| ACS Security Solutions Ltd | Grays | 2022 |
| ACS (Blackburn) Limited | Burnley | 2001 |
| ACS 23 Ltd | London | 2023 |
| ACS Access and Maintenance Limited | Blackburn | 2010 |
| ACS Accident Claims Scotland Ltd | Paisley | 2017 |
| ACS Automotive Recruitment Consultancy Limited | Leigh-On-Sea | 2012 |
| ACS Ayrshire Cleaning Services Ltd | Lanark | 2023 |
| ACS Business Performance Ltd | Hove | 2007 |
| ACS Clean and Decs Ltd | Rochester | 2022 |
| ACS Cleaning (Hull) Limited | Warrington | 2017 |
| ACS Cleaning Ltd | Fleet | 2025 |
| ACS Cleaning Services Limited | Carlisle | 2002 |
| ACS Clearaway Limited | Rochester | 2026 |
| ACS Commercials Limited | Dover | 2024 |
| ACS Community Projects (ACS UK) Ltd | Durham | 2020 |
| ACS Consultants (UK) Ltd | Blackpool | 2014 |
| ACS Consulting Limited | Woodford Green | 2014 |
| ACS Consulting Services Limited | Canterbury | 2017 |
| ACS Control Systems Limited | Belfast | 1992 |
| ACS Corporate Management Limited | Darwen | 2014 |
| ACS Developments Homes Limited | Cottingham | 2017 |
| ACS Domestics Limited | Dover | 2023 |
| ACS Eccles Electrical Limited | Aberdeen | 2013 |
| ACS Employment Agency Ltd | Crosby | 2025 |
| ACS Energy Ltd | Irvine | 2021 |
| ACS Extreme Cleaning Limited | Plymouth | 2025 |
| ACS General Partner Limited | Winchester | 2013 |
| ACS Global Securities Limited | London | 2012 |
| ACS Groundworks Ltd | Stevenage | 2016 |
| ACS Group Management (UK) Limited | Bristol | 2025 |
| ACS Group Service Ltd | London | 2022 |
| ACS Industrial Limited | Berkhamsted | 2003 |
| ACS Legal Recruiting Ltd | Northallerton | 2025 |
| ACS Pressure Washing Ltd | Newton-Le-Willows | 2025 |
| ACS Recruitment Solutions Limited | Northampton | 2015 |
| ACS Residential Limited | Hampshire | 2008 |
| ACS Salisbury Ltd | Salisbury | 2021 |
| ACS Secure Limited | Crosby | 2025 |
| ACS Skip Hire Limited | Manchester | 2009 |
| ACS Specialist Cleaning Limited | Blackburn | 2005 |
| ACS Support Limited | Stockport | 2023 |
| ACS Trustees Limited | Barking | 2024 |
| ACS Utility Services Limited | Hatfield | 2017 |
| ACS Wind Care Limited | Belfast | 2013 |
| ACS Window Cleaning Limited | Southend-On-Sea | 2021 |
| ACS Works Ltd | London | 2024 |
| Acs-Fm Limited | Erith | 2013 |
| Acsa Pharm Ltd | Iver | 2017 |
| Acsafe Ltd | Clydebank | 2023 |
| Acsearle Advisory Ltd | Esher | 2025 |
| Acseu Ltd | Bolton | 2019 |
| Acsr Services Ltd | Northwich | 2020 |
| Acstar Limited | Weybridge | 2017 |
| Acsuk Co Ltd | Bolton | 2009 |
| ACT 2025 Holdings Ltd | Huddersfield | 2025 |
| ACT 4 Limited | London | 1998 |
| ACT Abrasives Limited | Kington | 2023 |
| ACT Alcohol Ltd | Worcester | 2018 |
| ACT Art Productions Limited | Manchester | 2021 |
| ACT Cleaning Services Limited | Surrey | 2003 |
| ACT Commercial Property Ltd | Knaresborough | 2019 |
| ACT Community Ltd | Pontyclun | 2023 |
| ACT Consultancy (UK) Limited | Barnet | 2022 |
| ACT Credit Management Limited | Harrow | 2004 |
| ACT Cycling Tours Ltd | Bury St Edmunds | 2013 |
| ACT Excel Limited | Middlesbrough | 2015 |
| ACT for Action Community Interest Company | Liverpool | 2018 |
| ACT for Impact Ltd | London | 2026 |
| ACT Housing Limited | York | 2016 |
| ACT HR Services & Consultancy Ltd | York | 2023 |
| ACT Industrial Cleaning Specialists Ltd | Seaham | 2016 |
| ACT Industrial Support Services Ltd | Seaham | 2024 |
| ACT Mortgage Management Investments Ltd | Beckenham | 2022 |
| ACT Mortgage Management Limited | Beckenham | 2005 |
| ACT One Training Services Ltd | Colchester | 2018 |
| ACT Personnel Ltd | London | 2024 |
| ACT Projects Ltd. | Newcastle Upon Tyne | 2002 |
| ACT Property Oxfordshire and Berkshire Limited | Cobham | 2020 |
| ACT Publishing UK Limited | Wrotham Heath | 1999 |
| ACT Response Ltd | Middlesbrough | 1998 |
| ACT Safeguard Limited | Middlesbrough | 2015 |
| ACT Safety Group Limited | Glasgow | 2016 |
| ACT Security Systems Limited | Romsey | 1998 |
| ACT to Change Limited | Ongar | 2007 |
| Act'In Theatre Ltd | London | 2021 |
| ACT*1 Services Limited | London | 2007 |
| Acta Marine UK Limited | Newcastle Upon Tyne | 2021 |
| Acta Medical Limited | Wallington | 2020 |
| Actaris Recruitment Limited | Barnet | 2013 |
| Actaris Site Services Limited | Barnet | 2017 |
| Actavis Holdings UK Ltd. | Castleford | 2004 |
| Actavo (Northern Ireland) Limited | Belfast | 2011 |
| Actavo Events (UK) Limited | Birmingham | 2010 |
| Actavo Holdings (UK) Limited | Birmingham | 2008 |
| Actc Coaching Limited | Wetherby | 2017 |
| Actech Recruitment Limited | Wilmslow | 2020 |
| Actek 2007 Limited | Lynmouth | 2007 |
| Actem Environmental Limited | Southam | 2024 |
| Acteon Middle East and FAR East Investments Limited | Norwich | 2007 |
| Acteon UK Financing Limited | Norwich | 2014 |