| A.T Tiling NE Ltd | Construction | 2019 |
| A.V. Taylor Holdings Limited | Extraterritorial | 2024 |
| A1 Car Valet Services Limited | Other services | 2000 |
| A1 Chop Suey House Takeaway Limited | Hospitality | 2024 |
| A1 Decking Ltd | Construction | 2019 |
| A1 Industrial Trucks Limited | Other services | 2022 |
| A1 Infinite Performance Limited | Arts & recreation | 2018 |
| A1 Motors Ltd | Wholesale & retail | 2021 |
| A1 Property Consultants Ltd | Real estate | 2022 |
| A1 Property Solutions Ltd | Real estate | 2018 |
| A1 Window Cleaning Limited | Administrative & support | 2005 |
| A10 Mechanical Services Ltd | Professional & scientific | 2024 |
| A12FLOORING Ltd | Construction | 2026 |
| A184 Limited | Professional & scientific | 2018 |
| A2B Solutions Ltd | Extraterritorial | 2023 |
| A2ELEVATION Ltd | Information & communication | 2025 |
| A2Z Fire Protection Holdings Limited | Financial services | 2022 |
| A3 Engineering Services Ltd | Professional & scientific | 2019 |
| A3 Properties & Estates Limited | Real estate | 2024 |
| A4V Services Ltd | Professional & scientific | 2018 |
| AA & DA Ltd | Information & communication | 2021 |
| AA Construction Utilities Ltd | Construction | 2010 |
| AA Enterprises Private Ltd | Wholesale & retail | 2020 |
| AA Heating & Plumbing Limited | Professional & scientific | 2026 |
| AA Portfolio (North East) Limited | Real estate | 2025 |
| AA Properties (North East) Limited | Real estate | 2025 |
| AA Real Estate (North East) Limited | Real estate | 2026 |
| AA Shop Local Limited | Wholesale & retail | 2026 |
| AAA Drycleaners Ltd | Other services | 2021 |
| AAA Health Limited | Wholesale & retail | 2019 |
| AAA Pharm Ltd | Health & social care | 2022 |
| AAA Wholesale Ltd | Wholesale & retail | 2020 |
| AAC & Partners Ltd | Professional & scientific | 2023 |
| AAC Enterprise Ltd | Information & communication | 2022 |
| AAC Properties (Newcastle) Limited | Real estate | 2021 |
| Aadonretail Ltd | Wholesale & retail | 2026 |
| Aalto Marine Services GB Ltd | Professional & scientific | 2024 |
| AAM Accountancy Ltd | Professional & scientific | 2016 |
| Aamk Chopwell Convenience Store Ltd | Wholesale & retail | 2022 |
| Aamk Properties Ltd | Real estate | 2022 |
| AAO Capital Ltd | Construction | 2021 |
| Aapt Orthopaedics Limited | Health & social care | 2013 |
| Aapt Property Limited | Real estate | 2023 |
| Aarambh Limited | Wholesale & retail | 2025 |
| Aaravnan Retailer Ltd | Wholesale & retail | 2023 |
| Aardvark Enterprises Ltd | Hospitality | 2019 |
| Aarhus Trading Limited | Hospitality | 2022 |
| Aaron's Call Limited | Other services | 2019 |
| Aaryaan Medical Limited | Health & social care | 2019 |
| AAS Holdings Ltd | Manufacturing | 2023 |
| Aash Group (North East) Limited | Real estate | 2022 |
| Aayra Capital Limited | Real estate | 2024 |
| AAZ Takeaway Limited | Hospitality | 2026 |
| AB Beauty Aesthetics Ltd | Other services | 2026 |
| AB Health and Wellness Ltd | Other services | 2018 |
| AB Investment Group Limited | Real estate | 2021 |
| AB Psychology Ltd | Health & social care | 2024 |
| AB Training Academy Ltd | Education | 2019 |
| AB Transportation Ltd | Transport & logistics | 2026 |
| AB21 Healthcare Limited | Health & social care | 2021 |
| ABA Leisure (Five) Limited | Hospitality | 2010 |
| ABA Leisure (IP) Limited | Hospitality | 2009 |
| ABA Leisure (Two) Limited | Hospitality | 2014 |
| ABA Leisure Limited | Hospitality | 2008 |
| Abamax UK Ltd | Wholesale & retail | 2020 |
| Abba North East Limited | Construction | 2016 |
| Abbey Engineering Plumbing & Heating Services Limited | Wholesale & retail | 2009 |
| Abbey Heights Residents Management Company Limited | Households | 2020 |
| Abbey's Hebburn Village Ltd | Hospitality | 2017 |
| Abbeyfield Northumbria | Health & social care | 1961 |
| Abbiather’S Ltd | Health & social care | 2025 |
| Abbotsford Terrace Management (1997) Company Limited | Households | 1997 |
| Abby Court Developments Ltd | Construction | 2022 |
| Abca Bidco Limited | Financial services | 2021 |
| Abca Systems Group Limited | Construction | 2020 |
| Abca Systems Limited | Construction | 2007 |
| Abca Topco Limited | Financial services | 2021 |
| Abdul 143 Property Ltd | Real estate | 2020 |
| Abdullahlimited Ltd | Wholesale & retail | 2025 |
| Abel Paun Logistics Limited | Transport & logistics | 2025 |
| Abela Access Limited | Construction | 2026 |
| Abercorn Ventures Limited | Professional & scientific | 2024 |
| Abercrombies Interiors Ltd | Wholesale & retail | 2024 |
| Aberdovey Developments Limited | Construction | 2014 |
| Aberlon Limited | Administrative & support | 2019 |
| Aberturret Advisors Limited | Administrative & support | 2012 |
| Aberystwyth Student Accommodation Limited | Hospitality | 2013 |
| Abest Accounting Ltd | Professional & scientific | 2017 |
| Abest Accounts & Payroll Ltd | Professional & scientific | 2025 |
| Abfa Property Limited | Real estate | 2020 |
| ABI Madu Ltd | Real estate | 2020 |
| Abiaim Limited | Information & communication | 2025 |
| Abingdon BUS Company Limited | Professional & scientific | 1996 |
| Able Agency Limited | Professional & scientific | 2025 |
| Ablebell Investments Limited | Real estate | 2016 |
| Ablo Property Limited | Real estate | 2025 |
| ABM Energy Ltd | Construction | 2019 |
| Abmas Engineering Limited | Manufacturing | 2004 |
| Abmb Limited Liability Partnership | | 2023 |
| Abmtech Ltd | Professional & scientific | 2025 |