| Abdulhanan Ltd | Wholesale & retail | 2025 |
| Abel Ricardo Logistics Limited | Transport & logistics | 2025 |
| ABH Stars Ltd | Wholesale & retail | 2021 |
| Abhtechnical Ltd | Professional & scientific | 2022 |
| Abidco Ltd | Health & social care | 2018 |
| Abigail Roberts-Law Ltd | Information & communication | 2023 |
| Abin Raju Logistics Ltd | Transport & logistics | 2025 |
| ABJ Offshore Services Limited | Professional & scientific | 2019 |
| Able Property Investments Limited | Real estate | 2010 |
| Ablego Ventures Ltd | Transport & logistics | 2025 |
| Ablett Fabrications Ltd | Administrative & support | 2018 |
| Abode Lettings and Property Services Ltd | Households | 2024 |
| Abrar Shah Best Shop Ltd | Wholesale & retail | 2025 |
| Abrarconnect Ltd | Information & communication | 2025 |
| Abrook Consultants Limited | Professional & scientific | 2017 |
| Absolute Commercial Services (UK) Limited | Real estate | 2023 |
| Absolute Plumbing and Maintenance Limited | Households | 2018 |
| Absolute Sustainability Limited | Manufacturing | 2022 |
| Absolutely Sun & Beauty Limited | Other services | 2015 |
| Abtech International Limited | Construction | 2022 |
| ABU AL Khalil Welfare CIC | Public administration | 2024 |
| ABU Emaan Consulting Ltd | Professional & scientific | 2024 |
| Abuali Ltd | Construction | 2025 |
| Abundants Scaffolding Ltd | Construction | 2025 |
| Abuza NE Limited | Hospitality | 2024 |
| Abyan Ltd | Professional & scientific | 2026 |
| AC Finance Limited | Financial services | 2000 |
| AC Scaffolding Services Limited | Construction | 2024 |
| AC Zanfir Logistics Limited | Transport & logistics | 2026 |
| Academy Bathrooms Ltd | Construction | 2022 |
| ACB Telecoms Limited | Information & communication | 2019 |
| Access Coating Specialists Ltd | Professional & scientific | 2019 |
| Access Insulation & Coatings Ltd | Construction | 2021 |
| Access Kings Ltd | Professional & scientific | 2026 |
| Access Select Limited | Construction | 2017 |
| Access the Inaccessible Ltd | Construction | 2025 |
| Accl Education Limited | Education | 2020 |
| Accl Leisure Limited | Arts & recreation | 2025 |
| Accountancy 365 Ltd | Professional & scientific | 2022 |
| Accountax Tees Ltd | Professional & scientific | 2022 |
| Accounting Direct Ltd | Professional & scientific | 2021 |
| Ace Autos Middlesbrough Ltd | Wholesale & retail | 2018 |
| Ace Autos NE Ltd | Wholesale & retail | 2025 |
| Ace Offshore (NE) Limited | Construction | 2016 |
| Ace Rental NE Limited | Administrative & support | 2025 |
| Ace Rentals NE Limited | Transport & logistics | 2024 |
| Acefold Limited | Professional & scientific | 2017 |
| Achieve Concierge Limited | Professional & scientific | 2023 |
| Achieve Hospitality Ltd | Professional & scientific | 2019 |
| Achieve Professionals Limited | Administrative & support | 2023 |
| ACI Construction Ltd | Manufacturing | 2026 |
| Acklam Estates Ltd | Real estate | 2024 |
| Acklam Foods Limited | Hospitality | 2025 |
| Acklam Intruder Alarms Ltd | Administrative & support | 2018 |
| Acklam Maintenance Services Limited | Manufacturing | 1997 |
| Acklam New WOK Food Ltd | Hospitality | 2021 |
| Acklam Park Limited Liability Partnership | | 2008 |
| Acklam Properties Ltd | Real estate | 2025 |
| Acklam Pubs Limited | Hospitality | 2017 |
| Acklam Restaurant Ltd | Hospitality | 2026 |
| Acklam Rugby Club Limited | Arts & recreation | 1980 |
| Acklam Taxi Ltd | Transport & logistics | 2025 |
| Acobray Security Ltd | Administrative & support | 2024 |
| Acorn ICT Ltd | Information & communication | 2022 |
| Acorn Vehicle Repairs Limited | Wholesale & retail | 2026 |
| Acoustic Pixel Limited | Information & communication | 2017 |
| Acrobaticarts Circus Entertainment Ltd | Arts & recreation | 2022 |
| ACT Excel Limited | Administrative & support | 2015 |
| ACT Response Ltd | Administrative & support | 1998 |
| ACT Safeguard Limited | Administrative & support | 2015 |
| Actes Trust | Administrative & support | 2001 |
| Action Glass & Glazing Limited | Construction | 2003 |
| Active Aura Ltd | Wholesale & retail | 2023 |
| Active Tees Valley Community Interest Company | Education | 2017 |
| Active Wholesale Limited | Wholesale & retail | 2023 |
| Active World Ltd | Real estate | 2025 |
| Activewearhub Limited | Wholesale & retail | 2024 |
| Acuity AI Education Ltd | Professional & scientific | 2025 |
| Acute Build Limited | Construction | 2025 |
| Acws Property Services Limited | Real estate | 2009 |
| AD Construction Consultants Limited | Professional & scientific | 2022 |
| AD Group of Companies Limited | Manufacturing | 2025 |
| AD Network Solutions (UK) Limited | Information & communication | 2016 |
| AD Shanmukha Logistics Limited | Transport & logistics | 2025 |
| ADA Retail (Berwick Hills) Ltd | Wholesale & retail | 2021 |
| Adam Anwar Limited | Hospitality | 2022 |
| Adam Blenkinsop Rigging Ltd | Construction | 2015 |
| Adam Electrics Teesside Ltd | Construction | 2025 |
| Adam K Electrics Ltd | Construction | 2022 |
| Adam Love Holdings Ltd | Financial services | 2024 |
| Adam Properties (NE) Ltd | Real estate | 2024 |
| Adam Stockdale Limited | Transport & logistics | 2022 |
| Adamhs Ltd | Health & social care | 2024 |
| Adamo Fashion Ltd | Wholesale & retail | 2020 |
| Adamona Ltd | Wholesale & retail | 2025 |
| Adams Barber (Fishburn) Ltd | Other services | 2024 |
| Adams J Ltd | Construction | 2016 |
| Adapt Architectural Solutions Limited | Professional & scientific | 2010 |
| Adaptibles CIC | Education | 2025 |
| ADC Renewables Ltd | Construction | 2021 |