| Active Innovations Investments Limited | Bournemouth | 2017 |
| Active International Business Management Limited | Liverpool | 2015 |
| Active Keyholding Limited | Maidenhead | 2009 |
| Active Locksmiths Limited | Maidenhead | 2006 |
| Active Logistics (UK) Limited | Tipton | 2014 |
| Active Mechanical Services Limited | Darvel | 2008 |
| Active Online Marketing Technologies Ltd | Hove | 2010 |
| Active Plumbers Limited | Maidenhead | 2007 |
| Active Plumbing Supplies Limited | Bumpers Farm | 2009 |
| Active Polaris Ltd | Bury St. Edmunds | 2020 |
| Active Property Care Ltd | Feltham | 2005 |
| Active Property Maintenance Limited | Maidenhead | 2009 |
| Active Remedial Solutions Limited | Loughborough | 1998 |
| Active Security & Fire Limited | Maidenhead | 2007 |
| Active Security and Locksmiths Limited | Maidenhead | 2006 |
| Active Security Ltd | Maidenhead | 2005 |
| Active Studios Limited | London | 2014 |
| Active Talent Management Limited | London | 2014 |
| Active Workplace Solutions Ltd | Woodley | 2018 |
| Activeled Ltd | Haywards Heath | 2005 |
| Activenet Limited | Burton On Trent | 2015 |
| Activity Business Cover Ltd | London | 2021 |
| Activity Holdings Ltd | Norwich | 2023 |
| Activity Hunter Ltd | Newquay | 2016 |
| Activity Nation Ltd | London | 2021 |
| Actmask Group Co., Ltd | Cambridge | 2013 |
| Actnow Coaching Ltd | Stroud | 2024 |
| Actons Limited | Leicestershire | 1995 |
| Actons Restaurant Limited | Belfast | 1985 |
| Actors Plus Ltd | London | 2017 |
| Acts International Ltd | Billingshurst | 2015 |
| Actual Cleaning Co. Limited(The) | Hornchurch | 1974 |
| Actual Consulting Ltd | Wokingham | 2014 |
| Actual Group Limited | Hornchurch | 2018 |
| Actual Removal Company Ltd | Hornchurch | 1988 |
| Actuality 360 Limited | Poole | 2024 |
| Actuatus Systems Ltd | Bristol | 2023 |
| Actv Sports Ltd | Grangemouth | 2018 |
| ACU Medical Services Ltd | Macclesfield | 2024 |
| Acuity Advisors Employee Trustee Limited | London | 2020 |
| Acuity Contact Lenses Limited | Waltham Cross | 2007 |
| Acuity Ultrasonics Limited | Rhyl | 2018 |
| Acuity Unified Communications Limited | Coulsdon | 2010 |
| Acumen Automotive Limited | Swan Valley | 1963 |
| Acumen Distribution Services Holdings Limited | Warrington | 1997 |
| Acupaq Limited | Bury St. Edmunds | 2016 |
| Acute Recruit Ltd | Chorley | 2021 |
| Acute Sales Limited | Newbury | 2016 |
| Acutest Test Instrument Specialists Limited | Newbury | 2004 |
| Acuti Associates Ltd | London | 2022 |
| ACW UK Corporate Limited | London | 2020 |
| ACY Cosmetics Holding Limited | Manchester | 2020 |
| ACY KOI Ltd | Wellingborough | 2021 |
| Aczel Limited | Llandudno | 2023 |
| AD Contractors Ltd | Lincoln | 2010 |
| AD Development Projects Limited | Sidcup | 2006 |
| AD Diagnostics Limited | Buckingham | 2025 |
| AD Engitech Limited | Basingstoke | 2023 |
| AD FAB Media Limited | London | 2009 |
| AD HOK Ltd | Harrogate | 2012 |
| AD Home Catering Limited | London | 2025 |
| AD International Trading Co., Ltd | London | 2018 |
| AD Joinery Services Ltd | Ilkeston | 2019 |
| AD Lettings Limited | Basingstoke | 2024 |
| AD Maiora Consulting Ltd | Bath | 2018 |
| AD Mobile Services Ltd | Coventry | 2016 |
| AD Quality UK Limited | London | 2006 |
| AD Valorem Company Secretarial Limited | Milton Keynes | 2001 |
| AD Valorem Limited | Milton Keynes | 2022 |
| Ad's Online Retail Limited | Leicester | 2020 |
| Ad-Bench U.K. Limited | Driffield | 1995 |
| Ad-Chem Limited | Shifnal | 1983 |
| Ad-Lee Trading Co Ltd | South Kirkby | 2014 |
| Ad-Rains Limited | Chippenham | 2008 |
| AD4M Limited | Harrogate | 2018 |
| ADA Food Centre Ltd | Waltham Abbey | 2016 |
| ADA International Trading Ltd | Cardiff | 2016 |
| ADA Mortgages Ltd | Sheffield | 2024 |
| ADA Panayi Ltd | Northfleet | 2024 |
| ADA Tang Bishopbriggs Limited | Glasgow | 2011 |
| ADA Valeria Tebeni Ltd | Elgin | 2024 |
| Adair Paxton Estate Agents Limited | Horsforth | 2015 |
| Adal Construction Ltd | London | 2017 |
| Adalliance Co. Ltd | London | 2024 |
| Adalta Real Limited | Banbury | 2012 |
| Adam Alexander Spencer Ltd | Ilford | 2024 |
| Adam Architecture (International) Limited | Winchester | 1988 |
| Adam Building Services Limited | London | 2006 |
| Adam Collier Funeral Services Ltd | Pickering | 2014 |
| Adam Designs IT Ltd | Torquay | 2019 |
| Adam Dumrul Ltd | Peterborough | 2025 |
| Adam Elektro Invest Limited | London | 2025 |
| Adam Elektro Limited | London | 2025 |
| Adam Ellis Saddles Limited | Walsall | 2020 |
| Adam Fire Surrounds Limited | Huddersfield | 2003 |
| Adam Harford Limited | Chester-Le-Street | 2019 |
| Adam James Dawson Limited | Manchester | 2024 |
| Adam James Willett Limited | Cambridge | 2024 |
| Adam Julian Marshall Ltd | Lincoln | 2024 |
| Adam Mario Khan-Dessi Ltd | Leeds | 2022 |