| AKK 2025 Ltd | Wholesale & retail | 2025 |
| Aktar Sisters Ltd | Wholesale & retail | 2024 |
| AL Ahmed CXT Limited | Wholesale & retail | 2024 |
| Alan Skinner Limited | Manufacturing | 2012 |
| Alansway Consultants Limited | Professional & scientific | 2017 |
| Alectec Ltd | Professional & scientific | 2012 |
| Alexander Carrs Ltd | Transport & logistics | 2025 |
| Alfies Events Catering Ltd | Hospitality | 2017 |
| ALI Barber NE Ltd | Other services | 2023 |
| ALL Clean NE Ltd | Administrative & support | 2017 |
| ALL Star Productions (NE) Ltd | Information & communication | 2012 |
| ALL Star Studios CIC | Arts & recreation | 2020 |
| ALL Water Aquatics Ltd | Wholesale & retail | 2024 |
| All-Temps Recruitment Limited | Administrative & support | 2000 |
| Alle Barber Limited | Other services | 2025 |
| Alnwick Welding Ltd | Manufacturing | 2016 |
| Alof Ltd | Arts & recreation | 2023 |
| Alpha Paints Limited | Wholesale & retail | 2011 |
| ALS Pest Solutions Limited | Professional & scientific | 2017 |
| Alticore Access Ltd | Professional & scientific | 2026 |
| Always Ready Training Limited | Education | 2019 |
| Ameva Leisure Ltd | Hospitality | 2025 |
| AMF Access Limited | Information & communication | 2019 |
| Aminopure Ltd | Wholesale & retail | 2025 |
| Amity Business Analyst Limited | Information & communication | 2015 |
| Amna Care Domiciliary Ltd | Administrative & support | 2016 |
| Amna Holdings Ltd | Financial services | 2026 |
| Amtech Rapid Prototyping Ltd | Manufacturing | 2005 |
| AMW Accounting Ltd | Professional & scientific | 2020 |
| Anakara Kebab and Pizza Ltd | Hospitality | 2026 |
| Anchor Safety Associates Limited | Professional & scientific | 2019 |
| Anderson Offshore Contractors Ltd | Professional & scientific | 2026 |
| Anderson Services Outsourced Ltd | Professional & scientific | 2022 |
| Andrew Collins Consulting Ltd | Information & communication | 2024 |
| Andrew Dick Ltd. | Professional & scientific | 1994 |
| Andrew GUY Holdings Ltd | Professional & scientific | 2026 |
| Andrew Young & Partners Limited | Real estate | 2016 |
| Andy Sparkes Construction Limited | Construction | 2019 |
| Andys Animal Adventures Ltd | Administrative & support | 2024 |
| Angel Nails ATM Ltd | Other services | 2023 |
| Angling Wizard Ltd | Wholesale & retail | 2025 |
| Animalhelp Ltd | Professional & scientific | 2024 |
| Anthony Davis Vehicle Repairs Limited | Wholesale & retail | 2023 |
| AP Services (NE) Ltd | Professional & scientific | 2021 |
| AP Wind Ltd | Manufacturing | 2025 |
| Apex Coaching & Fitness Ltd | Arts & recreation | 2022 |
| Apex Joinery Ltd. | Construction | 2015 |
| Apex Joinery Services Ltd | Construction | 2008 |
| Apex Off-Grid Limited | Wholesale & retail | 2026 |
| Apollo Bathrooms (North East) Ltd | Wholesale & retail | 2018 |
| Appealing Delight Cakes and Pasteries Limited | Hospitality | 2025 |
| Appinite Ltd. | Information & communication | 2014 |
| APT Business Private Limited | Wholesale & retail | 2023 |
| Aquamar Limited | Professional & scientific | 2024 |
| Aquanorth Diving Centre Limited | Arts & recreation | 2017 |
| AR Cooling (NE) Limited | Energy | 2019 |
| AR the Chamber Company Limited | Hospitality | 2023 |
| Arbeia Accounting & Bookkeeping Limited | Professional & scientific | 2020 |
| Arbeia Asbestos Ltd | Administrative & support | 2018 |
| Arbeia Business Services Limited | Professional & scientific | 2002 |
| Arbeia Spanish Ltd | Education | 2026 |
| Arbeia Trading Limited | Wholesale & retail | 2012 |
| Arbia Holdings Limited | Real estate | 2023 |
| Arcas Enterprises Limited | Construction | 2018 |
| Area North Medical Ltd | Transport & logistics | 2024 |
| Ares Medical Ltd | Other services | 2023 |
| Arma Renewables Ltd | Construction | 2021 |
| Arman Super Shop Ltd | Wholesale & retail | 2024 |
| Armour Electrics Ltd | Construction | 2026 |
| Armstrong Investment Property Limited | Real estate | 2020 |
| Armstrong Painting Services Ltd | Manufacturing | 2014 |
| ARP Developments N.E. Limited | Construction | 2013 |
| Arthur F&M Ltd | Construction | 2024 |
| Artifactprints Ltd | Wholesale & retail | 2026 |
| Artificial Plants and Grass Ltd | Wholesale & retail | 2024 |
| Artizey Ltd | Education | 2021 |
| Arton Court Residents Association Limited | Households | 2001 |
| Arvand River Ltd | Hospitality | 2018 |
| ARW Industrial Services Ltd | Other services | 2015 |
| AS Properties North East Ltd | Real estate | 2025 |
| Asad Bakery Ltd | Manufacturing | 2022 |
| Ascend Ecosystem Ltd | Wholesale & retail | 2025 |
| Ascend Limitless Ltd | Information & communication | 2026 |
| Ascot Care (Castleview) Limited | Health & social care | 2016 |
| Ascot Care (Coach House) Limited | Extraterritorial | 2025 |
| Ascot Care (Elizabeth House) Limited | Real estate | 2020 |
| Ascot Care (Holdings) Limited | Financial services | 2020 |
| Ascot Care (Langley House) Limited | Health & social care | 2018 |
| Ascot Care (Seaburn) Limited | Health & social care | 2021 |
| Ascot Care (ST Anne's) Ltd | Health & social care | 2012 |
| Ascot Care (Westoe Grange) Limited | Health & social care | 2012 |
| Ascot Care North East Limited | Health & social care | 2009 |
| Asgard Hi-Tech Solutions Limited | Professional & scientific | 2021 |
| Ashbrooke Court (Management) Company Limited | Real estate | 1991 |
| Ashbrooke Therapies Ltd | Health & social care | 2015 |
| Ashfield Nursery and Childcare Limited | Education | 2023 |
| Ashfield Nursery and Early Learning Centre Limited | Education | 2000 |
| Ashfield Nursery and Early Learning Centre Stanhope Road Limited | Extraterritorial | 2012 |
| Ashmark Ltd | Real estate | 2017 |
| Asnanotech Limited | Professional & scientific | 2023 |