| Armour (Insurance Services) Limited | Barnet | 1961 |
| Armour Bidco Limited | Manchester | 2018 |
| Armour Group Land Sea Air Limited | Chelmsford | 2013 |
| Armour Hart Holdings Limited | Borough Green | 2022 |
| Armour Holdings Limited | Sunderland | 2019 |
| Armour Joinery Ltd | Oban | 2020 |
| Armour Life Ltd | Budleigh Salterton | 2019 |
| Armour Risk Management Limited | London | 2009 |
| Armourcoat Holdings Limited | Sevenoaks | 2018 |
| Armourcore Security Limited | London | 2024 |
| Armourgeddon Holdings Limited | Lutterworth | 2018 |
| Armours Holdings Ltd | Dagenham | 2024 |
| Armox Legacy Limited | Wantage | 2025 |
| Arms Alliance Limited | Swaffham | 2024 |
| Arms Locked Alliance Ltd | Manchester | 2025 |
| Arms Park Financial Services Limited | Caerphilly | 1995 |
| Arms United Limited | London | 2018 |
| Arms Ventures Limited | Worthing | 2023 |
| Armstad Asset Holdings Limited | London | 2026 |
| Armstrong & Capp Ltd | Stockport | 2019 |
| Armstrong 22 Ltd | Newcastle Upon Tyne | 2022 |
| Armstrong Advisory 2 Limited | London | 2019 |
| Armstrong and Butler Holdings Limited | London | 2018 |
| Armstrong and Butler Wembley Limited | London | 2018 |
| Armstrong Bardin Ltd | Cheltenham | 2010 |
| Armstrong Bidco Limited | Loughborough | 2018 |
| Armstrong Bridging International Limited | Cheltenham | 2016 |
| Armstrong Brokers Ltd | Stocksfield | 2019 |
| Armstrong Brooks Limited | Stockport | 1988 |
| Armstrong Brothers Holdings Limited | Dumfries | 2024 |
| Armstrong Capital Management Limited | Norwich | 2018 |
| Armstrong Cook Holdings Limited | Barnsley | 2026 |
| Armstrong France Holdings Limited | Taunton | 2011 |
| Armstrong Group (UK) 2023 Limited | Exhall | 2020 |
| Armstrong Group Limited | London | 2018 |
| Armstrong Group of Companies Limited | Lutterworth | 2020 |
| Armstrong Holdco Ltd | Dungannon | 2025 |
| Armstrong Infrastructure and Property Finance Limited | Norwich | 2016 |
| Armstrong International Capital Limited | London | 2024 |
| Armstrong Investment Capital Corporation Ltd | London | 2026 |
| Armstrong Investment Ventures Ltd | Peterborough | 2025 |
| Armstrong KER (Macclesfield) Limited | Wilmslow | 1995 |
| Armstrong Midco Limited | Loughborough | 2018 |
| Armstrong Mortgages Limited | Torpoint | 2025 |
| Armstrong Nationwide Ltd. | Chester Le Street | 2000 |
| Armstrong Priestley Holdings Limited | Leeds | 2016 |
| Armstrong Private Equity Ltd | Wilmslow | 2025 |
| Armstrong Procter Group Ltd | Tewkesbury | 2025 |
| Armstrong Property Ltd | Glasgow | 2019 |
| Armstrong Property Solutions Ltd | Bourne | 2025 |
| Armstrong Security Gaurds Limited | Ilford | 2022 |
| Armstrong Sub-Holdings Limited | Loughborough | 2018 |
| Armstrong Topco Limited | Loughborough | 2018 |
| Armstrong Watson Financial Planning Ltd | Carlisle | 2010 |
| Armstronger Group Ltd | Harrow | 2020 |
| Armstrongs Commercial Limited | Newcastle | 2013 |
| Armstrongs Group Limited | Coventry | 2025 |
| Armstrongs Mortgage Solutions Limited | Hinckley | 2024 |
| Armstrongs Wealth Planning Limited | Coventry | 2018 |
| Armultra Investments Limited | Great Yarmouth | 2022 |
| Armup Blockchain Financial Ltd | London | 2023 |
| Army Dependants Assurance Trust Limited | Chichester | 1973 |
| ARN Capital Group Ltd | Leeds | 2025 |
| ARN Financial Services Ltd | Manchester | 2026 |
| ARN Invest Ltd | Ruislip, | 2021 |
| Arna Investments Limited | London | 2020 |
| Arnau & Co. Ltd | London | 2022 |
| Arnco Capital Ltd | Barnet | 2022 |
| Arne Holdings Limited | Ringwood, Dorset | 2026 |
| Arnell Properties Holdings Limited | Tamworth | 2018 |
| Arnfield CQV Limited | Glossop | 2019 |
| Arni Services Limited | London | 2022 |
| Arnia Group Ltd | Birmingham | 2026 |
| Arnia Investment Company | Birkenhead | 2022 |
| Arnik Limited | Staines-Upon-Thames | 2016 |
| Arniston Finance Company Limited | Edinburgh | 2013 |
| Arniston Holdings Limited | Brackley | 2022 |
| Arniston Property Ltd | London | 2020 |
| Arno Commercial Solutions Ltd | Cardiff | 2023 |
| Arno UTG Limited | London | 2013 |
| Arnoco (SW) Ltd | Axminster | 2018 |
| Arnold & Arnold Holdings Limited | Liverpool | 2024 |
| Arnold & Co Ltd | Barnsley | 2007 |
| Arnold & Green Pension Scheme Trustees Ltd | London | 1997 |
| Arnold Advice Limited | Hatfield | 2021 |
| Arnold Capital Limited | Hereford | 2014 |
| Arnold Clark Insurance Services Limited | Glasgow | 1999 |
| Arnold Commercial Finance Limited | Taunton | 1990 |
| Arnold Company Holdings Ltd | Barnsley | 2016 |
| Arnold Construction Holdings Limited | Barnsley | 2024 |
| Arnold Farms Holdings Limited | Ombersley | 2021 |
| Arnold Financial Limited | Bournemouth | 2015 |
| Arnold Financial Services Ltd | Stoke-On-Trent | 2023 |
| Arnold Gorse Insurance Services Ltd | Southport | 2004 |
| Arnold Grant & Waters Limited | Chelmsford | 2016 |
| Arnold Read Financial Associates Limited | Lowestoft | 2010 |
| Arnold Richer, Curran Limited | Cardiff | 1974 |
| Arnold Stansby & Co. Limited | Manchester | 2011 |
| Arnold Stansby Holdings Limited | Manchester | 2012 |
| Arnold's Enterprises Limited | Bury St. Edmunds | 2020 |