| AK Properties (Wearside) Ltd | Real estate | 2025 |
| AK Scaffolding & Containment Services Ltd | Construction | 2020 |
| Ak&B Catering Limited | Hospitality | 2017 |
| Akkistrading Ltd | Financial services | 2024 |
| AKM Bespoke Ltd | Construction | 2026 |
| AKO Services Limited | Other services | 2008 |
| Akrivia Ltd | Professional & scientific | 2017 |
| AKS Food and Wine Limited | Wholesale & retail | 2021 |
| Akshayan Retail Ltd | Wholesale & retail | 2025 |
| AL EZZ for Import and Export Ltd | Wholesale & retail | 2024 |
| Al-Falaq Counselling Community Interest Company | Health & social care | 2025 |
| Al-Huda Global Limited | Wholesale & retail | 2025 |
| Alan M Hill Limited | Professional & scientific | 2012 |
| Alan Pickin Associates Ltd | Financial services | 2013 |
| Alan Potter Surveying Limited | Professional & scientific | 2009 |
| Alan's Ropes & Blades Ltd | Manufacturing | 2023 |
| Alatopipero Limited | Professional & scientific | 2026 |
| Albatross BUS and Coach Limited | Transport & logistics | 2017 |
| Albisa Ltd | Real estate | 2026 |
| Albos Associates Ltd | Professional & scientific | 2014 |
| Albos Properties Ltd | Real estate | 2019 |
| Albow LLP | | 2018 |
| Alchemist Consultants Limited | Professional & scientific | 2017 |
| Alder Grayson Holdings Limited | Administrative & support | 2022 |
| Alderly Properties Ltd | Real estate | 2023 |
| Alderson Cleaning Services Ltd | Water & waste | 2005 |
| Alderson Services (Holdings) Limited | Professional & scientific | 2013 |
| Alechenu E-Comm Ltd | Wholesale & retail | 2023 |
| Alex 55 Ltd | Other services | 2023 |
| Alex Grange Developments Limited | Construction | 2025 |
| Alexan Enterprises Ltd | Wholesale & retail | 2025 |
| Alexander Homes (NE) Ltd | Real estate | 2025 |
| Alexander Housing Group Ltd | Real estate | 2024 |
| Alexander Jackson Limited | Professional & scientific | 2022 |
| Alexander Roland Giles Limited | Information & communication | 2015 |
| Alexanders House Ltd. | Health & social care | 2017 |
| Alexandra Estates Ltd | Real estate | 2024 |
| Alexandra Housing NE Limited | Real estate | 2025 |
| Alexandra Mews (Sunderland) Management Limited | Households | 1988 |
| Alexandra Mews Management Limited | Real estate | 2019 |
| ALH IT Services Ltd | Information & communication | 2016 |
| ALI Geez NE Ltd | Hospitality | 2018 |
| ALI Kaya Properties Ltd | Real estate | 2024 |
| ALI Pizza Ltd | Hospitality | 2025 |
| Alika Ltd | Real estate | 2024 |
| Alina MAY Consultancy Ltd | Professional & scientific | 2018 |
| Aline Propertys Ltd | Real estate | 2026 |
| Aline Residentials Ltd | Real estate | 2026 |
| Alinhealth Ltd | Health & social care | 2021 |
| Alitepropertymaintenance Limited | Construction | 2026 |
| Alizas Group Ltd | Hospitality | 2025 |
| ALK Offshore Ltd | Construction | 2026 |
| ALL About Games Consulting Limited | Other services | 2021 |
| ALL About YOU North East Community Interest Company | Arts & recreation | 2016 |
| ALL in Renewable Resources Ltd | Energy | 2019 |
| ALL Sorts of Health CIC | Education | 2025 |
| ALL Things Decontamination (ATD) Ltd | Administrative & support | 2023 |
| ALL1N Property Ltd | Real estate | 2021 |
| Allbro Enclosures Ltd | Financial services | 2021 |
| Alldec (Northern) Limited | Construction | 2001 |
| Alldec Holdings Limited | Financial services | 2023 |
| Allen Champion & Shaw Limited | Professional & scientific | 2022 |
| Allen Tomas & Co Financial Management Ltd. | Financial services | 2014 |
| Alliance Plumbing & Heating N.E Ltd | Extraterritorial | 2021 |
| Alliance Tools Limited | Administrative & support | 2015 |
| Allsopp Leisure Ltd | Hospitality | 2025 |
| Alltrade Property Solutions Ltd | Administrative & support | 2026 |
| ALM Property Development and Investment Ltd | Real estate | 2025 |
| Almae Automation and Renewable Energy Limited | Construction | 2023 |
| Almighty JIU Jitsu CIC | Arts & recreation | 2026 |
| Alnwick Golf Breaks Limited | Arts & recreation | 2021 |
| Aloft Business World UK Ltd | Administrative & support | 2025 |
| Alotbsol Ltd | Information & communication | 2026 |
| Alpagro Estates Limited | Administrative & support | 2021 |
| Alpha Control Solutions Ltd | Construction | 2018 |
| Alpha Media Productions Ltd | Information & communication | 2023 |
| Alpha Scrummy Limited | Other services | 2022 |
| Alpha Traders (NE) Ltd | Hospitality | 2025 |
| ALPHA7 Express Ltd | Transport & logistics | 2018 |
| Alphr Limited | Administrative & support | 2023 |
| Alpine Housing Ltd | Real estate | 2022 |
| Alsidra Group Ltd | Health & social care | 2024 |
| Alston Electrical Services Ltd | Manufacturing | 2015 |
| Alter EGO Healthcare Ltd | Wholesale & retail | 2024 |
| Altikulac Sunderland Ltd | Hospitality | 2020 |
| Altruism Limited | Education | 2001 |
| ALW Creative Ltd | Professional & scientific | 2023 |
| Alya Sandwich Ltd | Hospitality | 2025 |
| Alyazan Car Wash Ltd | Other services | 2023 |
| AM Brothers Limited | Wholesale & retail | 2025 |
| AM Holdings Group Ltd | Wholesale & retail | 2024 |
| AM Project Management & Consultancy Ltd | Construction | 2024 |
| AM Residents RTM Company Limited | Households | 2015 |
| AM1A TEC Limited | Information & communication | 2026 |
| Amar Chip & Fish Ltd | Hospitality | 2025 |
| Amare Roma C.I.C. | Education | 2025 |
| Amas Properties Ltd | Construction | 2013 |
| Amava Holding Ltd | Financial services | 2025 |
| Amax Assist Limited | Transport & logistics | 2024 |
| Amazing Paving Limited | Administrative & support | 2020 |