| Aristotle Partnerships Limited | Sheffield | 2019 |
| Aristotle Topco Limited | London | 2023 |
| Aristx Capital Ltd | London | 2026 |
| Aritos Properties Limited | London | 2014 |
| Aritrad Limited | Wembley | 2025 |
| Ariv Services Limited | London | 2024 |
| Arivant Holdings Limited | London | 2024 |
| Ariya Khella Holdings Ltd | Farnham Common | 2021 |
| Ariyan Holdings Limited | Leicestser | 2017 |
| Ariyoni Ltd | London | 2022 |
| Arizia Ventures Limited | London | 2025 |
| Arizona Bidco Limited | London | 2026 |
| Arizona Midco Limited | London | 2026 |
| Arizona Topco Limited | London | 2026 |
| ARJ Capital Investments Limited | Watford | 2020 |
| ARJ Capital Limited | Watford | 2016 |
| ARJ Construction Holdings Limited | St. Albans | 2013 |
| ARJ Financial Services Ltd | Barnsley | 2015 |
| ARJ QA Limited | Cardiff | 2013 |
| ARJ QCA Limited | Cardiff | 2022 |
| Arjan Capital Ltd | London | 2013 |
| Arjant Limited | London | 2006 |
| Arjen Jonker Ltd | St Austell | 2025 |
| Arjo Holdings Ltd | Belfast | 2026 |
| Arjo Pension Trustee Limited | Dunstable | 2016 |
| Arjobex Holding UK Limited | Clacton-On-Sea | 2020 |
| Arjon Holdings Limited | Market Drayton | 2021 |
| Arjowiggins Group Limited | Glasgow | 2019 |
| Arjowiggins Papers Limited | Edinburgh | 2019 |
| Arjs Contracting Ltd | Leicester | 2015 |
| Arjun GP | Edinburgh | 2018 |
| Arjun Infrastructure Partners II Limited | Reading | 2015 |
| Arjun Infrastructure Partners III Limited | Reading | 2017 |
| Arjun Infrastructure Partners Limited | Reading | 2015 |
| Arjun Infrastructure Partners Midco Limited | Reading | 2018 |
| ARK Ange Financial Strategy Ltd | London | 2015 |
| ARK Angel Capital Ltd | London | 2018 |
| ARK Atvs Holding Ltd | Minehead | 2024 |
| ARK Business Finance Ltd | Leicester | 2017 |
| ARK Business Holdings Limited | Fareham | 2026 |
| ARK Capital Investments Limited | Derby | 2017 |
| ARK Commercial Finance Ltd | Newport | 2022 |
| ARK Contour Holdings Limited | Harlow | 2015 |
| ARK Core Ltd | Mildenhall | 2025 |
| ARK Corporate Member (NO.2) Limited | London | 2007 |
| ARK Corporate Member (NO.3) Limited | London | 2008 |
| ARK Corporate Member (NO.4) Limited | London | 2013 |
| ARK Corporate Member Limited | London | 2007 |
| ARK Developments Group Ltd | London | 2023 |
| ARK Electric Holding Ltd | Derry | 2026 |
| ARK Enterprises Holding Limited | Epsom | 2026 |
| ARK Family Care Ltd | London | 2025 |
| ARK Family Group Ltd | Swadlincote | 2026 |
| ARK Financial Consultants Limited | Leicester | 2025 |
| ARK Financial Holding Group Ltd | West Midlands, England | 2023 |
| ARK Financial Planning Limited | Oldham | 2003 |
| ARK Fiscal Solutions Limited | Nottingham | 2010 |
| ARK FX Limited | London | 2026 |
| ARK Global Investment Consulting Ltd | London | 2025 |
| ARK Group Holdings Limited | Poole | 2024 |
| ARK Group Scotland Limited | Edinburgh | 2025 |
| ARK Hoey Properties Ltd | Halifax | 2016 |
| ARK Holding Corporation Ltd | Camberley | 2025 |
| ARK Holdings (London) Limited | Northwood Hills | 2015 |
| ARK Holdings (Spalding) Limited | Spalding | 2014 |
| ARK Independent Solutions Limited | Croydon | 2019 |
| ARK Insolvency Ltd | Stockport | 2022 |
| ARK Insurance Group Limited | Coventry | 2014 |
| ARK Investment Advisers Ltd | Godalming | 2020 |
| ARK Investment Holdings Limited | London | 2024 |
| ARK Investment Management Ltd | London | 2014 |
| ARK Investments Group Limited | London | 2016 |
| ARK Mortgages Ltd | Ilford | 2020 |
| ARK Newco Limited | Hemel Hempstead | 2025 |
| ARK One Holdings Ltd | London | 2025 |
| ARK Partners Ltd | London | 2025 |
| ARK Property & Investments Ltd | Bideford | 2012 |
| ARK Roofing SW Ltd | Exeter | 2008 |
| ARK Service Holdings Ltd | Sheffield | 2023 |
| ARK Spiers Limited | Ashby-De-La-Zouch | 2025 |
| ARK Syndicate Management Limited | London | 2006 |
| ARK Traders Ltd | Gravesend | 2011 |
| ARK UK Bidco Limited | Nottingham | 2025 |
| ARK UK Midco Limited | Nottingham | 2025 |
| ARK UK Topco Limited | Nottingham | 2025 |
| ARK UN Limited | Truro | 2026 |
| ARK Venture Holdings Limited | North Heath | 2023 |
| ARK Venture Investments Limited | Pulborough | 2023 |
| Arka Holdings Ltd | Wolverhampton | 2022 |
| Arka International, Ltd | London | 2022 |
| Arkad Asset Management Ltd | Manchester | 2023 |
| Arkad Limited | Leicester | 1987 |
| Arkadiak Labs Ltd | London | 2024 |
| Arkadian Strategic Metals PLC | London | 2004 |
| Arkady Holdings Limited | Norwich | 2026 |
| Arkaig Ltd | Edinburgh | 2021 |
| Arkan Holdings Ltd | Birmingham | 2023 |
| Arkanum Management Limited | Heckmondwike | 2004 |
| Arkas Bidco Limited | London | 2025 |
| Arkas Midco 1 Limited | London | 2025 |