| Aisymmetrix Ltd | Cardiff | 2018 |
| AIT Accountants Limited | Solihull | 2003 |
| AIT Building Consultancy Limited | Stoke-On-Trent | 2026 |
| AIT Business Solutions Limited | Solihull | 2017 |
| AIT Consultancy Services Ltd | Reading | 2023 |
| AIT Management Ltd | Rotherham | 2018 |
| AIT Umbrella Limited | Poole | 2017 |
| Aita Ltd | Ilford | 2020 |
| Aitam Services Ltd | London | 2011 |
| Aitastic Ltd | London | 2024 |
| Aitch & Co Limited | Sheffield | 2011 |
| Aitch Aerospace Limited | Rhyl | 2008 |
| Aitch Consulting Limited | London | 2009 |
| Aitch Pharma Ltd | Wigan | 2022 |
| Aitch TEE Consulting Limited | Warrington | 2020 |
| Aitchco Ltd | Harrogate | 2018 |
| Aitcheson Hammond RRM Ltd | Bournemouth | 2025 |
| Aitchison & Colegrave Trustees Limited | Edinburgh | 1995 |
| Aitchison Associates Limited | Lancing | 2001 |
| Aitchison Consulting Ltd | Bolton | 2024 |
| Aitchison Cost Consultants Ltd | Birmingham | 2022 |
| Aitchison Evans Consulting Limited | Oxford | 2025 |
| Aitchison Group Ltd | Essex, Ilford | 2022 |
| Aitchison Meade Ltd | Gourock | 2023 |
| Aite Architecture Ltd | Hexham | 2024 |
| Aitec Limited | Bradford | 2015 |
| Aitekit Ltd | London | 2024 |
| Aiten Finance Limited | Surrey | 2014 |
| Aiteo Consulting Limited | Maidstone | 2006 |
| Aith (UK) Limited | Tynemouth | 2002 |
| Aith Consulting Limited | London | 2024 |
| Aithlaz Limited | Hounslow | 2025 |
| Aithra Limited | Cheltenham | 2018 |
| Aiti Solutions UK Ltd | London | 2021 |
| Aitimestech Ltd | London | 2025 |
| Aitken Accountancy Solutions Ltd | Birmingham | 2014 |
| Aitken Commercial Development Limited | Bury | 2010 |
| Aitken Consultancy and Coaching Limited | Edinburgh | 2014 |
| Aitken Consultancy and Research Services Limited | Bristol | 1998 |
| Aitken Consulting Ltd | Warrington | 2022 |
| Aitken Contract Solutions Limited | Edgware | 2018 |
| Aitken Corporate Consulting Limited | By West Calder | 1995 |
| Aitken Engineering Services Ltd | Tewkesbury | 2018 |
| Aitken Laboratories Limited | Edinburgh | 1986 |
| Aitken Macdonald Ltd | Purley | 2026 |
| Aitken Professional Services Limited | Kinross | 2013 |
| Aitken Property Consultancy Limited | Leven | 2022 |
| Aitken Retail Ltd | London | 2015 |
| Aitken Spencer Ltd. | Harrow | 2014 |
| Aitken Studio Ltd | Liverpool | 2024 |
| Aitken Turnbull Architects Limited | Kelso | 2003 |
| Aitkens Media Ltd | Oakham | 2014 |
| Aitnik Consultancy Limited | York | 2024 |
| Aito Capital Ltd | London | 2020 |
| Aiton Douglas Ltd | Torquay | 2023 |
| Aitsa Limited | Woking | 2011 |
| AIU Consultants Limited | Wembley | 2023 |
| AIU Partners Ltd | Birmingham | 2024 |
| AIU Services Ltd | Altrincham | 2022 |
| Aiudi Events Limited | London | 2018 |
| Aiuto Ltd | Cirencester | 2009 |
| Aiuz PLC | London | 2025 |
| AIV Limited | Carshalton | 2023 |
| Aiva Services Group Ltd | Penzance | 2026 |
| Aiva Studios Ltd | Blackburn | 2025 |
| Aivana Limited | Wilmslow | 2023 |
| Aivanta Automation Ltd | London | 2026 |
| Aivars Architects Limited | London | 2003 |
| Aiveen Interiors Ltd. | Worcester | 2007 |
| Aiver Ltd | Bathgate | 2017 |
| Aivex Ltd | London | 2026 |
| Aivia Systems Ltd | London | 2026 |
| Aiviko Ltd | London | 2012 |
| Aivilo Digital Accountancy Limited | Thatcham | 2022 |
| Aiviq Limited | London | 2018 |
| Aivivo Ltd | Cambridge | 2017 |
| Aivlom Creative Ltd | West Midlands | 2006 |
| Aivt Consulting Ltd | Stockport | 2025 |
| Aivyla Cole Ltd | Guildford | 2022 |
| AIW Business Solutions Limited | Towcester | 2023 |
| AIW Energy Assessors Ltd | Chelmsford | 2011 |
| AIW Legal Services Limited | London | 2018 |
| AIW QS Solutions Ltd | Sunderland | 2026 |
| AIW Services Limited | Hull | 2025 |
| Aiwa Communications Ltd | Ramsgate | 2025 |
| Aiwa Environmental Solutions Ltd | Hornchurch | 2016 |
| AIX Capital Holdings Ltd | Westminister | 2021 |
| AIX Capital Partners Ltd | London | 2025 |
| AIX Consultancy Limited | Royston | 2016 |
| AIX Ltd | High Wycombe | 2025 |
| AIX Partners Ltd | Southport | 2026 |
| Aixhumans Ltd | Corby | 2025 |
| Aixial Group UK Limited | Horsham | 2001 |
| Aixial UK Limited | Horsham | 1999 |
| Aixila Ltd | Shepperton | 2026 |
| Aixiliary Ltd | Edinburgh | 2026 |
| Aixist Limited | Arthog | 2024 |
| Aixkm Ltd | New Malden | 2026 |
| AIXON360 Limited | London | 2026 |
| Aixtra Limited | Bath | 2008 |