| Bonnepalm House Management Limited | Households | 1975 |
| Bonusclass Builders Limited | Wholesale & retail | 1989 |
| Book NOW Limited | Information & communication | 1994 |
| Bookham Wine Store Limited | Wholesale & retail | 2010 |
| Boost Software Ltd | Information & communication | 2021 |
| Borderless Atelier Ltd | Arts & recreation | 2026 |
| Borghetto Ltd | Hospitality | 2025 |
| Bork Comms Limited | Other services | 2022 |
| Botnika Organics Ltd | Wholesale & retail | 2023 |
| Bottled Science Ltd | Manufacturing | 2012 |
| Bouncy Apple Ltd | Arts & recreation | 2012 |
| Box Corner Residents Association Limited | Households | 1951 |
| Boxed Triangle Limited | Professional & scientific | 2016 |
| Boxfish Investments Ltd | Professional & scientific | 2020 |
| Bpgd Limited | Professional & scientific | 2007 |
| BPM Bioconsult Ltd | Professional & scientific | 2018 |
| Bradlaw Consulting Ltd | Professional & scientific | 2017 |
| Brain & GUT Limited | Health & social care | 2025 |
| Brand and Copy Limited | Professional & scientific | 2013 |
| Brandfull Limited | Professional & scientific | 2018 |
| Branding 101 Ltd | Professional & scientific | 2024 |
| Brandtrackr Competitive Analytics Limited | Information & communication | 2025 |
| Brandwithsimon Limited | Professional & scientific | 2021 |
| Bray Heavy Industries Ltd | Manufacturing | 2013 |
| Breathing Space (UK) Limited | Construction | 2003 |
| Breezetechuk Ltd | Construction | 2025 |
| Brencro Construction Ltd | Information & communication | 2021 |
| Bretom Limited | Professional & scientific | 2015 |
| Brett Automotive Ltd | Manufacturing | 2025 |
| Brewery Market Ltd | Wholesale & retail | 2017 |
| Brick and MIX Construction Ltd | Construction | 2024 |
| Brick Gallery Limited | Manufacturing | 2019 |
| Brick Rhythm Ltd | Other services | 2026 |
| Bridge Elite Ltd | Professional & scientific | 2021 |
| Bright Space Communications Ltd | Administrative & support | 2020 |
| Brighter Career Limited | Administrative & support | 2020 |
| Brightshade Media Limited | Information & communication | 2009 |
| Brilliant Play Solutions CIC | Arts & recreation | 2014 |
| Brituk Ltd | Wholesale & retail | 2016 |
| Brokkr Consulting and Copywriting Limited | Information & communication | 2022 |
| Brompton Group Ltd | Administrative & support | 2020 |
| Brompton Ltd | Administrative & support | 2016 |
| Brompton Q1.2018 Ltd | Construction | 2018 |
| Brookson (5267H) Limited | Administrative & support | 2007 |
| Brouge Bistros Ltd | Hospitality | 2011 |
| Brula Restaurant Ltd | Hospitality | 2014 |
| Brushpast Limited | Education | 2025 |
| Bryanston Brown Consilium Ltd | Professional & scientific | 2025 |
| Brydges Global Limited | Real estate | 2023 |
| Bso-Fintax Limited | Professional & scientific | 2016 |
| BTC Aviation Ltd | Manufacturing | 2025 |
| Budget Branding UK Ltd | Professional & scientific | 2015 |
| Build Innovations Ltd | Information & communication | 2025 |
| Buildeq Construction Ltd | Construction | 2011 |
| Builder Plus Ltd | Construction | 2018 |
| Building Management Installations Ltd | Wholesale & retail | 1997 |
| Buildmarket Technologies Ltd | Information & communication | 2026 |
| Bujalska Legal Limited | Professional & scientific | 2022 |
| Bukhari-Patterson Limited | Administrative & support | 2007 |
| Bulk BAG IT Limited | Wholesale & retail | 2025 |
| Bulk Bottles Ltd | Wholesale & retail | 2025 |
| Bullmountain Limited | Wholesale & retail | 2023 |
| Buona Fortuna Ltd | Hospitality | 2025 |
| Burchett Wine & Food Marketing Ltd | Professional & scientific | 2025 |
| Burd Express Ltd | Wholesale & retail | 2019 |
| Burgers and Shakes Limited | Hospitality | 2019 |
| Burgersday Limited | Hospitality | 2021 |
| Burn by Tash Ltd | Arts & recreation | 2025 |
| Burtenshaw Group Ltd | Real estate | 2019 |
| Busen Limited | Arts & recreation | 2000 |
| Business Affairs Strategies and Services Limited | Professional & scientific | 2020 |
| Business Building Blocks Ltd | Professional & scientific | 2001 |
| Business Tax & Accounting Solutions Limited | Professional & scientific | 2013 |
| Business Virtue Limited | Information & communication | 2017 |
| Busy Life Music Ltd. | Information & communication | 2018 |
| Butterflies Fashion Boutique Ltd | Wholesale & retail | 2018 |
| Butts Dental Implants Limited | Health & social care | 2013 |
| Buzz Assets Limited | Real estate | 2000 |
| Buzz Consulting Limited | Information & communication | 2022 |
| Buzzy Enterprises Limited | Information & communication | 1973 |
| BY the Wardrobe Ltd | Real estate | 2013 |
| BY YOU Limited | Arts & recreation | 2025 |
| Byrne Leigh Holding Co. Ltd | Financial services | 2023 |
| Byrne Rail Ltd | Administrative & support | 2016 |
| Bytimeproject Ltd | Construction | 2020 |
| C & S Construction Limited | Construction | 2016 |
| C & T Mechanical Services Ltd | Construction | 2020 |
| C a Mccarry Limited | Construction | 2012 |
| C Consultants Limited | Information & communication | 2010 |
| C M Realization Limited | Professional & scientific | 2011 |
| C O'Dwyer Consultants Ltd | Professional & scientific | 2012 |
| C&G Landscapes Ltd | Administrative & support | 2021 |
| C-Squared Consulting Ltd | Professional & scientific | 2008 |
| C.A.E.C.M. Limited | Households | 1985 |
| C.G. & W. Young Limited | Manufacturing | 1974 |
| C.M.A. Hotel Group Limited | Hospitality | 1971 |
| C.M.V.Logistics Limited | Transport & logistics | 2015 |
| C2DEV Limited | Professional & scientific | 2017 |
| C2HL Ltd | Real estate | 2024 |
| Cabal Ltd | Professional & scientific | 2018 |