| Aikins Healthcare Ltd | Health & social care | 2017 |
| Aikiu Store Ltd | Wholesale & retail | 2024 |
| Aileron Design Ltd | Professional & scientific | 2015 |
| AIM Associates Ltd | Information & communication | 2025 |
| AIM Aurora Limited | Financial services | 2019 |
| AIM Builders and Developers Ltd | Real estate | 2025 |
| AIM Consultancy Bristol Ltd | Real estate | 2025 |
| AIM Engineers Ltd | Construction | 2023 |
| AIM Financials Ltd | Professional & scientific | 2021 |
| AIM Green Energy Ltd | Professional & scientific | 2026 |
| AIM Industries Ltd | Manufacturing | 2025 |
| AIM Investment Holdings Limited | Financial services | 2025 |
| AIM Ireland Limited | Financial services | 2022 |
| AIM Mortgages Ltd | Financial services | 2023 |
| AIM Project Management Ltd. | Professional & scientific | 2007 |
| Aimcover Limited | Households | 1986 |
| Aimee Laoise Photography Ltd | Professional & scientific | 2024 |
| Aimeetim Ltd | Real estate | 2024 |
| Aimlight Builders Limited | Construction | 2002 |
| Ainetdin Properties Holding Ltd | Real estate | 2025 |
| Ainslee Ltd | Wholesale & retail | 2020 |
| Aiolos Renewables Limited | Professional & scientific | 2026 |
| Aiom Foods Limited | Hospitality | 2022 |
| Aipairs Ltd | Wholesale & retail | 2025 |
| Aipomage Green Ltd | Information & communication | 2025 |
| Air & Solar SW Ltd | Construction | 2022 |
| Air B & C Limited | Hospitality | 2023 |
| Air Compressor Distribution Limited | Manufacturing | 2011 |
| Air CON Air Source Refrigeration Ltd | Other services | 2018 |
| Air Conditioning Bristol Ltd | Energy | 2013 |
| Air Efficient Ltd | Construction | 2023 |
| Air Giants Limited | Professional & scientific | 2020 |
| Air Hire Ltd | Extraterritorial | 2010 |
| Air Investments Ltd | Real estate | 2020 |
| Air Management Bristol Ltd | Hospitality | 2018 |
| Air Oprea SRV Limited | Manufacturing | 2025 |
| Air Quality Consultants Limited | Professional & scientific | 1993 |
| Air Systems (SW) Limited | Construction | 2001 |
| Air Xtreme Holdings Limited | Professional & scientific | 2021 |
| Air Xtreme Limited | Construction | 2008 |
| Airborne Exploration Services Ltd | Professional & scientific | 2018 |
| Airborne Views Ltd | Other services | 2017 |
| Airbus Operations Limited | Manufacturing | 1997 |
| Airbus Sparrow Limited | Extraterritorial | 2025 |
| Aircare Medical Limited | Manufacturing | 2013 |
| Aircraft Charter Ltd. | Transport & logistics | 2006 |
| Aircraft Maintenance Solutions Ltd | Manufacturing | 2009 |
| Aircraft Plywood and Timber LLP | | 2015 |
| Aire Point Consulting Ltd | Professional & scientific | 2021 |
| Airguntv Ltd | Extraterritorial | 2012 |
| Airhomesolutions Ltd | Construction | 2025 |
| Airhop Bristol Limited | Arts & recreation | 2015 |
| Airhop Guildford Limited | Arts & recreation | 2016 |
| Airhop Holdings Limited | Financial services | 2018 |
| Airhop New Site 1 Limited | Arts & recreation | 2023 |
| Airhop New Site 2 Limited | Arts & recreation | 2024 |
| Airhop New Site 3 Limited | Arts & recreation | 2024 |
| Airhop New Site 4 Limited | Arts & recreation | 2024 |
| Airhop New Site 5 Limited | Arts & recreation | 2024 |
| Airington Property Investment Limited | Real estate | 2022 |
| Airlie Matilda Limited | Information & communication | 2012 |
| Airliec Ltd | Construction | 2026 |
| Airmec (H2O) Limited | Water & waste | 2003 |
| Airport Tavern Limited | Hospitality | 2010 |
| Airport Taxis Bristol Ltd | Information & communication | 2024 |
| Airporttaxiexpress Limited | Transport & logistics | 2025 |
| Airrevo Limited | Professional & scientific | 2023 |
| Airsat (Construction) Ltd | Construction | 2021 |
| Airsat Properties Ltd | Real estate | 2011 |
| Airsat Real Estate Ltd | Real estate | 2018 |
| Airscream 313 Holdings Limited | Financial services | 2022 |
| Airscream UK Limited | Wholesale & retail | 2018 |
| Airsec Group Limited | Administrative & support | 2020 |
| Airsec Training Limited | Wholesale & retail | 2021 |
| Airstream Line Events Limited | Hospitality | 2016 |
| Airtech South West Limited | Manufacturing | 2018 |
| Airtight Media Ltd. | Professional & scientific | 2021 |
| Airway Medical Global Ltd | Manufacturing | 2025 |
| Airway Medical Ltd | Manufacturing | 2017 |
| Airwell Limited | Real estate | 2018 |
| Airy Limited | Information & communication | 2021 |
| Aisa Retirement Planning LLP | | 2013 |
| Aishu Retail Ltd | Wholesale & retail | 2025 |
| Aisis Limited | Professional & scientific | 2000 |
| Aisist Ltd | Construction | 2024 |
| Aisling Renewables Ltd | Energy | 2019 |
| Aispire UK Ltd | Information & communication | 2021 |
| Aisè Clothing Ltd | Wholesale & retail | 2024 |
| Aiter Ltd | Information & communication | 2017 |
| Aithal Property Ltd | Real estate | 2025 |
| Aithir Ltd | Information & communication | 2026 |
| Aithom Investments Ltd | Administrative & support | 2013 |
| Aithom Limited | Real estate | 2010 |
| Aitken Consultancy and Research Services Limited | Professional & scientific | 1998 |
| Aitken Joints Ltd | Health & social care | 2019 |
| Aitural Limited | Administrative & support | 2024 |
| AIU Global Investments Ltd | Financial services | 2025 |
| AIU Holdings Ltd | Financial services | 2022 |
| AIU Property Investments Ltd | Real estate | 2022 |
| Aivaluelab Limited | Information & communication | 2026 |