| Arcadia Trust Group Limited | Langport | 2019 |
| Arcadian Corporation Limited | Leigh-On-Sea | 2003 |
| Arcadian Group Limited | Peterborough | 2016 |
| Arcadian International Ltd | London | 2025 |
| Arcadian Risk Capital (UK) Ltd | London | 2020 |
| Arcadis (BAC) Limited | London | 2011 |
| Arcadis GEN Holdings Limited | London | 2019 |
| Arcadis Group Limited | London | 1994 |
| Arcadis International Holdings Limited | London | 1993 |
| Arcaid Group Ltd | Manchester | 2026 |
| Arcalaudis Limited | Kent | 2005 |
| Arcam-B Limited | Newport | 2025 |
| Arcana Financial Consulting Limited | Sale | 2016 |
| Arcana Holdings Limited | Blandford Forum | 2025 |
| Arcane Advocate Ltd | Henley-In-Arden | 2020 |
| Arcane Investments Limited | Milton Keynes | 2017 |
| Arcane Protection Ltd | Northampton | 2018 |
| Arcane UK Ltd | Lytham St Annes | 2019 |
| Arcano Holding Ltd | London | 2024 |
| Arcantel Limited | Bollington | 2019 |
| Arcanum Asset Management Limited | Bristol | 2010 |
| Arcanum Holding Ltd | Thatcham | 2023 |
| Arcap Funding Ltd | Borehamwood | 2017 |
| Arcap Partners Ltd | Borehamwood | 2015 |
| Arcara Group Limited | Norwich | 2026 |
| Arcare Boscobel House Limited | Wolverhampton | 2017 |
| Arcare Camber Holdings Limited | Wolverhampton | 2019 |
| Arcare Codsall Holdings Limited | Wolverhampton | 2024 |
| Arcare Orton Holdings Limited | Wolverhampton | 2023 |
| Arcaria Financial Solutions Ltd | Colchester | 2012 |
| Arcata Holdings Limited | Edinburgh | 2021 |
| Arcbridge International Ltd | Worthing | 2026 |
| Arcea Holdings Limited | King'S Lynn | 2025 |
| Arceio Limited | Milton Keynes | 2024 |
| Arcelle Holdings Ltd | Leicester | 2022 |
| Arcesium UK Private Limited | London | 2020 |
| Arcetron Systems Ltd | London | 2025 |
| Arcgroup SPV 1 Ltd | Ashington | 2025 |
| Arch Biocides Trustee Limited | Manchester | 2004 |
| Arch Brokerage Ltd | Northwich | 2025 |
| Arch Chemicals Products Limited | Manchester | 1970 |
| Arch Chemicals UK Finance | Manchester | 2004 |
| Arch Consultants Avis Limited | Caterham | 2021 |
| Arch Consultants Hardy Limited | Caterham | 2021 |
| Arch Corporate Member (NO.10) Limited | London | 2015 |
| Arch Corporate Member (NO.11) Limited | London | 2015 |
| Arch Corporate Member (NO.12) Limited | London | 2015 |
| Arch Corporate Member (NO.14) Limited | London | 2017 |
| Arch Corporate Member (NO.16) Limited | London | 2017 |
| Arch Corporate Member (NO.17) Limited | London | 2020 |
| Arch Corporate Member (NO.18) Limited | London | 2020 |
| Arch Corporate Member (NO.19) Limited | London | 2024 |
| Arch Corporate Member (NO.3) Limited | London | 2013 |
| Arch Corporate Member (NO.4) Limited | London | 2013 |
| Arch Corporate Member (NO.6) Limited | London | 2014 |
| Arch Corporate Member (NO.7) Limited | London | 2014 |
| Arch Corporate Member Limited | London | 2007 |
| Arch Estate Holdings Limited | Market Drayton | 2018 |
| Arch Europe Insurance Services Ltd | London | 2008 |
| Arch Financial Holdings (UK) Limited | London | 2007 |
| Arch Financial Services Ltd | Chessington | 2021 |
| Arch Group Holdings Ltd | London | 2026 |
| Arch Group UK Holdings Ltd | Borehamwood | 2023 |
| Arch Holdco Ltd | Manchester | 2024 |
| Arch Holdings (SW) Ltd | Porth | 2019 |
| Arch Insurance (UK) Limited | London | 2003 |
| Arch Intermediaries Group Limited | London | 2018 |
| Arch Konsult Ltd | Ashford | 2017 |
| Arch Managing Agency Limited | London | 2009 |
| Arch Partners Ltd | London | 2021 |
| Arch Pier Capital Limited | London | 2019 |
| Arch Pier Industries Limited | London | 2019 |
| Arch Private Equity Ltd | Widnes | 2013 |
| Arch South Group Ltd | Southampton | 2023 |
| Arch Syndicate Investments Ltd | London | 2008 |
| ARCH2 Limited | Maidstone | 2023 |
| Archaleon Capital Limited | London | 2026 |
| Archangel Broker Ltd | Broughton | 2019 |
| Archangel Capital Management Limited | London | 2021 |
| Archangel Consultancy Ltd | Iver | 2023 |
| Archangel Estates Limited | Weybridge | 2014 |
| Archangel Investors (Management) Limited | Edinburgh | 2014 |
| Archangel Michael Holding Limited | Southend-On-Sea | 2021 |
| Archangel Private Finance Limited | London | 2026 |
| Archangel Property Specialists Limited | Sheffield | 2024 |
| Archax Brokerage Ltd | London | 2018 |
| Archax Capital Ltd | London | 2018 |
| Archax Carbon Nominees Ltd | London | 2022 |
| Archax Custody Ltd | London | 2018 |
| Archax Digital Nominees Limited | London | 2022 |
| Archax Ltd | London | 2018 |
| Archax Markets Ltd | London | 2019 |
| Archax Nominees Ltd | London | 2020 |
| Archax Ventures Ltd | London | 2018 |
| Archbert Limited | Leigh On Sea | 2017 |
| Archbourne Limited | London | 2005 |
| Archbrook Medical Ltd | Manchester | 2026 |
| Archbury Ltd | Ascot | 2021 |
| Archcrest Capital Advisory Ltd | London | 2024 |
| Arche Innovations Limited | Penarth | 2012 |