| Bench HUT Design and Print Limited | Other services | 2010 |
| Bendkowski Trans Ltd | Transport & logistics | 2024 |
| Benjamin Albert Limited | Professional & scientific | 2025 |
| Bensham 17 Ltd | Professional & scientific | 2017 |
| Benson Wood (Darlington) Limited | Professional & scientific | 2009 |
| Berfreron Limited | Real estate | 2024 |
| Berkeley Square Capital Limited | Professional & scientific | 2002 |
| Berkley PCA Property Services Limited | Professional & scientific | 2017 |
| Bespoke Denture Clinic Ltd | Health & social care | 2012 |
| Bespoke DRY Cleaners Limited | Other services | 2017 |
| Bespoke Windows Darlington Limited | Construction | 2016 |
| Best Afro Foods Ltd | Wholesale & retail | 2023 |
| Best Kebab & Grill Ltd | Hospitality | 2026 |
| Best Kebab 1 Ltd | Hospitality | 2025 |
| Best One Mini Market DL1 Limited | Wholesale & retail | 2026 |
| Best One SAM Barbers Ltd | Other services | 2023 |
| Best One Tryes & Services Ltd | Wholesale & retail | 2026 |
| Best Process Services Limited | Professional & scientific | 2012 |
| Best Supermarket D Ltd | Wholesale & retail | 2024 |
| Bestbark Limited | Wholesale & retail | 2024 |
| Beta North Limited | Health & social care | 2012 |
| Beth at IVY House Limited | Other services | 2022 |
| Better ALL Round Ltd | Manufacturing | 2012 |
| Bevan VAT Consultancy Limited | Professional & scientific | 2018 |
| Bex's Bodacious Breaks Ltd | Administrative & support | 2025 |
| Bexbrides Ltd | Wholesale & retail | 2019 |
| Beyond Renovations NE Ltd | Extraterritorial | 2024 |
| Bggc Trading Limited | Arts & recreation | 2016 |
| BH & J Ltd | Real estate | 2015 |
| BH a Subco Limited | Health & social care | 2026 |
| BH Blinds & Shutters Ltd | Construction | 2024 |
| BH Consultants and Project Management Ltd | Construction | 2018 |
| BH Holdings Global Limited | Other services | 2024 |
| BH OM Subco Limited | Health & social care | 2026 |
| BH Project Management Limited | Construction | 2020 |
| BH Projects Group Limited | Construction | 2003 |
| BH RL Subco Limited | Health & social care | 2026 |
| Bhadar Singh Engineering and C.I. Limited | Professional & scientific | 2024 |
| Bhangu Residentials Limited | Households | 2025 |
| BHP Coaching Ltd | Professional & scientific | 2020 |
| BHP Home Limited | Real estate | 2007 |
| BHP Law Limited | Professional & scientific | 2025 |
| BIC Automotive Solutions Ltd | Wholesale & retail | 2023 |
| Bicycle Bearings Ltd | Wholesale & retail | 2022 |
| Big Bird Limited | Professional & scientific | 2014 |
| Big Bite Pizza 4U Limited | Hospitality | 2024 |
| Big FAT Media Limited | Professional & scientific | 2017 |
| Big Fridge Limited | Administrative & support | 2013 |
| Big Jim's BUS Shed Ltd | Transport & logistics | 2023 |
| Big Little Fish Limited | Information & communication | 2009 |
| Big MAN Cards Ltd | Wholesale & retail | 2025 |
| Bightvolt Ltd | Information & communication | 2025 |
| Bignall Group Ltd | Manufacturing | 1976 |
| Billau Motorcycles Limited | Wholesale & retail | 2021 |
| Billy Mulholland Decking & Verandas Ltd | Construction | 2024 |
| Bilsdale Homes Limited | Construction | 2024 |
| Bimteck Ltd | Wholesale & retail | 2024 |
| Binos Pizzeria Ltd | Hospitality | 2025 |
| Binzruz Aquatek Ltd | Manufacturing | 2021 |
| Binzruz Limited | Administrative & support | 2017 |
| Bion Limited | Information & communication | 2019 |
| Bionic Mosquito Limited | Manufacturing | 2025 |
| Birds Prestige Cars Ltd | Professional & scientific | 2024 |
| Birkson Limited | Real estate | 1999 |
| Birria Street Kitchen Limited | Hospitality | 2026 |
| Birsay Creative Limited | Professional & scientific | 2023 |
| Bishop Hogarth Catholic Education Trust | Education | 2011 |
| Bishop Hogarth Services Limited | Education | 2012 |
| Bismi Retail Limited | Wholesale & retail | 2018 |
| Biso RU Ceylon Ltd | Other services | 2026 |
| Bison Security Services Ltd | Administrative & support | 2025 |
| Bison Services Ltd | Administrative & support | 2025 |
| Bitformed Ltd | Information & communication | 2010 |
| BJ Upholstery Ltd | Other services | 2020 |
| BK Commercial Flooring Ltd | Construction | 2024 |
| BK Newcastle Ltd | Arts & recreation | 2022 |
| BL Chisholm Logistics Ltd | Transport & logistics | 2025 |
| Black and White Investments | Financial services | 2014 |
| Black Olive Deli Limited | Hospitality | 2015 |
| Black Rose Collective Ltd | Wholesale & retail | 2026 |
| Blackart Composites Limited | Administrative & support | 2024 |
| Blackbird Creative Arts Ltd | Arts & recreation | 2019 |
| Blackburn Marshall Construction (NE) Limited | Construction | 2011 |
| Blackett Hart & Pratt LLP | | 2006 |
| Blackstone Properties NE Ltd | Real estate | 2021 |
| Blackthorn Estates Ltd | Real estate | 2025 |
| Blackwell Consulting (DL3) Limited | Professional & scientific | 2026 |
| Blackwell Grange Golf Club Limited | Arts & recreation | 1964 |
| Blackwell Heating & Plumbing Ltd | Construction | 2007 |
| Blackwell Investments (NE) Ltd. | Construction | 2013 |
| Blackwell Trading Ltd | Wholesale & retail | 2025 |
| Bladestar Renewables Ltd | Manufacturing | 2019 |
| Blaeford Richardson (Darlington) Ltd | Professional & scientific | 2014 |
| Blake Newport Associates Limited | Professional & scientific | 1991 |
| Blake Telecom Ltd | Information & communication | 2018 |
| Blakebun Limited | Wholesale & retail | 2025 |
| Blakelock Million Ltd | Construction | 2020 |
| Blaxx Ltd | Manufacturing | 2024 |
| Bliss Financial Solutions Ltd | Financial services | 2019 |
| Blockchain Digital Gold Trading LLC Ltd | Manufacturing | 2012 |