| Becketts Rise Management Company (Basingstoke) Limited | Real estate | 2017 |
| Beechwood (Block R) Management Company Limited | Households | 1990 |
| Beechwood (Block S) Management Company Limited | Households | 1990 |
| Beechwood (Block V) Management Company Limited | Households | 1991 |
| Beechwood (Clayton LE Woods) Management Co Ltd | Households | 2009 |
| Beechwood Spinney Management Company Limited | Households | 1973 |
| Beefold Chase Management Company Limited | Households | 2025 |
| Beesee Windows Limited | Construction | 2019 |
| Beeston Place Residents Association Limited | Households | 2000 |
| Beeston Quarter Apartments (Beeston) Management Company Limited | Households | 2020 |
| Behrens Warehouse (Bradford) Management Company Limited | Households | 2003 |
| Being (Herts One) Ltd | Other services | 2025 |
| Being (Herts) Limited | Other services | 2026 |
| Being Group (UK) Limited | Financial services | 2026 |
| Belamenta Limited | Transport & logistics | 2015 |
| Belfry Services Ltd | Construction | 2018 |
| Belgrave House Residents Limited | Households | 2012 |
| Believe and Exceed Tutoring Ltd | Education | 2026 |
| Bella Construction Group Ltd | Construction | 2025 |
| Bella Wood View (Goldthorpe) Management Company Limited | Households | 2021 |
| BELLA@N9 Limited | Real estate | 2020 |
| Belle Marine Properties Limited | Real estate | 2012 |
| Belle Mart Ltd | Wholesale & retail | 2017 |
| Bells Hill Management Company Limited | Households | 2006 |
| Belmont Court (Finchley) Limited | Households | 1992 |
| Belmont Grange Ltd | Health & social care | 2013 |
| Belrok Ltd | Professional & scientific | 2026 |
| Belton Westgate Management Company Limited | Households | 2022 |
| Belvedere Foods Limited | Wholesale & retail | 1967 |
| BEN Wilson Consultants Ltd | Professional & scientific | 2025 |
| Benacre Investments Limited | Real estate | 1992 |
| Bengeo Meadows Management Co. Limited | Households | 1989 |
| Bengeo Playgroup Limited | Health & social care | 2013 |
| Bennallack Limited | Arts & recreation | 2008 |
| Bentley Bridge Park Management Company Limited | Households | 2000 |
| Bermondsey Central Management Company Limited | Households | 2010 |
| Bernard Capital Ventures Limited | Professional & scientific | 2020 |
| Bersey&Simpson Ltd | Wholesale & retail | 2024 |
| Bespoke Automotive Limited | Wholesale & retail | 2013 |
| Best Laser Room Limited | Health & social care | 2017 |
| Better Homes Consultants Limited | Professional & scientific | 2026 |
| Beyond Marathon Limited | Information & communication | 2009 |
| BG Aida Import Export Limited | Wholesale & retail | 2016 |
| BHJ Contractors Limited | Administrative & support | 2014 |
| Bifolds for Builders Ltd | Construction | 2021 |
| Biggleswade Road (Potton) Management Company Limited | Households | 2016 |
| Billgate Limited | Hospitality | 2022 |
| Billieemily Ltd | Wholesale & retail | 2025 |
| Billieemily Properties Ltd | Real estate | 2026 |
| Billing Spring House Management Limited | Households | 2011 |
| Binary Legend Limited | Information & communication | 2022 |
| Binn Consulting Limited | Information & communication | 2004 |
| Bishop Alcock Management Company Limited | Households | 2018 |
| Bishop Meadows Management Company Limited | Households | 2022 |
| Bishops Hampton Limited | Wholesale & retail | 2013 |
| Bishopsgate (Stratford) Management Company Limited | Households | 2004 |
| Bisnonna Associates Ltd | Information & communication | 2024 |
| Bispham Road Management Company Limited | Households | 2025 |
| Bissett's Quality Brickwork Limited | Construction | 2012 |
| Bitcoin SV Ltd | Financial services | 2019 |
| Bitherstone Services Limited | Administrative & support | 1988 |
| BL Property Services Ltd | Administrative & support | 2021 |
| Black Raven Group Limited | Administrative & support | 2018 |
| Blake Homes Limited | Construction | 2025 |
| Blake Renovations Limited | Construction | 2021 |
| Bleecker & 6TH Consultancy Ltd | Professional & scientific | 2024 |
| Blenheim Court Management (Welwyn Garden City) Limited | Administrative & support | 1998 |
| Bleriot Gate Addlestone Management Company Limited | Households | 2015 |
| Bliss Franchise Ltd | Administrative & support | 2022 |
| Blissfulinfinity Limited | Education | 2020 |
| Block Management Cleaning Ltd | Administrative & support | 2020 |
| Bloom Resource London Ltd | Information & communication | 2024 |
| Blossombank (Cannon Lane) Tonbridge Management Company Limited | Households | 2013 |
| Blue Chip Services Limited | Administrative & support | 2018 |
| Blue Content Creators Ltd | Professional & scientific | 2025 |
| Blue Cube Contracting Limited | Construction | 2002 |
| Blue Pilot Plumbing and Heating Ltd | Construction | 2024 |
| Bluetop Lettings Limited | Real estate | 2008 |
| Blythewood Plant Hire Limited | Administrative & support | 2004 |
| BMA Contractors Limited | Construction | 2006 |
| BMA Holdings Group Limited | Financial services | 2024 |
| BO Morgan Film Ltd | Information & communication | 2026 |
| Bolt Shoes Holdings Limited | Wholesale & retail | 2013 |
| Borg Protection Ltd | Financial services | 2024 |
| Boundary (Merton) Management Company Limited | Households | 1986 |
| Bourne Properties Limited | Construction | 2023 |
| Bowden Moss Limited | Construction | 2013 |
| Bowden Property Developments Limited | Construction | 2023 |
| Bowmans Management Limited | Real estate | 2010 |
| Bowron Leathers Limited | Wholesale & retail | 2012 |
| BP Clarke Consultancy Ltd | Professional & scientific | 2025 |
| BPM Electrical Services Limited | Construction | 2021 |
| Bracken Way (Harworth) Management Company Limited | Households | 2007 |
| Bradburns Lane Company Limited | Households | 1988 |
| Braddon & Snow Limited | Professional & scientific | 2008 |
| Braddons TOR Management Company Limited | Households | 2010 |
| Bradley Gardens Management Company Limited | Administrative & support | 2012 |
| Bramley Chase (Jesmond) Management Company Limited | Real estate | 2020 |
| Brampton Lodge Management Company Limited | Households | 1992 |
| Bramshaw Management Company Limited | Households | 2025 |