| Afroluxe Lounge & Restaurant Ltd | Wholesale & retail | 2025 |
| Afrosoul Kitchen Ltd | Hospitality | 2024 |
| Aftab Investments Ltd | Real estate | 2023 |
| Aftab Traders Northampton Ltd | Wholesale & retail | 2025 |
| After Rain Ltd | Manufacturing | 2024 |
| Afternoon Teas Northampton LLP | | 2021 |
| Afyrecruitment Ltd | Administrative & support | 2025 |
| AG & RJ Holdings Limited | Real estate | 2021 |
| AG Future Innovations Limited | Manufacturing | 2025 |
| AG Planning Services LLP | | 2024 |
| AG1 UK Enterprise Ltd | Health & social care | 2012 |
| AGA Development Ltd | Construction | 2023 |
| AGA Mobility Systems Limited | Health & social care | 2003 |
| Against the Tide Ltd | Other services | 2022 |
| Agastya Investments Ltd | Real estate | 2021 |
| AGB Installations Limited | Information & communication | 2017 |
| AGB Transport Limited | Transport & logistics | 2021 |
| AGC Glass UK Ltd | Manufacturing | 1990 |
| AGE Angels Ltd | Health & social care | 2014 |
| AGE UK Lindsey | Information & communication | 2000 |
| AGE UK Northamptonshire | Health & social care | 1996 |
| AGE UK Northamptonshire Trading Limited | Wholesale & retail | 1994 |
| AGE UK Northamptonshire Trust Corporation Limited | Health & social care | 2023 |
| Ageless Ltd | Health & social care | 2026 |
| Agenda Lounge Consulting Ltd | Professional & scientific | 2025 |
| Agent and Homes Limited | Real estate | 2018 |
| Ageo Transport Limited | Transport & logistics | 2012 |
| Aggregex Technology Ltd | Information & communication | 2026 |
| Aghar Ltd | Wholesale & retail | 2026 |
| Agile Conditioning Ltd | Other services | 2019 |
| Agile Practitioners Ltd | Information & communication | 2013 |
| AGILE360 Limited | Professional & scientific | 2024 |
| AGL Aruxandei Ltd | Construction | 2025 |
| AGL Construction Management Limited | Construction | 2013 |
| Agnes Cake Boxing Ltd | Manufacturing | 2025 |
| Agnieszka Talor Limited | Wholesale & retail | 2024 |
| AGO Services Ltd | Transport & logistics | 2017 |
| AGO Ventures Limited | Wholesale & retail | 2012 |
| Agora Greek Market Limited | Wholesale & retail | 2020 |
| Agprpm Ltd | Administrative & support | 2016 |
| AGR Property Ltd | Real estate | 2021 |
| Agrevise Limited | Agriculture & fishing | 1998 |
| Agri Automotive Limited | Professional & scientific | 2025 |
| Agri Indevelop Ltd | Agriculture & fishing | 2022 |
| Agri Renewable Fuels Unlimited | Water & waste | 2010 |
| Agrilec Limited | Construction | 2013 |
| AGS Sports UK Ltd | Manufacturing | 2025 |
| AGT Grimsby Limited | Transport & logistics | 2016 |
| Agtx Ltd | Professional & scientific | 2025 |
| AGW OIL & GAS Ltd | Mining & quarrying | 2017 |
| AH Braintree Limited | Financial services | 2021 |
| AH Littleover Holdco Limited | Financial services | 2020 |
| Ahad Nawaz Ltd | Wholesale & retail | 2025 |
| Ahad Studios Ltd | Professional & scientific | 2025 |
| Ahai IT Solutions Ltd | Information & communication | 2024 |
| Ahenfie Restaurant Ltd | Hospitality | 2026 |
| Ahero Ltd | Health & social care | 2018 |
| Ahiamadi Touch Limited | Health & social care | 2010 |
| Ahimsa Vegetarian Restaurant Limited | Hospitality | 2019 |
| AHM Properties Limited | Real estate | 2012 |
| Ahmed 1977 Holdings Ltd | Real estate | 2024 |
| Ahmed Construction (Northampton) Limited | Construction | 2018 |
| Ahosiesie Ltd | Manufacturing | 2026 |
| AHP Lettings Limited | Real estate | 2018 |
| AI 1 Logistics Limited | Transport & logistics | 2025 |
| AI Bear Limited | Hospitality | 2023 |
| AI Build Develop Ltd | Construction | 2025 |
| AI Hand Car Wash Ltd | Other services | 2017 |
| AI Health and Safety Ltd | Public administration | 2025 |
| AI Mobile Valeting Ltd | Other services | 2018 |
| AI Solution Engineering Ltd | Information & communication | 2026 |
| AID Reliance Ltd | Professional & scientific | 2022 |
| Aidan Coleman Limited | Arts & recreation | 2009 |
| Aidecare Ltd | Health & social care | 2012 |
| Aiden Homes Ltd | Real estate | 2022 |
| Aidios Bridgeway Limited | Professional & scientific | 2022 |
| AIE Groupuk Ltd | Construction | 2022 |
| Aiga Homes Limited | Real estate | 2016 |
| AIM Brickwork Ltd | Construction | 2024 |
| AIM Investigations Ltd | Professional & scientific | 2015 |
| Aimax Catering Services Limited | Hospitality | 2025 |
| Aimcon Surveys Ltd | Professional & scientific | 2013 |
| Aimm Driving School Ltd | Education | 2024 |
| Aimrok Holdings Ltd | Construction | 2016 |
| Ainara Ltd | Administrative & support | 2015 |
| Ainars Transport Ltd | Transport & logistics | 2022 |
| Air Artistry UK Ltd | Administrative & support | 2025 |
| Air Controlled Engineering Services Limited | Construction | 1995 |
| Air Knife Systems Limited | Manufacturing | 2019 |
| Air Pressure Test UK Ltd | Construction | 2008 |
| Air Road Transport Ltd | Transport & logistics | 2024 |
| Air Rush Ltd | Construction | 2019 |
| Air TEC Holdings Ltd | Manufacturing | 2009 |
| Air Vent Tech Ltd | Manufacturing | 2023 |
| Airecovery Ltd | Transport & logistics | 2025 |
| Airflo Ltd | Construction | 2007 |
| Airflow Streamlines Limited | Manufacturing | 2013 |
| Airinei Danut Limited | Transport & logistics | 2014 |
| Airlit Ltd | Wholesale & retail | 2025 |
| Airosephotography Limited | Professional & scientific | 2022 |