| Ava&Archie Estates Ltd | Real estate | 2024 |
| Avalon Direct Ltd | Wholesale & retail | 2025 |
| Avance Automotive Limited | Wholesale & retail | 2022 |
| AVE Integrated Health Care Limited | Administrative & support | 2024 |
| Awesome Media Publications Limited | Information & communication | 2017 |
| Axe-Aholics AXE Throwing Ltd | Arts & recreation | 2026 |
| Aycliffe Auto Supplies Limited | Wholesale & retail | 2012 |
| Aycliffe Autos Limited | Wholesale & retail | 2012 |
| Aycliffe Dairy Limited | Wholesale & retail | 2017 |
| Aycliffe Dance Academy Limited | Arts & recreation | 2011 |
| Aycliffe Engineering Limited | Manufacturing | 1947 |
| Aycliffe Fabrications Limited | Manufacturing | 2001 |
| Aycliffe Fire Test Facility Limited | Professional & scientific | 1990 |
| Aycliffe Homes Limited | Real estate | 2019 |
| Aycliffe MOT Testing Centre Ltd | Professional & scientific | 2012 |
| Aycliffe Nexus CIC | Education | 2026 |
| Aycliffe Pizza Ltd | Hospitality | 2025 |
| Aycliffe Property Ltd | Real estate | 2021 |
| Aycliffe Radio CIC | Information & communication | 2018 |
| Aycliffe Self Storage Limited | Administrative & support | 2008 |
| Aycliffe Trade 'N' Save Limited | Professional & scientific | 2000 |
| Ayclive C.I.C. | Arts & recreation | 2024 |
| Ayclive Events Limited | Arts & recreation | 2023 |
| B Postle Limited | Construction | 2013 |
| B.A. March Construction Limited | Construction | 2019 |
| B.C. Stewart Limited | Construction | 1988 |
| Baby Biography Limited | Manufacturing | 2013 |
| Bagshaw Safety Solutions Ltd | Professional & scientific | 2024 |
| Bahmanizad Limited | Hospitality | 2020 |
| Balefire Ltd | Manufacturing | 2021 |
| Baltic Recruitment Services Limited | Administrative & support | 2006 |
| Barbara ANN Limited | Wholesale & retail | 2025 |
| Bargain Buys Retail Limited | Wholesale & retail | 2004 |
| Barker Protection Services Ltd | Administrative & support | 2026 |
| Bass GAS Services Limited | Professional & scientific | 2017 |
| BCS Render Systems Limited | Construction | 2014 |
| BD Spice (Aycliffe) Ltd | Hospitality | 2023 |
| Beakon Consultancy Limited | Professional & scientific | 2020 |
| Becla Engineering Ltd | Professional & scientific | 2022 |
| Beechfield Properties Community Interest Company | Health & social care | 2009 |
| Belgrave Lighting Ltd | Manufacturing | 2026 |
| Believe Carlton MSG LLP | | 2022 |
| Believe Carlton Witton LLP | | 2023 |
| Belifted Social Work Limited | Health & social care | 2023 |
| Bengal Lounge Curry Ltd | Hospitality | 2022 |
| Bengal Lounge Woodham Ltd | Hospitality | 2018 |
| Bensiri Consultancy Services Ltd. | Professional & scientific | 2017 |
| Berenco Limited | Other services | 2013 |
| Bernini Natural Stone Limited | Construction | 2011 |
| Bespoke Interior Solutions NE Ltd | Construction | 2024 |
| Best Fast Food (NE) Ltd | Hospitality | 2025 |
| Better Brothers Community Interest Company | Arts & recreation | 2024 |
| Beyondstudio Limited | Professional & scientific | 2026 |
| BID to Differ Procurement Services Ltd | Professional & scientific | 2025 |
| Biedra Limited | Wholesale & retail | 2025 |
| BLA Holdings Limited | Financial services | 2021 |
| BLA Properties Limited | Real estate | 2021 |
| Black Building Solutions Ltd | Construction | 2019 |
| Black Oak Construction Limited | Construction | 2026 |
| Black PAW Ltd | Households | 2025 |
| Blacketts of Butterknowle Limited | Financial services | 2019 |
| Blackwell Architectural Services Limited | Professional & scientific | 2023 |
| Blazeyg Consultancy Services Ltd | Public administration | 2024 |
| Blinkr Digital Ltd | Professional & scientific | 2025 |
| Body Extreme Limited | Wholesale & retail | 2009 |
| Bodyworks Beauty Therapy Limited | Other services | 2005 |
| Bohdify Limited | Wholesale & retail | 2025 |
| Bonomi NE Ltd | Hospitality | 2019 |
| Boom.Furniture Ltd | Wholesale & retail | 2023 |
| BPJ Draughting Limited | Professional & scientific | 2019 |
| BR Automotive Ltd | Financial services | 2019 |
| Bradley Moorhouse Associates Limited | Professional & scientific | 2014 |
| Bradley Paper Converters Limited | Manufacturing | 2014 |
| Bremner Brown Carpentry Limited | Construction | 2012 |
| Bricks and Morton Ltd | Real estate | 2024 |
| Bright Futures Trust C.I.C. | Education | 2015 |
| Britgrocer International Holdings Ltd | Financial services | 2015 |
| Britgrocer Ltd | Wholesale & retail | 2015 |
| Bro's Barberz Ltd | Other services | 2025 |
| BTS Fabrications Limited | Manufacturing | 2006 |
| BTS Facades and Fabrications Holdings Limited | Financial services | 2025 |
| Buckley Holdings NE Limited | Financial services | 2026 |
| Buona Forchetta Limited | Hospitality | 2020 |
| Burnynghill Holdings Limited | Administrative & support | 2011 |
| Business Finance Market Ltd | Information & communication | 2019 |
| C & a Developers Limited | Construction | 2005 |
| C & a Matthews Limited | Administrative & support | 2008 |
| C & D Learning Solutions Limited | Professional & scientific | 2015 |
| C D M Production Services Ltd | Professional & scientific | 2022 |
| C Dent Roofing Limited | Construction | 2015 |
| C F Decorating Limited | Other services | 2019 |
| C R Atkinson & Sons Limited | Manufacturing | 2002 |
| C S (Northern) Ltd | Manufacturing | 2014 |
| C&A Embroidery and Print Ltd | Manufacturing | 2019 |
| C&M Properties (NE) Limited | Real estate | 2019 |
| C&M Sheeting & Cladding Ltd | Construction | 2018 |
| C.G. Fixings Limited | Wholesale & retail | 2003 |
| Cabe Property Limited | Real estate | 2013 |
| Cadsphere Ltd | Construction | 2011 |
| Cam-Tec Systems Limited | Administrative & support | 1992 |