| Beyondly Ltd | Wholesale & retail | 2025 |
| Bezt Consulting Limited | Construction | 2021 |
| Bfamily Limited | Hospitality | 2024 |
| BG Heating Services Limited | Construction | 2015 |
| BG Lofts and Extensions Ltd | Construction | 2019 |
| BG Solutions Ltd | Information & communication | 2006 |
| BGB Brickwork and Construction Ltd | Construction | 2021 |
| BGS Investments LLP | | 2012 |
| BH M & E Surveying Ltd | Administrative & support | 2021 |
| BH Thermal Solutions Limited | Construction | 2025 |
| Bhadra's Ultrasound Limited | Professional & scientific | 2024 |
| Bhaja Govindam Ltd | Administrative & support | 2024 |
| Bhama Properties Limited | Real estate | 2022 |
| Bhasin Properties Ltd | Real estate | 2020 |
| Bhella Homes Ltd | Construction | 2020 |
| Bhella R Clinical Services Ltd | Health & social care | 2017 |
| Bhinder's Ltd | Wholesale & retail | 2022 |
| BHP Mechanical Services Ltd | Construction | 2015 |
| Bhullar Optics Limited | Health & social care | 2018 |
| BI Ventures Limited | Wholesale & retail | 2023 |
| Bibo Solutions LLP | | 2012 |
| Bice Energy Limited | Energy | 2023 |
| Bicknell Transport Ltd | Transport & logistics | 2020 |
| Biddenden Bakehouse Limited | Wholesale & retail | 2014 |
| Biddenden Family Chiropractic Limited | Professional & scientific | 2017 |
| Bieno Restaurant Ltd | Hospitality | 2024 |
| Big Babu JI Ltd | Wholesale & retail | 2025 |
| Big Boss Caravan Ltd | Hospitality | 2026 |
| Big Boss Group Ltd | Transport & logistics | 2026 |
| Big Boys Kent Ltd | Hospitality | 2024 |
| Big Green Snake Ltd | Information & communication | 2022 |
| Big-D SET Construction Limited | Manufacturing | 2020 |
| Bigatmosphere Limited | Wholesale & retail | 2006 |
| Bigfoot Basketball Ltd | Wholesale & retail | 2009 |
| Biggins Wood Management Company Limited | Real estate | 2025 |
| Bigjigs Toys Limited | Manufacturing | 2003 |
| Bignell-Howse Trading Ltd | Construction | 2019 |
| Bigtekuk Ltd | Wholesale & retail | 2021 |
| Bijral & Co Limited | Health & social care | 2021 |
| Bill Dane Property Sales Ltd | Real estate | 2020 |
| Bill Hosking Limited | Professional & scientific | 2014 |
| Bilsington Therapeutic Stables CIC | Health & social care | 2015 |
| Bilt. Building Merchants Ltd | Wholesale & retail | 2019 |
| Bilting Farm Limited | Other services | 2013 |
| Bing Bling Cleaning Services Ltd | Administrative & support | 2012 |
| Bingle Limited | Real estate | 2020 |
| BIO Pathica Limited | Wholesale & retail | 1996 |
| BIO QC Ltd | Professional & scientific | 2024 |
| BIO Resolutions EOT Ltd | Professional & scientific | 2024 |
| BIO Resolutions Limited | Financial services | 2024 |
| Biobest UK Limited | Administrative & support | 2015 |
| Biodiversity and Habitat Solutions Limited | Agriculture & fishing | 2023 |
| Biomark Forensics Limited | Other services | 2006 |
| Biomed Insights Limited | Professional & scientific | 2015 |
| Bioprocess Engineering Services Limited | Administrative & support | 1996 |
| BIR Transportation Ltd | Transport & logistics | 2025 |
| Birch Pilates Ltd | Arts & recreation | 2026 |
| Birch Plant Hire Limited | Construction | 1992 |
| Birchdale Installations Limited | Construction | 2012 |
| Birchmore Accountants Ltd | Professional & scientific | 2025 |
| Bird Projects Ltd | Professional & scientific | 2016 |
| Bird Property Maintenance Limited | Construction | 2022 |
| Birth Actually Ltd | Health & social care | 2022 |
| Biscuit's Tearoom Limited | Hospitality | 2013 |
| Bishay Media Limited | Information & communication | 2017 |
| Bishnat Limited | Hospitality | 2023 |
| Bishnu Property Ltd | Real estate | 2021 |
| Bishop Co Tech Limited | Professional & scientific | 2025 |
| Bishop Project Management Services Limited | Administrative & support | 2003 |
| Bishopsdale Village Community Interest Company | Information & communication | 2020 |
| Bison Court Residents Association Limited | Households | 1991 |
| Bison Manoeuvres Ltd | Arts & recreation | 2013 |
| Bite Rite Limited | Real estate | 2025 |
| Bite Shopping Limited | Wholesale & retail | 2024 |
| BIZ Efficiency Ltd | Wholesale & retail | 2025 |
| BIZ Key Solution Ltd | Professional & scientific | 2023 |
| Bizcoin Reporter Ltd | Information & communication | 2021 |
| Bizibit Ltd | Information & communication | 2015 |
| Biziwazi Limited | Health & social care | 2021 |
| Bizready CIC | Education | 2023 |
| BJ Cleaning Services Limited | Administrative & support | 2025 |
| BJ Cunningham Limited | Professional & scientific | 2001 |
| BJA Civil Consulting Limited | Construction | 2010 |
| BJB Utilities Ltd | Construction | 2015 |
| BJG Roofing Limited | Construction | 2023 |
| BK CAD MAN Ltd | Professional & scientific | 2016 |
| Bkem Consults Limited | Professional & scientific | 2025 |
| BKF Capital Limited | Wholesale & retail | 2022 |
| BKG Private Hire Ltd | Transport & logistics | 2024 |
| Black & White Estates Ltd | Real estate | 2009 |
| Black Barn Works Limited | Information & communication | 2026 |
| Black Constructions Limited | Construction | 1995 |
| Black Diamond Performance Limited | Wholesale & retail | 2001 |
| Black Dog Sets Ltd | Administrative & support | 2019 |
| Black Stallion Group Limited | Hospitality | 2024 |
| Black Stallion Inns Limited | Hospitality | 2024 |
| Black Vault Digital Ltd | Other services | 2018 |
| Blackline Automotive Ltd | Wholesale & retail | 2025 |
| Blackline Capital Limited | Real estate | 2015 |
| Blackline PH Ltd | Transport & logistics | 2024 |