| 102 Beccles Road Limited | Households | 2022 |
| 13J Ltd | Construction | 2020 |
| 17-18 Middle Market Road Limited | Real estate | 2022 |
| 194-196 Brigstock Road Limited | Households | 2014 |
| 1A Belinda Road RTM Company Limited | Real estate | 2011 |
| 360 @ Alexandra Interiors Ltd | Wholesale & retail | 2020 |
| 3FARM Honey Limited | Agriculture & fishing | 2025 |
| 49 Eastborough Limited | Households | 2020 |
| 5 Dolphin Point Ltd | Hospitality | 2024 |
| 77 London Street Management Company Limited | Real estate | 2019 |
| 8 Ball Direct Ltd | Manufacturing | 2020 |
| 8 Ball Leisure Ltd | Administrative & support | 2018 |
| 98 Roofing Services Ltd | Construction | 2022 |
| A & a Leisure Vehicles Ltd | Administrative & support | 2024 |
| A & C Engineering & Construction Limited | Manufacturing | 2016 |
| A & L Brewis Properties Ltd | Real estate | 2026 |
| A K Domestic Appliances Ltd. | Other services | 2010 |
| A M Pringle Property Limited | Real estate | 2025 |
| A Sibley Ltd | Extraterritorial | 2018 |
| A.Y. Developments Limited | Professional & scientific | 2013 |
| A1 Fire Stopping and Drilling Services Ltd | Construction | 2016 |
| A1 Kennels and Cattery Limited | Other services | 2002 |
| A1 MOT Centre Limited | Wholesale & retail | 2009 |
| A1 MOT Centre NE Ltd | Wholesale & retail | 2021 |
| AAC Leisure Limited | Wholesale & retail | 2005 |
| Aavid Thermalloy UK Ltd | Financial services | 1999 |
| AC Electrical Specialists Ltd | Construction | 2012 |
| Acorns (Ashington) Limited | Health & social care | 2024 |
| AD94 Ltd | Wholesale & retail | 2026 |
| Adams Mind Body Strength Ltd | Other services | 2025 |
| Advance Garage Equipment Ltd | Wholesale & retail | 2015 |
| Advance Green Futures Limited | Professional & scientific | 2025 |
| Advance Manor Walks Limited | Real estate | 2025 |
| Advance Northumberland Limited | Professional & scientific | 2018 |
| Advanced Office Solutions Ltd | Administrative & support | 2023 |
| AEJ Property Group Ltd | Real estate | 2023 |
| Aero Forge Renewables Ltd | Professional & scientific | 2026 |
| Aero Moss Consulting Ltd | Professional & scientific | 2011 |
| AEY Grading Ltd | Professional & scientific | 2025 |
| AFR Clean-Ex Ltd | Administrative & support | 2009 |
| AFY Properties Limited | Real estate | 2023 |
| AGE UK Northumberland | Health & social care | 1998 |
| AGE UK Northumberland Trading Limited | Hospitality | 1999 |
| Aggies Fitness Ltd | Arts & recreation | 2025 |
| Aggies Pizza Ltd | Hospitality | 2025 |
| Aggies Pizza NE Ltd | Hospitality | 2024 |
| Ahrl NE Investments Ltd | Hospitality | 2018 |
| Ahrl NE Services Ltd | Real estate | 2021 |
| AI Angling Ltd | Information & communication | 2026 |
| AI Hub Technologies Limited | Information & communication | 2025 |
| AJ Glazing Ltd | Construction | 2019 |
| AK Bajwa and Brothers Ltd | Wholesale & retail | 2023 |
| Aleenas Peri Peri Ltd | Hospitality | 2017 |
| Alex Mann Solutions Limited | Real estate | 2015 |
| Alex Scougal Bolting Services Ltd | Manufacturing | 2019 |
| Alexandra Interiors (Ashington) Limited | Transport & logistics | 2012 |
| Alexandra Interiors Limited | Manufacturing | 2009 |
| Alexandra Interiors the Factory Ltd | Manufacturing | 2020 |
| Alexandra Interiors the Hub Ltd | Manufacturing | 2020 |
| ALI Barbers AB Ltd | Other services | 2025 |
| ALI Berber Ltd | Other services | 2025 |
| Allerburn Manor (Alnwick) Management Company Limited | Households | 2023 |
| Allsopp & Allsopp Ltd | Financial services | 2023 |
| Alluvion Home Ltd | Wholesale & retail | 2020 |
| ALS Property Investment Ltd | Real estate | 2023 |
| Alspeed Motorcycles Ltd | Wholesale & retail | 2019 |
| Alyn Brewis Limited | Wholesale & retail | 2023 |
| AM Properties (Bedlington) Ltd | Real estate | 2010 |
| AMA Healthcare Limited | Other services | 2006 |
| Amanah Property Consultants Limited | Administrative & support | 2008 |
| AME Building Contractors Ltd | Construction | 2013 |
| Ameera's Eatery Ltd | Hospitality | 2017 |
| AMR Professional Hairdressing Ltd | Other services | 2025 |
| AN NAM Kitchen Ltd | Hospitality | 2025 |
| Andy Cooper Developments Ltd | Real estate | 2020 |
| Andy Cooper Limited | Construction | 2014 |
| Another Spud Morpeth Ltd | Hospitality | 2024 |
| Anthony's Autos Ltd | Wholesale & retail | 2024 |
| Apex Suspended Ceilings and Partitions Limited | Construction | 2017 |
| Appleby Environmental Services Limited | Agriculture & fishing | 2008 |
| Appleton at Southside Ltd | Real estate | 2020 |
| Applewood Childcare Limited | Health & social care | 2025 |
| Arcgroup SPV 1 Ltd | Financial services | 2025 |
| Arch Engineering Limited | Professional & scientific | 2023 |
| Arch Group Ltd | Real estate | 2023 |
| Archiemorpslife Ltd | Extraterritorial | 2024 |
| Ardour Surface Design Ltd | Construction | 2022 |
| Arian EMS Limited | Manufacturing | 2017 |
| Armanete Ltd | Real estate | 2024 |
| ARP Property Services Limited | Financial services | 2018 |
| Arrow Creative Communications Limited | Professional & scientific | 2016 |
| Arukah Homes Limited | Real estate | 2025 |
| AS Joinery & Maintenance Ltd | Construction | 2026 |
| ASC Housing and Property Ltd | Real estate | 2022 |
| Ashington Association Football Club Limited | Arts & recreation | 2019 |
| Ashington Autodrome Limited | Wholesale & retail | 2002 |
| Ashington Car Valeting & Detailing Services Ltd | Wholesale & retail | 2022 |
| Ashington Caravans & Storage Limited | Extraterritorial | 2011 |
| Ashington Central Limited | Health & social care | 2007 |
| Ashington Community Development Group Ltd | Hospitality | 2025 |