| 13/14 Haugh Lane Limited | Households | 1997 |
| A & R Scaffolding and Groundwork Limited | Construction | 1999 |
| A a Jewitt and Sons Limited | Transport & logistics | 2005 |
| A-Belco Industrial Accessories Limited | Professional & scientific | 1990 |
| A.C. 2000 (UK) Limited | Professional & scientific | 1999 |
| A.F.I. Limited | Administrative & support | 1990 |
| Aaf-Mcquay UK Limited | Professional & scientific | 1988 |
| Accounting Plus Limited | Professional & scientific | 1995 |
| AD Gefrin Distillery Limited | Manufacturing | 2018 |
| AD Gefrin LLP | | 2018 |
| Adeline's Hairdressing Limited | Other services | 2002 |
| Admiral Collingwood Court (Block 1) Limited | Households | 2024 |
| Adrian Sander Furniture Limited | Manufacturing | 2003 |
| Advance Northumberland (Commercial) Limited | Real estate | 1998 |
| Advance Northumberland (Developments) Limited | Construction | 2011 |
| Advance Northumberland (Housing) Limited | Real estate | 1986 |
| Advance Northumberland (Projects) Ltd | Construction | 2011 |
| Advanced Automotive Systems Limited | Manufacturing | 2003 |
| Aerobic Technologies Limited | Wholesale & retail | 2016 |
| Agma Limited | Manufacturing | 1968 |
| Agrifood Technical Services Limited | Professional & scientific | 2013 |
| Air Images Limited | Professional & scientific | 2002 |
| Alan Barrett Limited | Wholesale & retail | 2002 |
| Albury Estate Fisheries (2008) Limited | Agriculture & fishing | 2008 |
| Allen Consultant Engineering Limited | Professional & scientific | 1993 |
| Alnmouth Golf Club.Limited(The) | Arts & recreation | 1930 |
| Alnwick District Playhouse Trust | Hospitality | 1990 |
| Amcara Ltd | Agriculture & fishing | 2004 |
| Andrew Coulson Property Sales & Lettings Limited | Real estate | 1989 |
| Anya International Limited | Professional & scientific | 2006 |
| Applied Dataflow Research Limited | Information & communication | 1999 |
| Arbanmore Ltd. | Agriculture & fishing | 2016 |
| Arcot Grange Limited | Households | 2015 |
| Arcot Hall Golf Club Limited | Arts & recreation | 1909 |
| Arlo Cafe Ltd | Hospitality | 2026 |
| Armstrong Farming Ltd | Administrative & support | 2003 |
| Arrow Construction Equipment Limited | | 1965 |
| Artneat Limited | Real estate | 1989 |
| Ashley Matthews Limited | Wholesale & retail | 2005 |
| Astor & Carroll | | 1990 |
| Atlas Associates (UK) Ltd | Professional & scientific | 2004 |
| Atlas Garages (Morpeth) Limited | Wholesale & retail | 1990 |
| Autocare (North East) Limited | Wholesale & retail | 2006 |
| Azure Garden Centre Limited | Wholesale & retail | 1992 |
| B. Mason (Tractors) Limited | Wholesale & retail | 2003 |
| B.H.P. (Norham) Limited | Wholesale & retail | 2002 |
| Bainbridge Farms Cottages Limited | Hospitality | 2020 |
| Banner Seafoods Limited | | 1980 |
| Barry Nelson Roofing Services Limited | Construction | 2002 |
| Barter Books Holdings Limited | Wholesale & retail | 2018 |
| Bbgb Limited | Real estate | 2025 |
| Beauclerc Investments Limited | Real estate | 2004 |
| Becks Hospitality Limited | Professional & scientific | 2025 |
| Bedlington Development Company Limited | Wholesale & retail | 2003 |
| Bedlington MOT and Service Centre Ltd | Wholesale & retail | 2022 |
| Bedmax Limited | Manufacturing | 1999 |
| Bell View (Belford) | Health & social care | 1998 |
| Bell View Care Limited | Health & social care | 2008 |
| Berwick-Upon-Tweed Preservation Trust | Arts & recreation | 1985 |
| Big Pine Trail Ltd | Extraterritorial | 2022 |
| Billy Nomates Limited | Arts & recreation | 2004 |
| Bishops Garages Limited | Wholesale & retail | 1956 |
| Blindburn Assets Limited | Financial services | 2019 |
| Blooming Happy Training Ltd | Education | 2020 |
| Blyth Healthcare Limited | Wholesale & retail | 2024 |
| Blyth Valley Consultants Ltd | Wholesale & retail | 1999 |
| BM Prudhoe Limited | Manufacturing | 2026 |
| Bodyworks Beauty & Wellness Ltd | Other services | 2025 |
| Bradleys Master Locksmiths Ltd | Construction | 1954 |
| Brambles Childcare Centre Ltd | Education | 2003 |
| Bridal Wish Ltd | Wholesale & retail | 2006 |
| British Agriculture Marketing Limited | Professional & scientific | 2003 |
| Britton Leisure Limited | Hospitality | 1980 |
| Brocksbushes Limited | Wholesale & retail | 2000 |
| Brunskill and Loveday Limited | Arts & recreation | 2005 |
| Burdus Ltd | Professional & scientific | 2003 |
| Burgham Management Company Limited | Households | 2023 |
| Burn Brae Care Limited | Health & social care | 1994 |
| Burncastle Farming Company Ltd | Agriculture & fishing | 1996 |
| Burradon Farm Houses and Cottages Limited | Hospitality | 2007 |
| Business Dynamic Solutions Limited | Professional & scientific | 2005 |
| C & B Properties North East Limited | Real estate | 2022 |
| C & W Groundworks Limited | Construction | 2004 |
| C G Joinery and Building Limited | Administrative & support | 2017 |
| C S Brindley Limited | Professional & scientific | 2007 |
| C. Mclaren Limited | Construction | 2003 |
| Cablebright Limited | Manufacturing | 1999 |
| Camico Ltd. | Manufacturing | 1999 |
| Candova Ltd | Hospitality | 2004 |
| Carltons the Feed Merchants Limited | Wholesale & retail | 2007 |
| Casencia Limited | Manufacturing | 2005 |
| Caskflasks Limited | Extraterritorial | 2002 |
| Cassie Woods Limited | Agriculture & fishing | 2004 |
| Castle Carpets (Morpeth) Ltd | Wholesale & retail | 2006 |
| Catalize Limited | Information & communication | 2002 |
| Cavendish Motor Co. Limited | Wholesale & retail | 2001 |
| CCF (NE) Limited | Other services | 2008 |
| Cereal Foods Limited | Wholesale & retail | 2000 |
| Cgyl Consulting Limited | Administrative & support | 2012 |
| Cheswick Inns Limited | Hospitality | 2006 |