| AIM Drinks Ltd | Hospitality | 2023 |
| AIM High (Build) Ltd | Construction | 2015 |
| AIM2ACHIEVE Ltd | Education | 2024 |
| AIM4GOALS Limited | Information & communication | 2024 |
| Aimcam Limited | Manufacturing | 2013 |
| Aine Rose Daly Limited | Arts & recreation | 2021 |
| Ainsworth Insulation Limited | Extraterritorial | 1999 |
| Ainsworth Insulation Supplies Limited | Extraterritorial | 2003 |
| Aiou Ltd | Construction | 2024 |
| Air Accessories (Sheffield) Limited | Wholesale & retail | 1974 |
| Air and Housing Ltd | Construction | 2025 |
| Air Building Services Ltd | Construction | 2026 |
| Air Cat Limited | Wholesale & retail | 1991 |
| Air Centric Facilities Limited | Construction | 2018 |
| Air Centric Ventilation Limited | Construction | 2021 |
| Air Compression Technology Limited | Professional & scientific | 2003 |
| Air Global Ltd | Wholesale & retail | 2011 |
| Air Movement Technology Ltd | Construction | 2023 |
| Air Power Products Group Limited | Financial services | 2026 |
| Air Raid Clothing Ltd | Wholesale & retail | 2009 |
| Air Sheffield Ltd | Professional & scientific | 2014 |
| Air Source Heating and Servicing Ltd | Construction | 2023 |
| Air Taxis Ltd | Transport & logistics | 2014 |
| Aira Lettings Ltd | Real estate | 2023 |
| Airam Demha Y Limited | Other services | 2025 |
| Airco Engineering Limited | Information & communication | 1996 |
| Aircon Mechanical Limited | Manufacturing | 2021 |
| Aircraft Inspection and Certification Ltd | Professional & scientific | 2013 |
| Airdrop Bikes Limited | Wholesale & retail | 2014 |
| Aire & Sheaf Holdings Ltd | Households | 2024 |
| Aire Beauty Ltd | Other services | 2023 |
| Aire Venture Group Ltd | Professional & scientific | 2026 |
| Aireshelta UK Limited | Construction | 2024 |
| Airflow Cooling EOT Limited | Financial services | 2024 |
| Airflow Cooling Ltd | Construction | 2011 |
| Airflow Engineering Limited | Manufacturing | 1983 |
| Airflow Group Holdings Limited | Financial services | 2021 |
| Airflow Products Limited | Manufacturing | 2001 |
| Airfly Travels Ltd | Professional & scientific | 2025 |
| Airload Waste Management Ltd | Water & waste | 2017 |
| Airmaster Airconditioning Limited | Manufacturing | 1992 |
| Airmaster Trustees Limited | Extraterritorial | 2021 |
| Airport Business Park (Quad) Management Limited | Real estate | 2022 |
| Airport Business Park Southend Management Limited | Real estate | 2018 |
| Airprotekt Limited | Water & waste | 1994 |
| Airway Limited | Energy | 2004 |
| AIS Estates Ltd | Construction | 2024 |
| AIS Insulation Supplies Limited | Extraterritorial | 2004 |
| Aisthorpe 1967 Limited | Extraterritorial | 2014 |
| Aitch & Co Limited | Professional & scientific | 2011 |
| Aivaf Limited | Manufacturing | 1988 |
| Aiyan Delivery Ltd | Transport & logistics | 2019 |
| Aizlewood & Casson Flooring Limited | Extraterritorial | 2017 |
| Aizlewoods Flooring Specialists Limited | Construction | 1979 |
| AJ Autopro Ltd | Wholesale & retail | 2026 |
| AJ Culinary Limited | Hospitality | 2024 |
| AJ Diner Ltd | Hospitality | 2023 |
| AJ Drywall Systems Limited | Construction | 2017 |
| AJ Garden Service's Limited | Administrative & support | 2020 |
| AJ Grange Co Ltd | Hospitality | 2011 |
| AJ Hurdley Ltd | Wholesale & retail | 2026 |
| AJ Innovations Limited | Wholesale & retail | 2018 |
| AJ Interiors Ltd | Construction | 2026 |
| AJ Motoring School Limited | Education | 2025 |
| AJ Retail Ltd | Wholesale & retail | 2023 |
| AJ Tucker Ltd | Information & communication | 2016 |
| Aj's Security Ltd | Administrative & support | 2024 |
| Aj.Globalsupplies Ltd | Wholesale & retail | 2025 |
| Aj.Sial Ltd | Wholesale & retail | 2024 |
| AJA Harrison Consulting Limited | Information & communication | 2010 |
| Ajac Supplies (UK) Limited | Wholesale & retail | 2020 |
| Ajani Healthcare Limited | Health & social care | 2023 |
| Ajanta’S Vegetarian Ltd | Hospitality | 2019 |
| Ajas Services Limited | Manufacturing | 2018 |
| Ajatma Property Limited | Health & social care | 2022 |
| Ajayes Ltd | Hospitality | 2025 |
| AJC Parcels Ltd | Transport & logistics | 2014 |
| Ajc&Smc Marketing Limited | Other services | 2025 |
| Ajcollective Ltd | Arts & recreation | 2017 |
| AJE Group SY Limited | Construction | 2025 |
| AJE Plumbing and Heating Limited | Construction | 2023 |
| AJF Cladding Installations Ltd | Construction | 2021 |
| AJF Sales Ltd | Wholesale & retail | 2025 |
| Ajfs Group Limited | Financial services | 2026 |
| AJG Enterprise Ltd. | Real estate | 2013 |
| AJH Serene Limited | Health & social care | 2026 |
| Ajikape Limited | Health & social care | 2022 |
| Ajims Medical Associates Ltd | Health & social care | 2024 |
| Ajjs Hetherington Ltd | Real estate | 2022 |
| AJK Haulage Ltd | Transport & logistics | 2026 |
| Ajkop Wholesale Limited | Wholesale & retail | 2018 |
| AJM Housing Solutions Ltd | Construction | 2020 |
| AJM Property Letting Limited | Real estate | 2016 |
| AJM Property Services Ltd | Real estate | 2018 |
| Ajmc Entertainment Ltd | Hospitality | 2018 |
| Ajmi Medical Services Limited | Administrative & support | 2017 |
| Ajoors Prop Co Ltd | Real estate | 2021 |
| AJP Roofing Solutions Limited | Construction | 2014 |
| Ajpz Ltd | Administrative & support | 2017 |
| Ajrroofing Ltd | Construction | 2023 |