| Agatha Bagatha Limited | Belfast | 2013 |
| Agatha Christie Limited | London | 1955 |
| Agatha Ltd | Bolton | 2021 |
| Agathe B. Yoga Ltd | London | 2026 |
| Agatte Ltd | Telford | 2020 |
| Agavriloaiei Limited | Lincoln | 2023 |
| Agaw Limited | Chestefield | 2025 |
| Agawise Ltd | Porthcawl | 2013 |
| AGB Advertising Ltd | London | 2021 |
| AGB Bangor BID | Bangor | 2015 |
| AGB Beauty Nail Therapy Limited | Nottingham | 2018 |
| AGB Equestrian Ltd | Castle Eden | 2025 |
| AGB Holdings (South Wales) Ltd | Newport | 2024 |
| AGB Inc Ltd | London | 2025 |
| AGB Services(Leeds) Ltd | Leeds | 2005 |
| AGB Survey Solutions Limited | Inverurie | 2019 |
| Agba Painters Ltd | London | 2017 |
| Agbd Ltd | London | 2025 |
| AGC (Commodity Store) Limited | Tonbridge | 1986 |
| AGC Collective Actions Limited | London | 2025 |
| AGC Home Limited | London | 2022 |
| AGC1874 Limited | Birmingham | 2025 |
| Agct Holdings Limited | Saundersfoot | 2020 |
| AGD Cockermouth Ltd | Workington | 2026 |
| AGD Driving Services Ltd | Ilford | 2019 |
| AGD Glazing Ltd | Dartford | 2025 |
| Agdg Ltd | Haverhill | 2019 |
| AGE Concern Bromley | Bromley | 1997 |
| AGE Concern Cheshire | Northwich | 2002 |
| AGE Concern Durham County | Durham | 2007 |
| AGE Concern Durham County Trading Limited | Durham | 1996 |
| AGE Concern Eastwood | Glasgow | 1998 |
| AGE Concern Gloucestershire | Gloucester | 2005 |
| AGE Concern Hampshire Corporate Trustee Limited | Southampton | 2013 |
| AGE Concern Morgannwg Limited | Aberdare | 2008 |
| AGE Concern Peterborough | Cambridgeshire | 2000 |
| AGE Concern Wandsworth | | 1998 |
| AGE Connects Cardiff and the Vale Ltd | Cardiff | 2010 |
| AGE Gracefully Aesthetics Ltd | Glasgow | 2022 |
| AGE Less Aesthetics Ltd | Wallsend | 2015 |
| AGE NO Barrier Ltd | London | 2018 |
| AGE Project Consultancy Ltd | Inverurie | 2018 |
| AGE Scotland Orkney | Kirkwall | 2003 |
| AGE UK Bolton Enterprises Limited | Bolton | 1994 |
| AGE UK Coventry and Warwickshire | Leamington Spa | 2001 |
| AGE UK Enfield | Enfield | 1997 |
| AGE UK Hertfordshire Trading Limited | Hertford | 1994 |
| AGE UK Lincolnshire | Lincoln | 1999 |
| AGE UK Merton | Surrey | 2004 |
| AGE UK Newcastle Limited | North Shields | 2021 |
| AGE UK North of Tyne Ltd | North Shields | 2019 |
| AGE UK Oldham Limited | Oldham | 2010 |
| AGE UK Portsmouth | Hampshire | 1996 |
| AGE UK Services Limited | London | 2009 |
| AGE UK South East London Trading Ltd | Bromley | 1993 |
| AGE UK South Gloucestershire Enterprises Ltd | Bristol | 2016 |
| AGE UK South Gloucestershire Ltd | Bristol | 2005 |
| AGE UK Suffolk | Leicester | 2001 |
| AGE UK Tyneside Ltd | Bristol | 2018 |
| AGE United Limited | London | 2019 |
| AGE Well Aesthetics Ltd | Belfast | 2023 |
| AGE Well Hwyliog MON | Llangefni | 2013 |
| AGE With Pride Community Interest Company | Solihull | 2016 |
| Ageaham Limited | Wigan | 2018 |
| Ageless Aesthetics by Alexa Ltd | Ross-On-Wye | 2024 |
| Ageless Beauty Aesthetics Limited | Oxford | 2023 |
| Agelessperfectionaesthetic Ltd | Wolverhampton | 2024 |
| Agelgil Ltd | London | 2020 |
| Agem Events Ltd | London | 2015 |
| Agemo Furniture Ltd | Barnstaple | 2019 |
| Agemo UK Ltd. | London | 2008 |
| Agena Group Bidco Ltd | Polegate | 2019 |
| Agena Group Ltd | Polegate | 2019 |
| Agena Group Midco 1 Ltd | Polegate | 2019 |
| Agena Group Midco 2 Ltd | Polegate | 2019 |
| Agency AID CIC | High Wycombe | 2024 |
| Agency Assistance Day Care Limited | Exmouth | 2022 |
| Agency Brazil Limited | London | 2003 |
| Agency Hair Ltd | Belfast | 2026 |
| Agency Management Ltd | Tring | 2001 |
| Agency Recruitment Alliance Ltd | Newton-Le-Willows | 2026 |
| Agency Signs Limited | Newmarket | 1998 |
| Agency Supplies Ltd | Kingswinford | 2017 |
| Agencyland Network Ltd | Waterlooville | 2024 |
| Agencynomics Limited | London | 2015 |
| Agenda 2063 Gender Action Ltd | South Croydon | 2025 |
| Agenomicsphd Limited | Sudbury | 2024 |
| Agent PR Limited | Sheffield | 2013 |
| Agent Sempah Limited | London | 2026 |
| Agenta Ltd. | Ilkley | 2018 |
| Agentbuild Limited | Edinburgh | 1990 |
| Agente Legalis Limited | Wembley | 2019 |
| Agentic Cyber Solutions Ltd. | London | 2025 |
| Agents Management Ltd | London | 2025 |
| Agents Together 2.0 Limited | Grantham | 2025 |
| Agertoft Auto Ltd | London | 2025 |
| AGF Sport and Fitness Ltd | Stirling | 2018 |
| Agfabs Limited | Keighley | 2025 |
| AGG Capital Management (Holdco) Limited | Manchester | 2019 |
| AGG International Limited | Gourock | 2017 |