| Acre Farm Limited | Leek | 2001 |
| Acre Properties 2017 Limited | London | 2017 |
| Acre Somerset Limited | Yeovil | 2026 |
| Acre Wood Advisors Limited | London | 2023 |
| Acrecliffe Equichange CIC | Otley | 2024 |
| Acreedo Tattoos Limited | Abingdon | 2012 |
| Acres Way Dog Pound Limited | Dartford | 2008 |
| Acrew Limited | Bedford | 2015 |
| Acrocross Limited | Middlesex | 1989 |
| Acrom Construction Management Limited | North East Lincolnshire | 2005 |
| Acrometis Ltd | Norwich | 2017 |
| Acrometis Solutions Limited | Norwich | 2017 |
| Acropolis House of Style Limited | Staffordshire | 2003 |
| Acror Limited | London | 2020 |
| Across Borders Travel Ltd | London | 2024 |
| Across Rainbows C.I.C. | Brighton | 2020 |
| Across the Room Limited | Ipswich | 1994 |
| Across Town & Country Ltd | Chandlers Ford | 2023 |
| Acrusis Limited | Solihull | 2015 |
| Acrux Systems Limited | Manchester | 2022 |
| Acrylicbiab Ltd | London | 2026 |
| Acrylx Ltd | Middlewich | 2024 |
| ACS (NW) Ltd | Liverpool | 2016 |
| ACS Admin Limited | Horley | 2017 |
| ACS Autowerks Limited | Uxbridge | 2006 |
| ACS Barbers Limited | London | 2022 |
| ACS Cancer Ltd | London | 2018 |
| ACS Commercial Enterprises Limited | Cobham Surrey | 2017 |
| ACS Consultants Group Ltd | Ilford | 2017 |
| ACS Driving Ltd | Rugby | 2024 |
| ACS Engraving Limited | Kent | 2004 |
| ACS Inventories Ltd | Halifax | 2012 |
| ACS Investment (London) Limited | Hertford | 2025 |
| ACS Legal Consultancy Limited | Leigh On Sea | 2018 |
| ACS Security Ltd | Bradford | 2014 |
| Acsco Services Limited | Hyde | 2017 |
| Acsgholdings Ltd | West Wickham | 2025 |
| Acsis Life Coaching Ltd | Crowborough | 2024 |
| Acsmj Doncaster Limited | London | 2024 |
| Acsol Limited | Cheadle | 2007 |
| ACT (Administration) Limited | London | 1983 |
| ACT App Makers Limited | London | 2021 |
| ACT for Autism C.I.C. | Leamington Spa | 2018 |
| ACT NOW Health Coaching Ltd | Kington | 2023 |
| ACT NOW Limited | Belfast | 2023 |
| ACT on Dyslexia Ltd | Birmingham | 2015 |
| ACT One Script Clearance Ltd | London | 2024 |
| ACT Peer Recovery CIC | Lancaster | 2014 |
| ACT Pension Trustees Limited | London | 1982 |
| ACT Property Services (Cheshire) Ltd | Crewe | 2023 |
| ACT Rowles Property Limited | Crewkerne | 2000 |
| ACT Umbrella Limited | Ruislip, | 2024 |
| Acta Assist Limited | Bradford | 2020 |
| Acta FM Ltd | Chelmsford | 2021 |
| Actagility Limited | Croydon | 2008 |
| Actalent Services Limited | Bracknell | 2020 |
| Actasia | London | 2007 |
| Actfurniture Ltd | Hereford | 2020 |
| Actife Gents Hair Studio Limited | London | 2007 |
| Actin Time Ltd | Hertford | 2009 |
| Acting Action Limited | London | 2009 |
| Acting for Change Limited | Harrogate | 2004 |
| Action 4 Construction Training Ltd | Sutton In Ashfield | 2026 |
| Action 4 Equality (Scotland) Limited | Newcastle Upon Tyne | 2005 |
| Action Aerials Limited | Mansfield | 2011 |
| Action Against Abduction | London | 1999 |
| Action Against Carbon Capture and Storage Limited | Wirral | 2026 |
| Action Against Hunger Enterprises Limited | London | 2008 |
| Action Amps [Amputee Casualty Simulations] Limited | Cottingham | 2005 |
| Action CAM Limited | Hatfield | 2018 |
| Action Deaf Youth | Belfast | 2013 |
| Action Drains Limited | West Bromwich | 1994 |
| Action DRY Emergency Services Limited | Romford | 2003 |
| Action for Accountability Limited | London | 2025 |
| Action for Community Ltd. | Bradford | 2009 |
| Action for Community Transformation Initiative | Belfast | 2012 |
| Action for Construction Limited | Sutton-In-Ashfield | 2016 |
| Action for Kids Charitable Trust | London | 1997 |
| Action Graphics Ltd | Teddington | 2010 |
| Action Group Trustees Limited | London | 2023 |
| Action Health and Safety Services Limited | Whitefield | 2012 |
| Action Housing and Support Limited | Rotherham | 1981 |
| Action IT Support Limited | Hailsham | 2011 |
| Action Locksmiths Limited | Aylesbury | 2024 |
| Action Logic Ltd | London | 2015 |
| Action Motion Ltd | Osterley | 2017 |
| Action Motors Limited | Station Road | 1981 |
| Action of Churches Together in Scotland | Linlithgow | 2008 |
| Action on Blood Limited | Hornchurch | 2008 |
| Action on Postpartum Psychosis | London | 2010 |
| Action Performance Limited | London | 2018 |
| Action Recruitment (Wales) Limited | Swansea | 2009 |
| Action Renewables | Belfast | 2003 |
| Action Replay Records Limited | Milton Keynes | 1983 |
| Action Services (Hull) Ltd | Hull | 2012 |
| Action Skip Hire Ltd | Walsall | 2018 |
| Action Talks Limited | Faversham | 2018 |
| Action Training (ATL) Limited | Morley, Leeds | 2010 |
| Action With Communities in Rural England | Bristol | 1997 |
| ACTION3 Ltd | London | 2024 |