| AL Gelsin Ltd | Construction | 2021 |
| AL Noor Fashions Ltd | Wholesale & retail | 2024 |
| AL Noor Kitchen Ltd | Manufacturing | 2026 |
| AL Northampton Car Sales Ltd | Wholesale & retail | 2024 |
| AL Rehman Books Ltd | Wholesale & retail | 2025 |
| AL Reys Ltd | Hospitality | 2025 |
| Al-Abubakkar Motors Limited | Wholesale & retail | 2019 |
| Al-Ajal Ltd | Wholesale & retail | 2026 |
| Al-Amin Brothers Ltd | Hospitality | 2014 |
| Al-Haqq UK Ltd | Hospitality | 2017 |
| Al-Khashab Limited | Real estate | 2008 |
| ALA Construction Limited | Construction | 2016 |
| Alaa Eats Ltd | Hospitality | 2024 |
| Aladen Limited | Information & communication | 2026 |
| Alam Cargo and Travel Ltd | Transport & logistics | 2018 |
| Alam Mini Market Ltd. | Wholesale & retail | 2019 |
| Alam Supermarket Ltd | Wholesale & retail | 2022 |
| Alamin Motors Limited | Wholesale & retail | 2025 |
| Alan Brown Consultancy Limited | Information & communication | 2012 |
| Alan Godrich (Sewing Machines) Limited | Manufacturing | 1972 |
| Alan Weddell Drylining & Plastering Limited | Construction | 2009 |
| Alarix Transport Ltd | Transport & logistics | 2026 |
| Alaseo Limited | Information & communication | 2015 |
| Alaynna Retail Limited | Wholesale & retail | 2025 |
| Alba Insulation Limited | Construction | 2008 |
| Alban Crafts Ltd | Construction | 2012 |
| Albans Catering Limited | Administrative & support | 2016 |
| Albany Carpet Contracts (Holdings) Ltd | Wholesale & retail | 2021 |
| Albany Carpet Contracts Limited | Wholesale & retail | 1995 |
| Albany Court (Cliftonville) Management Company Limited | Households | 2000 |
| Albany Investments (Aylesbury) Ltd | Real estate | 2022 |
| Albermarle Contracts Ltd | Construction | 2013 |
| Albert Road Properties Northants Limited | Real estate | 2024 |
| Albert Watts Hairdressers Limited | Other services | 2008 |
| Alberti Group Ltd | Professional & scientific | 2022 |
| Albina Group Ltd | Construction | 2026 |
| Albion (Northampton) Cars Ltd | Transport & logistics | 2025 |
| Albion Court (Northampton) RTM Company Limited | Households | 2025 |
| Albion House Properties Limited | | 1987 |
| Albion Knights (Properties) Limited | Real estate | 2018 |
| Albion Mews Management Company Ltd | Real estate | 2006 |
| Albion Northampton Limited | Construction | 2021 |
| Albion Property Group LLP | | 2017 |
| Albury Investments Limited | Real estate | 2017 |
| Alchemy Consultancy Partnership Limited | Professional & scientific | 2016 |
| Alchemy Recruitment Ltd | Administrative & support | 2021 |
| Alchemy VA Ltd | Administrative & support | 2019 |
| Alcona Limited | Transport & logistics | 2013 |
| Alconbury Apartments Residents Management Company Limited | Households | 2026 |
| Alconstruction Brickwork Ltd | Construction | 2026 |
| Alcyon Consulting Ltd | Information & communication | 2014 |
| Alderman Roofing Limited | Construction | 2003 |
| Alderson & Co Services Ltd | Construction | 2025 |
| Aldonida Limited | Real estate | 2023 |
| Aldotiler Limited | Other services | 2017 |
| Aldra Install Ltd | Construction | 2022 |
| Aldridge Taxation and Accountancy Services Limited | Professional & scientific | 2003 |
| Alds London Ltd | Construction | 2019 |
| Aldufin Limited | Real estate | 2021 |
| Ale&Miha Ltd | Transport & logistics | 2013 |
| ALE13XIA&CO Ltd | Transport & logistics | 2024 |
| Alebia Limited | Transport & logistics | 2024 |
| Aleem Satti Ltd | Transport & logistics | 2025 |
| Alegricom Ltd | Construction | 2018 |
| Alejandra Cleaning Services Ltd | Administrative & support | 2025 |
| Aleksanders Borodins Ltd | Extraterritorial | 2023 |
| Alemar Express Ltd | Transport & logistics | 2025 |
| Aleon Services (UK) Limited | Health & social care | 2014 |
| Alera Properties Ltd | Real estate | 2023 |
| Alerting Hub Ltd | Information & communication | 2020 |
| Alesi Studios (Northampton) Ltd | Other services | 2025 |
| Alesi Studios Ltd | Other services | 2024 |
| Alessandro Consultants Ltd | Professional & scientific | 2026 |
| Alessia Prime Transport Ltd | Transport & logistics | 2023 |
| Alex 2011 Ltd | Real estate | 2026 |
| Alex Ayres Associates Limited | Administrative & support | 2017 |
| Alex C. Electrical Ltd | Construction | 2023 |
| Alex ION 21 Ltd | Transport & logistics | 2025 |
| Alex Kuhne & Company Ltd | Professional & scientific | 2025 |
| Alex LE Guevel Sports Consultancy Limited | Professional & scientific | 2023 |
| Alex Lynn Racing Limited | Arts & recreation | 2010 |
| Alex Prime Limited | Transport & logistics | 2026 |
| Alexa Interior Solution Ltd | Construction | 2026 |
| Alexander Cleaning & Maintenance Limited | Administrative & support | 2015 |
| Alexander Oliver Ltd | Real estate | 2023 |
| Alexander Project Consulting Limited | Professional & scientific | 2022 |
| Alexandra Terrace Real Estate Limited | Construction | 2022 |
| Alexandru M Ltd | Transport & logistics | 2016 |
| Alexandru Schiopu Transport Limited | Transport & logistics | 2019 |
| Alexandru Stefan Services Limited | Construction | 2016 |
| Alexanton Ltd | Transport & logistics | 2018 |
| Alexcontrators Ltd | Construction | 2024 |
| ALEXCRA35 Ltd | Transport & logistics | 2025 |
| Alexgrig Trans Ltd | Transport & logistics | 2015 |
| Alextoy Ltd | Construction | 2024 |
| Alfa Mortgages Limited | Financial services | 2023 |
| Alfabrick Limited | Construction | 2018 |
| Alfann Limited | Health & social care | 2020 |
| Alfco Group Ltd | Transport & logistics | 2019 |
| Alfia Languages Limited | Education | 2002 |