| Ardana Ltd | Professional & scientific | 2025 |
| Ardaros Future Trading Limited | Professional & scientific | 2018 |
| Arden House Property Ltd | Construction | 2025 |
| Ardent Joie Support Limited | Health & social care | 2024 |
| Ardent Staffing Ltd | Administrative & support | 2022 |
| Ardenza Consultants Limited | Professional & scientific | 2025 |
| Ardoa UK Limited | Wholesale & retail | 2019 |
| Ardoc Ltd | Real estate | 2022 |
| Ards Aero Limited | Transport & logistics | 2017 |
| Ardsley House Hotel Limited | Hospitality | 1995 |
| Ardua Limited | Financial services | 1998 |
| Ardwick Developments Limited | Extraterritorial | 2016 |
| ARE01 Limited | Professional & scientific | 2023 |
| ARE02 Limited | Professional & scientific | 2023 |
| Area 164 Community Interest Company | Health & social care | 2017 |
| Areer Ltd | Wholesale & retail | 2022 |
| Aren Medical Limited | Health & social care | 2018 |
| Arena 24SEVEN Limited | Wholesale & retail | 2017 |
| Arena Air Conditioning Limited | Professional & scientific | 2014 |
| Arena Art and Design Association | Arts & recreation | 1996 |
| Arena Cleaning Services Limited | Administrative & support | 1990 |
| Arena Padel NW Limited | Other services | 2025 |
| Arendje Consultancy Ltd | Professional & scientific | 2015 |
| Arends Consultancy Limited | Health & social care | 2015 |
| Areosky Aviation Ltd. | Transport & logistics | 2011 |
| Arepas Limited | Hospitality | 2013 |
| Ares Actuators Limited | Wholesale & retail | 2022 |
| Ares Valves Limited | Wholesale & retail | 2022 |
| Aret - W.O.V Ltd | Professional & scientific | 2025 |
| Arete Active Ltd | Arts & recreation | 2024 |
| Arete Asset Management Limited | Administrative & support | 2020 |
| Arete Capital Partners LLP | | 2020 |
| Arete Capital Partners UK Limited | Administrative & support | 2020 |
| Arete Connect Limited | Professional & scientific | 2021 |
| Arete Group Limited | Professional & scientific | 2023 |
| Arete Holdings Limited | Financial services | 2020 |
| Arete Insight Limited | Professional & scientific | 2021 |
| Arete Investors 1 (Nominees) Limited | Professional & scientific | 2020 |
| Arete Investors 10 (Nominees) Limited | Professional & scientific | 2021 |
| Arete Investors 11 (Nominees) Limited | Professional & scientific | 2021 |
| Arete Investors 12 (Nominees) Limited | Professional & scientific | 2021 |
| Arete Investors 14 (Nominees) Limited | Professional & scientific | 2021 |
| Arete Investors 15 (Nominees) Limited | Professional & scientific | 2021 |
| Arete Investors 16 (Nominees) Limited | Professional & scientific | 2021 |
| Arete Investors 17 (Nominees) Limited | Professional & scientific | 2021 |
| Arete Investors 18 (Nominees) Limited | Professional & scientific | 2021 |
| Arete Investors 19 (Nominees) Limited | Professional & scientific | 2022 |
| Arete Investors 2 (Nominees) Limited | Professional & scientific | 2020 |
| Arete Investors 20 (Nominees) Limited | Professional & scientific | 2022 |
| Arete Investors 21 (Nominees) Limited | Professional & scientific | 2021 |
| Arete Investors 22 (Nominees) Limited | Financial services | 2021 |
| Arete Investors 23 (Nominees) Limited | Professional & scientific | 2024 |
| Arete Investors 3 (Nominees) Limited | Professional & scientific | 2020 |
| Arete Investors 4 (Nominees) Limited | Professional & scientific | 2020 |
| Arete Investors 5 (Nominees) Limited | Professional & scientific | 2021 |
| Arete Investors 6 (Nominees) Limited | Professional & scientific | 2021 |
| Arete Investors 7 (Nominees) Limited | Professional & scientific | 2021 |
| Arete Investors 8 (Nominees) Limited | Professional & scientific | 2021 |
| Arete Investors 9 (Nominees) Limited | Professional & scientific | 2021 |
| Arete Limited | Professional & scientific | 2021 |
| Arete Partners Limited | Professional & scientific | 2023 |
| Arete Risk Services 1 (Nominees) Limited | Professional & scientific | 2020 |
| Arete Risk Services 2 (Nominees) Limited | Professional & scientific | 2020 |
| Arete Risk Services 3 (Nominees) Limited | Professional & scientific | 2020 |
| Arete Risk Services 4 (Nominees) Limited | Professional & scientific | 2021 |
| Arete Trading Limited | Professional & scientific | 2021 |
| Arete Trading Nominees Limited | Professional & scientific | 2020 |
| Arete Wealth Management Limited | Administrative & support | 2020 |
| Aretevita Care Group Ltd | Health & social care | 2026 |
| Arewa UK Ltd | Real estate | 2001 |
| Arexen Ltd | Wholesale & retail | 2025 |
| Argentino Construction Services Limited | Construction | 2016 |
| Argon Heating & Plumbing Ltd | Construction | 2022 |
| Argon Heating Solutions Limited | Construction | 2018 |
| Argonaut Capital Trading Ltd | Administrative & support | 2018 |
| Argontekton Limited | Construction | 2021 |
| Argyle Construction Limited | Construction | 2018 |
| Argyle Management Services | | 1999 |
| Argyle Property Group Limited | Real estate | 2021 |
| Argyle Sports & Work Wear Limited | Wholesale & retail | 2006 |
| ARH Lighting Ltd | Construction | 2019 |
| ARI Smart Hair CUT Ltd | Other services | 2024 |
| Aria Cove Ltd | Wholesale & retail | 2018 |
| Aria's Flowers Ltd | Wholesale & retail | 2024 |
| Ariadne HR Services Ltd | Professional & scientific | 2005 |
| Ariana Tailoring Limited | Wholesale & retail | 2024 |
| ARIANA7242 R&D Ltd | Professional & scientific | 2019 |
| Aridin Investments Ltd | Real estate | 2020 |
| Ariel 1929 Limited | Hospitality | 2023 |
| Ariel Trust Limited | Education | 1987 |
| Aries Motors Ltd | Wholesale & retail | 2021 |
| Aries Property Group Limited | Real estate | 2017 |
| Arif & Sons Property Investments Limited | Real estate | 2024 |
| Ariko Global Ltd | Health & social care | 2023 |
| Arillis Services Ltd | Administrative & support | 2026 |
| Arinview Limited | Real estate | 1994 |
| Ariosha Ltd | Professional & scientific | 2025 |
| Arise Teen and Adult Support Services Ltd | Hospitality | 2022 |
| Aristocat Cleaning Limited | Other services | 2014 |
| Ariston Consultancy Ltd | Manufacturing | 2026 |