| Aims Financial Services Limited | Hayes | 2016 |
| Aims Holdings Limited | Chesterfield | 2023 |
| Aims Holdings NO. 1 Limited | London | 1998 |
| Aims Holdings NO. 2 Limited | London | 1998 |
| AIMS4LIFE Ltd | Cirencester | 2017 |
| Aimtech Group Holdings Ltd | Kettering | 2024 |
| Aimtila Limited | Edinburgh | 2026 |
| Ainad Capital Partners Ltd | London | 2026 |
| Ainfinite Ltd | Bradford | 2025 |
| Ainigma Holdings Ltd | Rickmansworth | 2020 |
| Ainleys Insurance Brokers (Ossett) Limited | Ossett | 2009 |
| Ainnov Tech Ltd | London | 2025 |
| Ainscough Holdings Limited | London | 2006 |
| Ainsdale Finance Limited | London | 2002 |
| Ainsley Asphalt Holdings Ltd | Nottingham | 2026 |
| Ainsley Holdings Limited | Manchester | 2022 |
| Ainslie Management Holdings Limited | London | 2025 |
| Ainslieco Limited | Fareham | 2023 |
| Ainsty Limited | Leeds | 2021 |
| Ainsworth Country Holdings Ltd | Walsall | 2020 |
| Ainsworth Family Holdings Ltd | Penrith | 2024 |
| Ainsworth Mortgages Limited | Wirral | 2005 |
| Ainsworth Print & Design Holdings Ltd | Stockport | 2025 |
| Ainsworth Road Holding Limited | Bury | 2017 |
| Aintree Canal Boat (Holdings) Ltd | Crosby | 2014 |
| Aintree Holdings (Dudley) Limited | Wolverhampton | 2025 |
| Aintree Holdings Ltd | Portsmouth | 2021 |
| AIO Lawpartners (AIO Legal Services) Limited | Luton | 2020 |
| AIO Ventures Limited | London | 2025 |
| Aiof II European Holdings Limited | London | 2022 |
| Aiof III Credit Holdings Limited | London | 2024 |
| Aioi Nissay Dowa Europe Limited | London | 2017 |
| Aioi Nissay Dowa Insurance Management Limited | London | 1985 |
| Aioi Nissay Dowa Insurance UK Limited | London | 2017 |
| Aion Bidco Limited | Guildford | 2022 |
| Aion Holdco Limited | Guildford | 2022 |
| Aion Holdings Ltd | Tamworth | 2026 |
| Aion Midco Limited | Guildford | 2022 |
| Aion Succession Partners Ltd | London | 2025 |
| Aion Topco Limited | Guildford | 2022 |
| Aion Ventures Limited | London | 2025 |
| Aiona Ltd | London | 2025 |
| Aionia Wealth Management Ltd | London | 2025 |
| Aionios Group Ltd | Bolton | 2025 |
| AIP Acquisitions II Limited | Reading | 2015 |
| AIP Acquisitions III Limited | Reading | 2016 |
| AIP Acquisitions VI Limited | Reading | 2019 |
| AIP Acquisitions VII Limited | London | 2021 |
| AIP Ardenham Holding 1 (UK) Ltd | Swanley | 2025 |
| AIP Ardenham Holding 2 (UK) Ltd | Swanley | 2025 |
| AIP CB2 Holding (UK) Ltd | Swanley | 2025 |
| AIP Co-Invest Marbles Limited | London | 2021 |
| AIP Financial Services Limited | Erith | 2018 |
| AIP Holdco Ltd | London | 2026 |
| AIP Holdings Limited | Reading | 2014 |
| AIP IV Limited | London | 2017 |
| AIP Mortgages Ltd | Blandford Forum | 2020 |
| AIP Solco Limited | London | 2018 |
| AIP UK Leaseco I Limited | London | 2026 |
| AIP UK Leaseco II Limited | London | 2026 |
| AIP UK Leaseco III Limited | London | 2026 |
| AIP V Limited | London | 2018 |
| AIP VI Limited | London | 2018 |
| AIP Wealth Management Limited | Manchester | 2016 |
| Aipchain Ltd | London | 2025 |
| Air (UK) HQ Ltd | Manchester | 2019 |
| Air Bidco Limited | Birmingham | 2014 |
| Air Buildings Limited | Derby | 2005 |
| Air Cair Holdings Limited | Norwich | 2016 |
| Air Capital Group Ltd | Longfield | 2025 |
| Air Capital Partners Limited | London | 2025 |
| Air Charter Service Group Limited | Surbiton | 2000 |
| Air Conditioning Design EOT Limited | Manchester | 2023 |
| Air Conditioning Hire Limited | Epsom | 2013 |
| Air Design Systems (Holdings) Limited | Gateshead | 2018 |
| Air Ducts (Southern) Holdings Limited | Aldershot | 2025 |
| Air Fuel Synthesis Holdings Limited | London | 2013 |
| Air Global International Holdings Limited | London | 2022 |
| Air Group Holdings Ltd | London | 2025 |
| Air Group Investments Limited | Stone | 2014 |
| Air Insight Limited | Derby | 2025 |
| Air Investment Group Ltd | Watford | 2021 |
| Air Power Products Group Limited | Sheffield | 2026 |
| Air Rescue Group Ltd | Telford | 2025 |
| Air RS Holdings Ltd | St. Albans | 2026 |
| Air Seating Group Limited | Kingswinford | 2023 |
| Air Star Limited | Maidstone | 2017 |
| Air Strategy Ltd | Sidcup | 2022 |
| Air Taxi Group Limited | Alexandria | 2022 |
| Air Temp Holdings Limited | Hull | 2020 |
| Air Track Holdings Limited | Leeds | 2023 |
| Air Trade Capital Ltd | London | 2025 |
| Air Water Investments Limited | Hawarden | 2021 |
| Air Works Aviation Services UK Limited | Norwich | 2018 |
| Air-Concepts UK Ltd | London | 2025 |
| Air-Line Systems Holdings Limited | Ashford | 2015 |
| Aira Force 2026-1 Holdings Ltd | London | 2026 |
| Aira Force 2026-1 PLC | London | 2026 |
| Airbag Team Holdings Limited | Coventry | 2023 |
| Airband Topco Limited | Droitwich | 2021 |