijaan Motors Limited | Wholesale & retail | 2023 |
| Bahjat Noor Ltd | Education | 2024 |
| Bahob Ltd | Wholesale & retail | 2018 |
| Bahr AL Yaqoot Company Ltd | Wholesale & retail | 2025 |
| Bahr EL Konoz Ltd | Wholesale & retail | 2025 |
| Bahria Town Real Estate Limited | Construction | 2025 |
| BAHVENTURE25 Limited | Health & social care | 2023 |
| Baiboon Thai Therapy Ltd | Other services | 2023 |
| Baiboon Therapy Limited | Other services | 2023 |
| Baida Clothing Co., Ltd | Wholesale & retail | 2022 |
| Baier Group (UK) Biology Engineering Ltd | Extraterritorial | 2021 |
| Baig & Co Investments Ltd | Real estate | 2019 |
| Baig Health Ltd | Wholesale & retail | 2022 |
| Bailey & Fawcett Ltd | Real estate | 2025 |
| Bailey & Halsall Limited | Professional & scientific | 2014 |
| Bailey Campbell Property Management Limited | Real estate | 2023 |
| Bailey Instruments Ltd | Manufacturing | 1989 |
| Bailey Pipework Limited | Construction | 2013 |
| Bailey Roberts Property Management Ltd | Real estate | 2023 |
| Bailey UK Projects Ltd | Construction | 2014 |
| Bailey Wilson Construction and Property Consultants Limited | Other services | 2016 |