| Amble GAS Services Limited | Construction | 2012 |
| Amble Harbour Limited | Wholesale & retail | 2012 |
| Amble Men's Shed CIC | Manufacturing | 2025 |
| Amble Quayside Sunday Market Limited | Wholesale & retail | 2012 |
| Amble Scaffolding Ltd. | Administrative & support | 2015 |
| Amble Youth Project Ltd | Health & social care | 2008 |
| Amhse Limited | Other services | 2013 |
| AML Building Services Limited | Construction | 2017 |
| AMP Music Limited | Education | 2024 |
| Amy's Enterprises Ltd | Other services | 2019 |
| Anco Properties Limited | Real estate | 2021 |
| AND Wiser Limited | Health & social care | 2023 |
| Andas Commercial Properties Limited | Financial services | 2021 |
| Andas Property Limited | Real estate | 2016 |
| Anderson Environmental Limited | Professional & scientific | 2015 |
| Andith Properties Limited | Real estate | 2022 |
| ANDRES2025 NCL Ltd | Hospitality | 2025 |
| Andrew J Stewart Ltd | Construction | 2016 |
| Andrew Richardson (Contractor) Limited | Construction | 2005 |
| Andy Chard Ltd | Professional & scientific | 2026 |
| Angel Inked Ltd | Information & communication | 2023 |
| Angela Jayne Auld Limited | Extraterritorial | 2025 |
| Angela Jayne Spark Ltd | Extraterritorial | 2025 |
| Angell Petco (Dogfood) Ltd | Wholesale & retail | 2012 |
| Anograve Limited | Other services | 2017 |
| Apex Health & Fitness Ltd | Arts & recreation | 2017 |
| Apex Improvements Limited | Construction | 2010 |
| Appleby Consulting Limited | Professional & scientific | 1992 |
| Aqua Lettings Ltd | Real estate | 2015 |
| Aquatherm Energy Ltd | Energy | 2025 |
| ARC Kitchens & Bathrooms Limited | Construction | 2011 |
| Arctix Ltd | Wholesale & retail | 2021 |
| Argent Recruit Limited | Information & communication | 2025 |
| Armstrong Contract Services Limited | Construction | 2015 |
| Armstrong Energy Services Limited | Construction | 2016 |
| AS Easy AS Pies Limited | Hospitality | 2021 |
| AS Properties Morpeth Ltd | Real estate | 2024 |
| AS Seen From the Sidecar CIC | Administrative & support | 2017 |
| ASC Haven Estates Ltd | Real estate | 2026 |
| Ascent Solutions Offshore Ltd | Professional & scientific | 2021 |
| Ashburn Financial Consulting Limited | Professional & scientific | 2010 |
| Ashington Autodrome Properties Limited | Real estate | 2011 |
| Ashington Property Solutions Ltd | Real estate | 2019 |
| Aspero Ltd | Professional & scientific | 2023 |
| Aspire Health and Fitness Limited | Arts & recreation | 2018 |
| Assynt Property Group Ltd | Real estate | 2025 |
| Astaway Holidays Ltd | Hospitality | 2021 |
| Astley Livestock Ltd. | Agriculture & fishing | 2012 |
| Aston William Restaurants Ltd | Real estate | 2016 |
| Athey's Moor Airfield Limited | Transport & logistics | 2022 |
| Athey's Moor Flying School Limited | Other services | 2021 |
| Athymetrix Ltd | Administrative & support | 2017 |
| Atkinson Contact Centre Services Limited | Professional & scientific | 2023 |
| Atlas Properties North East Limited | Real estate | 2003 |
| Atomic Audio Ltd | Information & communication | 2023 |
| Atomic Studio Ltd | Information & communication | 2026 |
| Aura Aerospace Ltd | Manufacturing | 2025 |
| Autominster Limited | Wholesale & retail | 1984 |
| Autopod Limited | Wholesale & retail | 2007 |
| Autostrat Ltd | Professional & scientific | 2024 |
| AV Productions Ltd | Arts & recreation | 2020 |
| Avon Umbra Limited | Energy | 2020 |
| AWH Homes Limited | Construction | 2022 |
| Ayre Property Services Limited | Real estate | 2022 |
| B W Wind Turbine Technician Services Ltd | Manufacturing | 2023 |
| Bacmans Community Limited | Education | 2013 |
| Bainbridge Farms Bakery Limited | Manufacturing | 2021 |
| BAL Supermarket Morpeth Limited | Wholesale & retail | 2012 |
| Bamburgh Developments Ltd | Construction | 2024 |
| Bank House Farm Management Co Ltd | Real estate | 2014 |
| Bank House Farm Residents Management Company Limited | Households | 2002 |
| Bar Welding and Fabrication Ltd | Manufacturing | 2025 |
| Barnabas - Safe & Sound | Health & social care | 2002 |
| Barties Developments Ltd | Construction | 2025 |
| Bassu Limited | Other services | 2013 |
| Bastion Associates Limited | Health & social care | 2019 |
| Bay Fencing North East Ltd. | Administrative & support | 2017 |
| Bayfield Design Limited | Professional & scientific | 2011 |
| BE My Business Analyst Ltd | Administrative & support | 2024 |
| Beach Design Limited | Administrative & support | 2002 |
| Bead&Nell Limited | Manufacturing | 2020 |
| Beadnell H & C Management Company Limited | Real estate | 2014 |
| Beal Medical Limited | Health & social care | 2024 |
| Beaney Properties Ltd | Real estate | 2024 |
| Beau Villa Ltd | Real estate | 2020 |
| Beaver Civil Engineering Limited | Construction | 1977 |
| Beckwith Developments Limited | Real estate | 1978 |
| Bede Properties Ltd | Real estate | 2021 |
| Behind the Black Door Limited | Professional & scientific | 2021 |
| Bella Boos Fashion Limited | Wholesale & retail | 2020 |
| Belmont Structural UK Ltd | Construction | 2020 |
| BEN Ormsby Logistics Limited | Transport & logistics | 2025 |
| BEN Robson Builders Limited | Construction | 2022 |
| Bengal Spice (Amble) Ltd | Hospitality | 2017 |
| Bengal Spice Express Amble Ltd | Hospitality | 2026 |
| Benzo & Son’S Trader’S Ltd | Wholesale & retail | 2024 |
| Bespoke Business Support Ltd | Professional & scientific | 2018 |
| Besqu Limited | Professional & scientific | 1993 |
| Best Choice Cottages Ltd | Administrative & support | 2014 |
| Best Kept Secrets Limited | Manufacturing | 1996 |