| Agaru Clothing Limited | Liverpool | 2024 |
| Agasthi Siddha Private Limited | Hornchurch | 2024 |
| Agastia Limited | Solihull | 2020 |
| Agata Marvelous General Trading Ltd | London | 2024 |
| Agata Naturals Ltd | Livingston | 2024 |
| Agatar Limited | Morecambe | 1993 |
| Agate Material Handling Ltd | Blandford Forum | 2023 |
| Agate Products Limited | London | 1946 |
| Agatka Limited | Brighton | 2009 |
| AGB Electrical Ltd | Northwich | 2012 |
| AGB Narib Limited | Stotfold Hitchin | 1963 |
| AGB Services Anglia Limited | Colchester | 2013 |
| AGB Swimming Pools Limited | Colchester | 2025 |
| Agb-Tech Ltd | Manchester | 2016 |
| Agbekeartistry Limited | Nottingham | 2025 |
| Agbr Ltd | Barnard Castle | 2021 |
| AGC Build (SY) Ltd | Welshpool | 2026 |
| AGC Carpentry Limited | Hertford | 2020 |
| AGC Chemicals Europe, Ltd. | Thornton-Cleveleys | 1999 |
| AGC Electrical Ltd | Exmouth | 2009 |
| AGC Fabrications Limited | Hatton | 2014 |
| AGC Glass UK Ltd | Northampton | 1990 |
| AGC Steel Limited | Belfast | 2025 |
| Agchem Buyers Limited | Wakefield | 2020 |
| Agco Limited | Kenilworth | 1952 |
| AGD Carpentry Ltd | Ely | 2025 |
| AGD Design Ltd | Brighton | 2022 |
| AGD Europe Ltd | Market Harborough | 2013 |
| AGD Innovations Ltd | Craigavon | 2025 |
| AGD Systems Limited | Cheltenham | 1991 |
| AGE Care Maintenance Ltd | Chesterfield | 2024 |
| AGE of Innocence Limited | London | 2016 |
| AGE Over Ltd | London | 2023 |
| AGE Reversal Europe Ltd. | East Saltoun | 1994 |
| Aged to Perfection Upholstery (Scotland) Ltd | Livingston | 2022 |
| Aged to Perfection Upholstery Limited | Burnley | 2013 |
| Agee Engineering Ltd | Brentwood | 2019 |
| Ageek MSP PCB Ltd | Chesterfield | 2021 |
| Ageek PCB Techserv Ltd | Chesterfield | 2017 |
| Ageing Limited | Glasgow | 2022 |
| Ageless Alchemist Ltd | Barnsley | 2025 |
| Ageless Beauty Group Limited | West Midlands | 2023 |
| Ageless Innovation UK Limited | London | 2018 |
| Ageless Science Limited | London | 2025 |
| Ageltec Limited | Harlow | 2002 |
| Agema Engineering Limited | Coventry | 1986 |
| Agemaspark Holdings Limited | Doncaster | 2017 |
| Agemaspark Ltd | Doncaster | 2002 |
| Agency and General Investment Co. Limited | Bromley | 1973 |
| Agency Shop Ltd | Barking | 1999 |
| Agencytech Ltd | Amersham | 2025 |
| Agenda (UK) Limited | Farnham | 2006 |
| Agenda Boxes & Packaging Ltd | Nelson | 2015 |
| Agenda International Limited | London | 2003 |
| Agent Glow Ltd | London | 2023 |
| Agent Labs Ltd | London | 2026 |
| Agent Print Limited | Oxford | 1996 |
| Agent Smith Chemicals Ltd | Winsford | 2018 |
| Agent-At-Large Limited | London | 2020 |
| Agentdraw Holdings Limited | Leicester | 2017 |
| Agentdraw Limited | Leicester | 1991 |
| Agentdraw Manufacturing Limited | Leicester | 2016 |
| Agentic Capital Limited | Hadleigh | 2020 |
| Agentlease Ltd | Altrincham | 2026 |
| Ageref Refrigeration Services Limited | Blaby | 2014 |
| Ageus Technology Limited | Wirral | 2002 |
| Ageya Limited | Sheffield | 2024 |
| AGF Foods Limited | Newcastle | 2020 |
| AGF Steels Ltd | Manchester | 2024 |
| Agfa IJC Limited | Cambridge | 2015 |
| Agform Limited | Leeds | 2000 |
| Agform Technologies Limited | London | 2018 |
| AGG Garage Doors Ltd | Sandhurst | 2015 |
| AGG UK Limited | London | 2009 |
| Agg-Fix Maintenance Limited | Newport | 2019 |
| Aggcycle Engineering Ltd | Craigavon | 2026 |
| Aggiari Coffee Company Ltd | London | 2024 |
| Aggies Contract Services Ltd | Ballymena | 2024 |
| Agglite Limited | Worksop | 2013 |
| Agglomerate Technologies Ltd | Birmingham | 2025 |
| Aggniko Ltd | London | 2024 |
| Aggo Ltd | Birmingham | 2022 |
| Aggre One Ltd | Doncaster | 2019 |
| Aggregate Processing and Recycling Limited | Cambridge | 1996 |
| Aggregate Remade Ltd. | Beith | 2013 |
| AGH Aircraft Engineering Ltd | Gloucester | 2023 |
| AGH Elecs Limited | Brighton | 2025 |
| Agha Beauty Ltd | London | 2025 |
| Aghora Wellness Ltd | London | 2023 |
| AGI Vehicles Ltd | London | 2025 |
| AGI World Limited | London | 1969 |
| Agia Industries Ltd | Kingsbridge | 2024 |
| Agie Sagie Ltd | Harrow | 2019 |
| Agilbility Limited | Glasgow | 2019 |
| Agile Carpentry Ltd | Southampton | 2018 |
| Agile Clarity Limited | Bucks | 1984 |
| Agile Engineering Ltd | Bourne | 2024 |
| Agile Maintenance Solutions Limited | Wolverhampton | 2024 |
| Agile Manufacturing Power Systems Ltd | Nottingham | 2021 |
| Agile Medical Ltd | Grimsby | 2017 |