| ACS Group Inc Limited | Washington | 2011 |
| ACS Group Limited | Newport | 2008 |
| ACS Learning & Consultancy Ltd | Kilmacolm | 2015 |
| ACS Legal Limited | Maidstone | 2013 |
| ACS Liberty Group UK Ltd | Teddington | 2015 |
| ACS Management Services Ltd | London | 2020 |
| ACS Motorsport UK Limited | Hungerford | 2022 |
| ACS North West Ltd | Brierley Hill | 2021 |
| ACS Nuclear Safety Limited | Cockermouth | 2019 |
| ACS Oakdale Limited | Newport | 2025 |
| ACS Paws Ltd | Norwich | 2024 |
| ACS Performance Improvement Limited | Chichester | 2006 |
| ACS Photography Ltd | Bushey | 2025 |
| ACS Physical Risk Control Limited | Cardiff | 2006 |
| ACS Ports Services Ltd | Portsmouth | 2024 |
| ACS Procurement Limited | London | 2022 |
| ACS Projects Limited | Washington | 2003 |
| ACS Property Investments Limited | Wembley | 1999 |
| ACS Refrigeration Installation Ltd | Hamilton | 2021 |
| ACS Safety & Security Ltd | London | 2014 |
| ACS Skillsassessment Limited | London | 2025 |
| ACS Synergy Limited | St. Albans | 2024 |
| ACS Technical Limited | | 2007 |
| ACS Testing Limited | Poole | 2003 |
| ACS Thermal Engineers Limited | Sale | 1990 |
| ACS Worldwide Ltd | Stoke-On-Trent | 2024 |
| Acs-Tech Limited | Coventry | 2014 |
| ACS4U Limited | Sale | 2008 |
| Acsa Consulting Ltd | Leighton Buzzard | 2026 |
| Acsana Ltd | London | 2026 |
| Acsciens Limited | Altrincham | 2025 |
| Acscott Consultants Limited | Chelmsford | 2019 |
| Acsel Ltd | London | 2024 |
| Acsi-Europe Ltd | Swindon | 1999 |
| Acsian Limited | Richmond | 2024 |
| Acsil Consulting Ltd | London | 2013 |
| Acsk Healthcare Ltd | Harrow | 2023 |
| Acsl Services Ltd | Kilmarnock | 2026 |
| Acsmid (Holdings) Limited | Elgin | 1997 |
| Acsoft Holdings Limited | Bedford | 2011 |
| Acsoft Limited | Bedford | 1993 |
| Acsp Ltd | Coalville | 2022 |
| Acssis Ltd | Norwich | 2016 |
| Acstro Limited | Llandeilo | 2008 |
| Acstrom Ltd | Manchester | 2026 |
| Acsu Limited | Hull | 2025 |
| Acsys Design Limited | Hampshire | 2007 |
| ACT & Achieve Ltd | Dover | 2021 |
| ACT 1.5 CIC | Bristol | 2024 |
| ACT 2 Consultants Limited | Motherwell | 2007 |
| ACT 2 Transform Ltd | York | 2016 |
| ACT 3D Limited | Bury St. Edmunds | 2026 |
| ACT 4 Displays Limited | Leicester | 2026 |
| ACT 4 Solutions Limited | Belfast | 2008 |
| ACT 5 Ventures UK Ltd | Weybridge | 2023 |
| ACT 74 Ltd | Saltburn-By-The-Sea | 2025 |
| ACT Accounting Limited | London | 2026 |
| ACT Acoustics Ltd | Truro | 2017 |
| ACT Architectural Design Services Ltd | Preston | 2020 |
| ACT Assist Ltd | Manchester | 2016 |
| ACT Blade Limited | Edinburgh | 2015 |
| ACT Building Compliance Ltd | Sheffield | 2026 |
| ACT Building Consultancy Ltd | Dartford | 2013 |
| ACT Building Control Limited | Manchester | 2005 |
| ACT Business Consultants Ltd | Didcot | 2016 |
| ACT Coaching and Consulting Ltd | Kingston Upon Thames | 2021 |
| ACT Construction Solutions Ltd | Loughton | 2023 |
| ACT Consultancy Services Ltd | Biggin Hill | 2011 |
| ACT Consulting Ltd | Thornton-Cleveleys | 2024 |
| ACT Creative Studio Ltd | London | 2016 |
| ACT Digital U.K. Limited | London | 2025 |
| ACT Electrical Services Ltd | Lowestoft | 2017 |
| ACT Energy Consulting Limited | Stockport | 2020 |
| ACT Enterprise Limited | London | 1998 |
| ACT Entertainment Ltd | Dagenham | 2023 |
| ACT Executive Limited | Harrow | 2012 |
| ACT Finance Limited | Leeds | 2011 |
| ACT Financial Consultancy Limited | London | 2019 |
| ACT Fire Consultancy Limited | Glasgow | 2011 |
| ACT Flooring Consultancy Limited | Cambridge | 2019 |
| ACT for Cancer Services Ltd | London | 2018 |
| ACT III Consulting Ltd | West Wickham | 2024 |
| ACT Investments Limited | Roxborough Way | 1951 |
| ACT IT Become IT Limited | London | 2023 |
| ACT Lean Ltd. | Altrincham | 2011 |
| ACT Local Ltd | Gloucester | 2023 |
| ACT Marketing Ltd | Crawley | 2014 |
| ACT Medical Ltd | Loughborough | 2021 |
| ACT METERS2U Limited | Rugeley | 2025 |
| ACT Naturally Ltd | | 2006 |
| ACT NOW Academy Limited | Tenby | 2023 |
| ACT NOW Consultancy Limited | Sale | 2012 |
| ACT NOW Energy Ltd | Liverpool | 2025 |
| ACT NOW for Business Ltd | Whitstable | 2020 |
| ACT NOW Team Development Ltd | Kenilworth | 2010 |
| ACT on Climate Ltd | Wells | 2016 |
| ACT on Consultancy Limited | Leamington Spa | 2023 |
| ACT on Fact Ltd | Biggin Hill | 2024 |
| ACT on Technology Limited | Acton | 2011 |
| ACT One Studio Limited | Tring | 2024 |