| 1ST Choice Skip Hire North East Ltd | Water & waste | 2003 |
| 2PO2 Group Ltd | Administrative & support | 2017 |
| 462 Project Management Ltd | Professional & scientific | 2025 |
| 462 Property Holdings Ltd | Real estate | 2026 |
| 4LYF Limited | Wholesale & retail | 2024 |
| 64 Golden Aroma Ltd | Hospitality | 2026 |
| 711 Digital Markting Ltd | Professional & scientific | 2025 |
| A & B Connect Ltd | Wholesale & retail | 2022 |
| A 4 Thought Ltd | Extraterritorial | 2023 |
| A B Shellfish Limited | Agriculture & fishing | 2010 |
| A M Johansson Ltd | Construction | 2026 |
| A Mcdonald Logistics Limited | Transport & logistics | 2015 |
| A P B Inspection Limited | Professional & scientific | 2020 |
| A Place to Escape Ltd | Arts & recreation | 2024 |
| A S Gillow Properties Ltd | Real estate | 2016 |
| A Time 4 YOU Psychological Services C.I.C. | Health & social care | 2010 |
| A to Z Capital Ltd | Real estate | 2023 |
| A. Brotton Engineering Limited | Manufacturing | 2017 |
| A.I.L Property Investments Ltd | Real estate | 2024 |
| A.I.L Property Specialists Ltd | Real estate | 2023 |
| A.King Lettings & Rentals Ltd | Real estate | 2013 |
| A2BLIFTING Ltd | Construction | 2021 |
| AA Security Electrical Ltd | Construction | 2022 |
| AAA Roofing Limited | Construction | 2016 |
| AAA ZT Ltd | Hospitality | 2025 |
| Aaradhi Ltd | Real estate | 2023 |
| Aase Ltd | Construction | 2025 |
| AB Redcar Ltd | Other services | 2021 |
| Abingdon Pizzeria Ltd | Hospitality | 2024 |
| Abode Property (SE) LLP | | 2021 |
| Abridge Construction Limited | Construction | 2009 |
| Absolute Antibody Limited | Manufacturing | 2012 |
| Absolute Healthcare NE Ltd | Health & social care | 2025 |
| Abundia Biomass-To-Liquids Limited | Manufacturing | 2020 |
| Acca Safety Ltd | Construction | 2020 |
| Acrepearl Limited | Households | 1984 |
| AD Instrumental Ltd | Professional & scientific | 2018 |
| AD PUB Leisure Limited | Hospitality | 2018 |
| Adapt-Able Ltd | Construction | 2021 |
| ADB Accounting Solutions Ltd | Administrative & support | 2016 |
| Addison LET Ltd | Households | 2025 |
| Adelle Gaunt Limited | Health & social care | 2003 |
| Adventure North East Ltd | Arts & recreation | 2023 |
| ADW Electrical Services Limited | Construction | 2021 |
| AEP (NE) LLP | | 2012 |
| AG Elec Solutions Ltd | Construction | 2025 |
| AGN Inspection Services Ltd | Professional & scientific | 2025 |
| AH Elliott Logistics Ltd | Transport & logistics | 2025 |
| Ahrikai Ltd | Wholesale & retail | 2024 |
| Aiding YOU Mobility Ltd | Wholesale & retail | 2021 |
| Ainsley Buchanan Limited | Arts & recreation | 2024 |
| Ainsworth Advance Ltd | Manufacturing | 2019 |
| Aion Process Engineering Ltd | Professional & scientific | 2018 |
| Aire Homes Ltd | Real estate | 2020 |
| AJH Group Construction Ltd | Construction | 2021 |
| AJM Safety Ltd | Professional & scientific | 2023 |
| AK Barbers Ltd | Other services | 2023 |
| AKA Williams Limited | Real estate | 2019 |
| Akaran Ltd | Wholesale & retail | 2018 |
| Akpropertygetaways Limited | Hospitality | 2026 |
| Al-Rahman Mosque Limited | Other services | 2025 |
| Alagray Ltd | Construction | 2025 |
| Alder UK Developments Ltd | Real estate | 2019 |
| Aldj Property Limited | Real estate | 2024 |
| ALL Wrapped UP Redcar Ltd | Hospitality | 2026 |
| Allan Watkins Shutdown Work Limited | Manufacturing | 2017 |
| Allendale Components Limited | Manufacturing | 2003 |
| Alnmouth Drive 1971 Limited | Extraterritorial | 2014 |
| Alpek Polyester UK Ltd | Manufacturing | 2009 |
| Alpha Property NE Ltd | Households | 2023 |
| Alpha Tyres Redcar Ltd | Wholesale & retail | 2022 |
| Also Coffee Co Ltd | Wholesale & retail | 2026 |
| Amav Holdings LLP | | 2021 |
| Amazing Grace - Teesside | Other services | 2011 |
| Amber Accommodation Ltd | Real estate | 2021 |
| Amco Property Limited | Construction | 2018 |
| AMH Transport Compliance Ltd | Professional & scientific | 2023 |
| AML Investments (North East) Limited | Real estate | 2016 |
| Analytical Technical Services Ltd. | Professional & scientific | 2018 |
| Anamco Management Services Limited | Professional & scientific | 2015 |
| Anchorage Homes & Premises Ltd | Other services | 2018 |
| Andrew Crawford Property Services Ltd | Construction | 2014 |
| Andrew Dowson Limited | Professional & scientific | 2013 |
| Angel Nails Redcar Ltd | Other services | 2026 |
| Angelo's Pizzeria 4U Ltd | Hospitality | 2021 |
| AP Sports Turf Maintenance Ltd | Administrative & support | 2018 |
| Aphorism Healthcare Ltd | Health & social care | 2025 |
| Apollo Holdco 2025 Limited | Financial services | 2022 |
| Apples Learning Solutions Ltd | Wholesale & retail | 2015 |
| Applestop Limited | | 1980 |
| Approach-Development (NE) Ltd. | Other services | 2014 |
| APR Project Services Ltd | Professional & scientific | 2023 |
| Aptrek Limited | Wholesale & retail | 2025 |
| Arakna Logistics Ltd | Transport & logistics | 2025 |
| ARC Aerial Imaging Limited | Professional & scientific | 2015 |
| Arcenstone CIC | Education | 2024 |
| Arcmech Ltd | Professional & scientific | 2025 |
| Ardan Lettings & Property Management Limited | Real estate | 2013 |
| Armada Guesthouse (Redcar) Limited | Hospitality | 2005 |
| Arthur Aesthetics Ltd. | Other services | 2022 |