| Beams Electrical Services Limited | Construction | 2024 |
| Beaneys Abodes Ltd | Real estate | 2025 |
| Beauty at NO. 6 Ltd | Other services | 2020 |
| Bedrock Homes (Hants) Ltd | Construction | 2020 |
| BEE Pilates Ltd | Arts & recreation | 2026 |
| Beechwood Homes (Construction) Limited | Construction | 2007 |
| Beed's Wares Limited | Wholesale & retail | 2021 |
| Bella Healthcare Ltd | Health & social care | 2015 |
| BEN Mason ARB Ltd | Agriculture & fishing | 2022 |
| Bentley Limited | Professional & scientific | 1988 |
| Benton Associates Limited | Financial services | 2009 |
| Benula Limited | Professional & scientific | 1998 |
| Benula Property Ltd | Real estate | 2012 |
| Besideu Ltd | Information & communication | 2025 |
| Bespoke General & Carpentry Services Ltd | Construction | 2014 |
| Bespoke London Spraying Limited | Manufacturing | 2018 |
| Best Finish Decorations Limited | Construction | 2013 |
| Bethlem Allstars Limited | Information & communication | 2008 |
| Big Chat Productions Ltd | Information & communication | 2021 |
| Biohydrogen Technologies Ltd | Professional & scientific | 2022 |
| Bishopbriggs Investments Limited | Construction | 1989 |
| Bishops Flooring Limited | Construction | 2015 |
| Bitten Lemon Ltd | Professional & scientific | 2025 |
| BKD Consulting Ltd | Professional & scientific | 2022 |
| BKG Services Limited | Other services | 2015 |
| Black Dog Heating and Plumbing Limited | Construction | 2014 |
| Black Ghyll Developments Limited | Construction | 2021 |
| Black Harpy Tattoo Ltd | Arts & recreation | 2023 |
| Blackfoot Asset Management Limited | Financial services | 2020 |
| Blackhawk Security Ltd | Administrative & support | 2017 |
| Blackstone Consultancy Ltd | Administrative & support | 2008 |
| Bloom and Belong CIC | Education | 2022 |
| Bloom Global Holdings Limited | Financial services | 2024 |
| Blue Fibre Limited | Construction | 2021 |
| Bluebell LEE Limited | Health & social care | 2014 |
| Blueblooded Medical Limited | Administrative & support | 2013 |
| BM Building and Groundwork's Limited | Construction | 2016 |
| BMP Building Supplies Limited | Wholesale & retail | 2019 |
| BNH Scaffolding Ltd | Construction | 2024 |
| BOC Mann Ltd | Manufacturing | 2026 |
| Bolin Technology Europe Limited | Wholesale & retail | 2023 |
| Books by People Ltd | Information & communication | 2025 |
| Boombox Design Ltd | Professional & scientific | 2018 |
| Botanical Flowers & Events Ltd | Administrative & support | 2020 |
| Boundary I-Media Limited | Information & communication | 2001 |
| Boxchain Moving Ltd | Transport & logistics | 2018 |
| Bracken Gate Management Limited | Households | 2013 |
| Bracken Group Ltd | Professional & scientific | 2019 |
| Brackenwood Residents Company Limited | Households | 1987 |
| Brahma Place Limited | Real estate | 2017 |
| Braids Court Limited | Households | 1989 |
| Brailey's (UK) Ltd | Construction | 1989 |
| Brann New Homes Limited | Construction | 2011 |
| BRH Business Consultants Limited | Professional & scientific | 2016 |
| Briar House Barns Limited | Real estate | 2023 |
| Bridge House Thames Side Ltd | Construction | 2021 |
| Brie Healthcare Ltd | Health & social care | 2026 |
| Brieve Ltd | Extraterritorial | 2025 |
| Bright Crow Ltd | Construction | 2010 |
| Bright N Shiny Oven Cleaners Limited | Administrative & support | 2021 |
| Bright Pursuits Ltd | Real estate | 2024 |
| Brilliant Vision Limited | Information & communication | 2008 |
| Broad BAT Limited | Arts & recreation | 2019 |
| Broadway Property Partnership LLP | | 2020 |
| Brooks & Gill Limited | Construction | 2017 |
| BT and SD Limited | Administrative & support | 2017 |
| Bubbles 'N' Splashes Swim School Limited | Arts & recreation | 2022 |
| Budden Care Ltd | Administrative & support | 2016 |
| Buller Close Owners RTM Company Limited | Households | 2019 |
| Burgess Plant Limited | Construction | 2003 |
| BURGESSB2B Limited | Professional & scientific | 2008 |
| Burwood (Pinner) Limited | Professional & scientific | 1980 |
| Bush Building Services (London) Ltd | Construction | 2022 |
| Business in Vision Limited | Information & communication | 1999 |
| Butterflies Nursery and Preschool Ltd | Education | 2022 |
| Buzz Veterinary Ltd | Professional & scientific | 2019 |
| Bytewave Solutions Limited | Information & communication | 2024 |
| C a Barclay & Co Limited | Construction | 2022 |
| C J Watkins Agricultural Ltd | Agriculture & fishing | 2009 |
| C L Trickett Limited | Manufacturing | 2020 |
| C Solutions (Hellas) Limited | Professional & scientific | 2025 |
| C&K Engineering Solutions Ltd | Professional & scientific | 2026 |
| C.Bromley Plumbing & Heating Limited | Construction | 2015 |
| Cabin Pressure Spirits Ltd | Manufacturing | 2016 |
| Caddy Shack (1997) Limited | Real estate | 1997 |
| Cadet Direct Limited | Wholesale & retail | 1999 |
| Caelum Heating Ltd | Construction | 2024 |
| Calderwood Publishing Limited | Information & communication | 2004 |
| Calico Properties Ltd | Households | 2023 |
| Campbell Munro Investment Management Ltd | Financial services | 2014 |
| Campbell Munro Ltd | Financial services | 1999 |
| Canterbury House Holdings Ltd | Households | 2024 |
| Caprogem Ltd | Professional & scientific | 2018 |
| Cardo Construction Company Limited | Construction | 1987 |
| Cardo Construction Properties Limited | Real estate | 2012 |
| Care ANY Time Limited | Hospitality | 2003 |
| Career Guidance Charts Ltd | Education | 2016 |
| Carol Brazier Sattin Limited | Health & social care | 2023 |
| Carter Tyberghein Limited | Other services | 2006 |
| Carters Boatyard Management Company Limited | Real estate | 2002 |