| APS Compare Ltd | Administrative & support | 2025 |
| Apteka Shop Ltd | Wholesale & retail | 2023 |
| Aqua Ease Ltd | Wholesale & retail | 2020 |
| Aquiatos | Financial services | 2019 |
| Argus Community CIC | Education | 2020 |
| Argus Risk Management Ltd | Administrative & support | 2012 |
| Arlington Care Group Holdings Limited | Administrative & support | 2017 |
| Arlington Care Group Limited | Administrative & support | 2017 |
| Arlington Developments Limited | Construction | 2026 |
| Arlo PA Services Ltd | Administrative & support | 2019 |
| Arm-Spark Electrical Ltd | Construction | 2022 |
| Armand Networks Ltd | Financial services | 2016 |
| Armstrong Safety Consultants Ltd | Professional & scientific | 2021 |
| ARQ Projects Limited | Professional & scientific | 2024 |
| Arthurs Coffee Shop Limited | Hospitality | 2025 |
| Artisan Makers Fair Ltd | Administrative & support | 2025 |
| Arttee Ltd | Arts & recreation | 2025 |
| ASB OIL Ltd | Wholesale & retail | 2025 |
| Asbest + Limited | Professional & scientific | 2025 |
| Asbest Limited | Water & waste | 2023 |
| Asbest Solutions Limited | Professional & scientific | 2025 |
| ASH Electrical Engineering & Contractors Limited | Construction | 2020 |
| ASH Homes (NE) Ltd | Real estate | 2024 |
| ASH Insulation & Contractors Ltd | Construction | 2021 |
| ASH Renewable Energy Ltd | Other services | 2023 |
| Ashby Properties North East Ltd | Real estate | 2026 |
| Ashcroft Projects Limited | Wholesale & retail | 2026 |
| Ashdan Consulting Ltd | Professional & scientific | 2015 |
| Ashdan Estates Ltd | Real estate | 2019 |
| Ashgarth - Products & Assembly Limited | Manufacturing | 2022 |
| Ashgarth Engineering Ltd | Manufacturing | 2017 |
| Ashington Mews Limited | Real estate | 2016 |
| Ashton Wood Equine Transport Ltd | Transport & logistics | 2021 |
| Aspect Voice Limited | Information & communication | 2014 |
| Asset-Form Ltd | Real estate | 2025 |
| Asure Financial Limited | Financial services | 2018 |
| AT and J Communications Limited | Professional & scientific | 1995 |
| Atelier Decor Limited | Wholesale & retail | 2021 |
| Atlas Supply Ltd | Wholesale & retail | 2025 |
| ATM Locksmiths Ltd | Administrative & support | 2023 |
| Atoms Education Community Interest Company | Education | 2019 |
| Attic Creative & Marketing Resource Limited | Professional & scientific | 2015 |
| Aurora Training Limited | Other services | 2007 |
| Austin a Bowman Building Services Limited | Construction | 2025 |
| Automotive Investments Ltd | Administrative & support | 2016 |
| AV Insulation and Plastering Ltd | Construction | 2022 |
| Avalon Warehouse Ltd | Wholesale & retail | 2018 |
| Aventis Group Ltd | Information & communication | 2023 |
| Awty Personnel Ltd | Administrative & support | 2022 |
| AXH Electrical Limited | Construction | 2016 |
| AXH Group Limited | Administrative & support | 2021 |
| Ayres Property Management Limited | Real estate | 2022 |
| Aztec Diamond Equestrian (UK) Limited | Professional & scientific | 2013 |
| Aztec Interiors Ltd | Construction | 2016 |
| Babl Barber Ltd | Other services | 2025 |
| Baby Grows Scan Clinic Limited | Other services | 2021 |
| Bacani Norman Investments Ltd | Financial services | 2025 |
| BAO Asia Ltd | Hospitality | 2026 |
| Barlyn Consulting Limited | Real estate | 2023 |
| Barnacogue Limited | Real estate | 2025 |
| BARRIOS65 Ltd | Administrative & support | 2025 |
| Barron Electrical Services Limited | Construction | 2017 |
| Basewraps Limited | Wholesale & retail | 2017 |
| Beacon Consulting NE Ltd | Professional & scientific | 2026 |
| Beauty Directors Club Ltd | Administrative & support | 2018 |
| BEE Education Ltd | Education | 2021 |
| Believe & BE Ltd. | Education | 2016 |
| Belle Aesthetics Academy Ltd | Education | 2020 |
| Belle Aesthetics and Skin Clinic Ltd | Wholesale & retail | 2023 |
| Bennett Media Ltd | Information & communication | 2025 |
| Bernex UK Limited | Professional & scientific | 1997 |
| Berry NDT (NE) Limited | Professional & scientific | 2016 |
| Bescol Bodyworks Limited | Wholesale & retail | 2020 |
| Bescol Motors (Consett) Limited | Wholesale & retail | 2018 |
| Besr Consett Ltd | Hospitality | 2023 |
| Bestwood Burning Stoves Ltd | Wholesale & retail | 2019 |
| Betinee Limited | Information & communication | 2024 |
| Better Solutions Group Limited | Financial services | 2021 |
| Beyond the Twist Ltd | Wholesale & retail | 2025 |
| BHL Gardening Services Limited | Administrative & support | 2024 |
| BHP Promotions Ltd | Arts & recreation | 2021 |
| Bibby Accounts Limited | Professional & scientific | 2022 |
| Bibby Property Management Limited | Real estate | 2025 |
| Bibby Property Solutions Limited | Construction | 2017 |
| Bibby Racing Limited | Arts & recreation | 2025 |
| Bibby Residential Limited | Real estate | 2021 |
| Big Hands Little Hands Childcare Limited | Health & social care | 2015 |
| Biotoolomics Limited | Manufacturing | 2005 |
| Bird Cycleworks Ltd | Manufacturing | 2013 |
| BITS4BIKES Limited | Wholesale & retail | 2010 |
| Black and White BOY Limited | Professional & scientific | 2017 |
| Blackfyne FC Ltd | Arts & recreation | 2026 |
| Blackhill Takeway Ltd | Hospitality | 2025 |
| Bladeworks Wind Services Ltd | Construction | 2026 |
| Blanchland Community Development Organisation Ltd | Other services | 2006 |
| Blast Away JET Washing Consett Ltd | Administrative & support | 2025 |
| Bles Professionals Ltd | Administrative & support | 2021 |
| Bles Properties Ltd | Real estate | 2025 |
| Bloc Pictures Limited | Information & communication | 2021 |
| Blue Square Risk Management Ltd | Administrative & support | 2026 |