| Bmefit Ltd | Other services | 2019 |
| BMS Commissions Limited | Energy | 2006 |
| BMS London Ltd | Financial services | 2022 |
| BNC Works Limited | Construction | 2025 |
| Bnch Healthcare Limited | Health & social care | 2022 |
| BNG Habitat Sites Ltd | Real estate | 2026 |
| BO & Co Accountants Ltd | Professional & scientific | 2020 |
| BOB IT & Media Solutions Ltd | Information & communication | 2023 |
| Bob-Ski Limited | Construction | 2019 |
| Bodeli Consultants Limited | Manufacturing | 2017 |
| Bodeli Empire Limited | Real estate | 2021 |
| Bodiedby Nessaa Limited | Wholesale & retail | 2025 |
| BODOS85 Limited | Construction | 2026 |
| Body Contour by YAZ Limited | Other services | 2024 |
| Body Logic SQ Ltd | Health & social care | 2025 |
| Bodysense UK Ltd | Arts & recreation | 2009 |
| BOE Consultancy Limited | Construction | 2024 |
| Bohzo Ltd | Information & communication | 2023 |
| Bolafem Ltd | Health & social care | 2018 |
| Boldbase Ltd | Construction | 2026 |
| Bolly Sky Ltd | Health & social care | 2023 |
| Bolton & Sons Ltd | Real estate | 2013 |
| Bond Retail Marketing Limited | Wholesale & retail | 1993 |
| Boneville Limited | Manufacturing | 2011 |
| Bongbrit Ltd | Other services | 2022 |
| Bonhams Electrical Ltd | Construction | 2020 |
| Bonis Supported Living Ltd | Health & social care | 2024 |
| Bonlec Limited | Construction | 2014 |
| Bonni Logistics Ltd | Transport & logistics | 2020 |
| Bonnie Rose Holdings Ltd | Financial services | 2024 |
| Bonzai Entertainment Ltd | Information & communication | 2021 |
| Bonzo Capital Ltd | Financial services | 2025 |
| Book on Solutions Limited | Information & communication | 2024 |
| Bookerboys Ltd | Construction | 2025 |
| Bookngo Limited | Information & communication | 2013 |
| Boom Couriers Limited | Transport & logistics | 2016 |
| Boom Hair Limited | Other services | 2025 |
| Boom Property Ltd | Real estate | 2021 |
| Boom Sports Coaching Ltd | Education | 2024 |
| Booth Junkie Ltd | Information & communication | 2017 |
| Borbe Cad(Computer Aided Design) Services Limited | Information & communication | 2014 |
| Borough Consulting Limited | Administrative & support | 2010 |
| Bosenn Limited | Real estate | 2016 |
| Bosi Couriers Ltd | Transport & logistics | 2018 |
| Bosp Brighter Opportunities for Special People | Health & social care | 2004 |
| Boss Brewing Company Ltd | Manufacturing | 2014 |
| Boston Studio Ltd | Professional & scientific | 2011 |
| Botlab Technologies Limited | Information & communication | 2023 |
| Bouhadna Chiropractic Limited | Public administration | 2024 |
| Boultbee Brooks (Lamb Walk) LLP | | 2014 |
| Boutique Baller London Limited | Arts & recreation | 2019 |
| Bovill Group Holdings Limited | Construction | 2026 |
| Bowers Gifford Care Village Limited | Construction | 2015 |
| Bowler Developments Limited | Construction | 2003 |
| Bowler Fixings and Supplies Ltd | Wholesale & retail | 2024 |
| Bowler Group Limited | Transport & logistics | 1998 |
| Bowler Powder Coating Ltd | Manufacturing | 2022 |
| Bowman Building Works Ltd | Manufacturing | 2025 |
| Bowtox Beauty Ltd | Other services | 2023 |
| Box Gym Fitness Ltd | Arts & recreation | 2018 |
| Box Made Ltd | Information & communication | 2020 |
| Boxers Barbers Ltd | Administrative & support | 2014 |
| Boyce Construction Company Limited | Construction | 2004 |
| Boyle Decorating Services Ltd | Construction | 2017 |
| Boyles Court Management Company Limited | Professional & scientific | 2021 |
| Boyotech Limited | Information & communication | 2019 |
| BP Film & TV Transport Limited | Transport & logistics | 2023 |
| BPD Scaffolding Ltd | Construction | 2026 |
| BPH Couriers Limited | Other services | 2025 |
| BPS (Bulk Powder Solutions) Limited | Administrative & support | 2005 |
| BPS Building Services Ltd | Construction | 2023 |
| BPS Modelling Ltd | Professional & scientific | 2019 |
| BPS Plumbing Limited | Construction | 2019 |
| BQS Handymen Ltd | Construction | 2025 |
| Brackcluin Ltd | Professional & scientific | 2022 |
| Bradley Scott Electrical Services Ltd | Construction | 2011 |
| Brambley Furniture Limited | Manufacturing | 2005 |
| Branchflower Consultancy Services Limited | Professional & scientific | 2014 |
| Brand Alliance (License) Limited | Wholesale & retail | 2017 |
| Brand Alliance Holdings Limited | Administrative & support | 2007 |
| Brand Alliance Trustee Limited | Wholesale & retail | 2025 |
| Brand Elect Limited | Professional & scientific | 2016 |
| Brand Nation Design Ltd | Professional & scientific | 2018 |
| Branded Stocks (Charlie) Limited | Manufacturing | 2008 |
| Branded Stocks (Europe) Limited | Wholesale & retail | 1997 |
| Branded Stocks (UK) Ltd | Real estate | 1993 |
| Branded Stocks Benelux Limited | Wholesale & retail | 2012 |
| Branded Stocks Charter Worldwide Limited | Administrative & support | 2006 |
| Branded Stocks Holdings Limited | Wholesale & retail | 1999 |
| Branded Stocks Properties Limited | Real estate | 2006 |
| Branded Stocks Retail Ltd | Wholesale & retail | 2006 |
| Branded Stocks Worldwide Limited | Financial services | 2020 |
| Branksome Payroll Limited | Financial services | 2018 |
| Brass Key Holdings Ltd | Real estate | 2025 |
| BRD Automotive Limited | Wholesale & retail | 2021 |
| BRD Property Group Limited | Real estate | 2025 |
| Breckland (Shenfield) Management Company Limited | Administrative & support | 1983 |
| Breeze Caribbean Limited | Hospitality | 2018 |
| Brendata (UK) Limited | Information & communication | 1992 |
| Brentwood Lofts Limited | Construction | 2007 |