| AJ Mechanical Services (NE) Limited | Professional & scientific | 2022 |
| AJ Skip Hire Ltd | Water & waste | 2023 |
| AJD Consultancy Solutions Ltd | Professional & scientific | 2025 |
| AJD Marketing Ltd | Information & communication | 2026 |
| Ajet Properties Ltd | Real estate | 2020 |
| AJH Pipefitting Solutions Ltd | Mining & quarrying | 2017 |
| AJM Technical Services Ltd | Professional & scientific | 2023 |
| Ajmhughes Ltd | Transport & logistics | 2026 |
| Ajmm Ltd | Hospitality | 2025 |
| AJP Confined Space Ltd | Administrative & support | 2025 |
| AJS Brands Ltd | Financial services | 2023 |
| AJS Motorsport Marketing Limited | Professional & scientific | 2025 |
| AJS Rigging Solutions Limited | Professional & scientific | 2019 |
| AJS Takeaway Ltd | Hospitality | 2026 |
| Ajsjp Ltd | Wholesale & retail | 2026 |
| Ajtinst Ltd | Professional & scientific | 2024 |
| AK Construction and Management Ltd | Construction | 2019 |
| AK Diagnostics Limited | Health & social care | 2016 |
| AK Rentals NE Limited | Administrative & support | 2024 |
| Akbar Restaurant (Middlesbrough) Limited | Hospitality | 2008 |
| Akep Eandi Solutions Ltd | Professional & scientific | 2015 |
| Akhtar & Akhtar Properties Limited | Real estate | 2025 |
| Akhter Investment Group Ltd | Wholesale & retail | 2025 |
| Akileh’S Ltd | Real estate | 2025 |
| Akinbiyimarkb Limited | Wholesale & retail | 2025 |
| AKR Motor Sales Ltd | Wholesale & retail | 2024 |
| Akr.Z Homes Limited | Real estate | 2024 |
| AKS Collection Limited | Wholesale & retail | 2025 |
| AKS Engineering Services Limited | Professional & scientific | 2007 |
| Akshat Group Limited | Wholesale & retail | 2025 |
| Akstephenson Contractors Ltd | Manufacturing | 2026 |
| Akurei MMA Academy Ltd | Health & social care | 2019 |
| AL Araak Teesside Ltd | Wholesale & retail | 2025 |
| AL G Networks Limited | Construction | 2016 |
| AL Mukhtar Ltd | Manufacturing | 2025 |
| AL Technical Consultancy Services Ltd | Professional & scientific | 2024 |
| AL Wael Ltd | Hospitality | 2025 |
| AL Wasi Textiles Limited | Wholesale & retail | 2025 |
| Al-Falahi and Sons Ltd | Administrative & support | 2025 |
| Al-Fursan United Industrial Ltd | Administrative & support | 2024 |
| Al-Mishkat Global for Development Limited | Health & social care | 2026 |
| Al-Qawiyy Ltd | Wholesale & retail | 2025 |
| Alan & Lynn Ltd | Wholesale & retail | 2011 |
| Alan Dobson Fire Equipment Sales Ltd | Manufacturing | 2025 |
| Alan Ransome Sporting Goods Group Limited | Wholesale & retail | 1974 |
| Alanya 15 Ltd | Other services | 2024 |
| Albie Developments Ltd | Construction | 2020 |
| Albridge Drylining Ltd | Construction | 2019 |
| Alcalcars Ltd | Transport & logistics | 2026 |
| Alchemy Consulting NE Ltd | Professional & scientific | 2023 |
| Alcotron Entertainments Limited | Wholesale & retail | 2015 |
| Alder & Partners Ltd | Professional & scientific | 2025 |
| Alder and Bowcock Limited | Real estate | 2020 |
| Alea Events Limited | Administrative & support | 2014 |
| Alex Bone Music Limited | Extraterritorial | 2023 |
| Alex P Jones Limited | Health & social care | 2016 |
| Alex Shelton Limited | Manufacturing | 2026 |
| Alexander Albert Limited | Professional & scientific | 2022 |
| Alexander Bejewels Costumes Ltd | Wholesale & retail | 2026 |
| Alexander James Electrical Services Ltd | Construction | 2025 |
| Alexandra Jayne Ltd | Real estate | 2020 |
| Alexandra Nicole Limited | Other services | 2016 |
| Alexpvl Ltd | Transport & logistics | 2025 |
| Alfar Traders Ltd | Wholesale & retail | 2021 |
| Alfurqan Developers Ltd | Professional & scientific | 2019 |
| Algrow Ltd | Wholesale & retail | 2025 |
| ALH (Middlesbrough) Limited | Administrative & support | 2016 |
| ALI Decorater and Designer Limited | Other services | 2022 |
| ALI Hassan Carwash Limited | Administrative & support | 2025 |
| Ali's House Removal Limited | Transport & logistics | 2022 |
| Ali's Superstore (North East) Limited | Wholesale & retail | 2020 |
| Alif Gadget Ltd | Wholesale & retail | 2024 |
| Align & Define Ltd | Education | 2024 |
| Alin G.F Ltd | Construction | 2025 |
| Alina Decoration & Designers Ltd | Professional & scientific | 2020 |
| Alison Laws Horsemanship Ltd | Agriculture & fishing | 2023 |
| Alison Moullaali Limited | Financial services | 2016 |
| Alison Poole Designs Limited | Professional & scientific | 2014 |
| Alistair Jopling Builders Ltd | Construction | 2020 |
| Aliyah Creations Limited | Other services | 2024 |
| Aljumah and Ashiti Limited | Real estate | 2021 |
| Alkatso Ltd | Real estate | 2022 |
| ALL Dolled UP Bridal Ltd | Administrative & support | 2019 |
| ALL Dolled UP HQ Limited | Other services | 2022 |
| ALL One Living Ltd | Administrative & support | 2020 |
| ALL Round Protection Limited | Administrative & support | 2024 |
| ALL Things Sourcing UK Ltd | Administrative & support | 2024 |
| ALL TOM Structures Limited | Construction | 2025 |
| Allaboutthesuit Ltd | Wholesale & retail | 2019 |
| Allan Grange Management Ltd | Real estate | 2021 |
| Allan Offshore Limited | Professional & scientific | 2025 |
| Allcon Controls Ltd | Information & communication | 2024 |
| Alleina Ltd | Wholesale & retail | 2024 |
| Allfoods Wholesale Co. Ltd | Wholesale & retail | 2025 |
| Alllift Ltd | Professional & scientific | 2022 |
| Alma Visa Consultants Ltd | Professional & scientific | 2026 |
| Almiaari Ltd | Real estate | 2020 |
| Almonds Cleans Limited | Administrative & support | 2025 |
| Alobaidy Transporter Limited | Transport & logistics | 2023 |
| Alora Travel & Tours Ltd | Administrative & support | 2024 |