| Arkonik Limited | Wholesale & retail | 2007 |
| Arkonik.Com Limited | Extraterritorial | 2014 |
| ARM Building Supplies Limited | Wholesale & retail | 2025 |
| ARM in ARM Care Limited | Administrative & support | 2018 |
| Armada Athletics Network CIC | Other services | 2013 |
| Armada Cars Limited | Wholesale & retail | 2006 |
| Armada Civil Engineering (SW) Limited | Construction | 2015 |
| Armada Construction Limited | Construction | 2018 |
| Armada Court Limited | Real estate | 2019 |
| Armada Growth Ltd | Administrative & support | 2026 |
| Armada Kitchens, Bathrooms and Bedrooms Ltd | Wholesale & retail | 2022 |
| Armada Lettings (SW) Ltd | Real estate | 2018 |
| Armada Marine Limited | Administrative & support | 2004 |
| Armada Rolls Limited | Hospitality | 2026 |
| Armada Social Work Services Limited | Health & social care | 2016 |
| Armada Street Flats Limited | Real estate | 2014 |
| Armada Way House Ltd | Construction | 2026 |
| Armstrong Motor Company Ltd | Wholesale & retail | 2025 |
| Arnold Energy Transport Ltd | Transport & logistics | 2026 |
| Arrabon Trust | Health & social care | 2010 |
| Arribars Mexican Limited | Hospitality | 2026 |
| Arrisesca Ltd | Information & communication | 2022 |
| Arro Fitness and Holistic Wellness CIC | Health & social care | 2023 |
| ARS Management Ltd | Real estate | 2026 |
| Art @ Ltd. | Wholesale & retail | 2016 |
| Art and Energy CIC | Arts & recreation | 2019 |
| Art Appreciation Limited | Information & communication | 2020 |
| Art Craft & Laughter CIC | Health & social care | 2020 |
| Art SAN Holdings Ltd | Financial services | 2025 |
| Artemis BF60 Partnership | | 2021 |
| Artemis Optical (Holdings) Limited | Manufacturing | 2008 |
| Artemis Optical Limited | Manufacturing | 1952 |
| Artemis Training Ltd | Information & communication | 2016 |
| Arterne 2 Nurse Limited | Administrative & support | 2018 |
| Arterne Academy Limited | Education | 2026 |
| Arterne Care Limited | Health & social care | 2020 |
| Arterne: Enriching the Next Generation CIC | Administrative & support | 2016 |
| Artful Events and Media Limited | Information & communication | 2026 |
| Arthur Thomas Holdings Ltd | Financial services | 2024 |
| Arthur Thomas Trading Limited | Wholesale & retail | 2018 |
| Arthur, Arthur and Company Limited | Information & communication | 2025 |
| Artificial Lawns Eastriding Ltd | Administrative & support | 2018 |
| Artistic Framing Limited | | 1968 |
| Arundal Astronautics Ltd | Professional & scientific | 2016 |
| Arundel Court Management (Plymouth) Limited | Real estate | 2014 |
| ARW Heating Limited | Construction | 2018 |
| Aryaa Group Ltd | Wholesale & retail | 2025 |
| Aryan Rayan Ltd | Hospitality | 2014 |
| Aryanas Kitchen Ltd | Hospitality | 2023 |
| Aryans Holding Ltd | Hospitality | 2024 |
| AS Dental Limited | Health & social care | 2018 |
| AS Plumbing Heating Renewables Ltd | Construction | 2016 |
| AS Tax and Accounting Ltd | Professional & scientific | 2026 |
| ASA Barber Limited | Other services | 2025 |
| Asas Business Solutions Ltd | Professional & scientific | 2016 |
| ASC GAS Engineers Ltd | Construction | 2017 |
| ASC Plumbing & Heating Limited | Construction | 2017 |
| ASC Scaffolding Contractors (South) Ltd | Construction | 2018 |
| Ascough Management Services Limited | Financial services | 1978 |
| Aseptic Technology and Design Limited | Professional & scientific | 2001 |
| ASH & Williams Ltd | Administrative & support | 2003 |
| ASH Rice Holdings Ltd | Financial services | 2026 |
| Ashabullah Ltd | Wholesale & retail | 2024 |
| Ashbourne (Barbican) Management Limited | Households | 1986 |
| Ashburton Concepts Limited | Information & communication | 2017 |
| Ashcroft & Booth Limited | Real estate | 2005 |
| Ashford 3 Ltd | Real estate | 2025 |
| Ashford Renovations Ltd | Construction | 2015 |
| Ashford Road SW Ltd | Households | 2026 |
| Ashleigh Court Management Company Limited | Households | 1986 |
| Ashleigh Manor Residential Care Home Ltd | Hospitality | 2003 |
| Ashley Events Limited | Arts & recreation | 2010 |
| Ashley Marie Photography Ltd | Information & communication | 2016 |
| Ashley Purdy Roofing Ltd | Construction | 2026 |
| Ashmill & Stone Property Group Ltd | Real estate | 2026 |
| Ashti Supermarket Ltd | Wholesale & retail | 2025 |
| Ashton (PLY) Ltd | Real estate | 2018 |
| Ashwood Studios Limited | Administrative & support | 2002 |
| Asia GC Ltd | Wholesale & retail | 2019 |
| Asia Shaheen Security Services Company Limited | Administrative & support | 2026 |
| Asign Ltd | Professional & scientific | 2015 |
| Asjs Medical Systems Ltd | Information & communication | 2026 |
| Asjsmedical Ltd | Health & social care | 2019 |
| ASK Elliott Ltd | Financial services | 2020 |
| ASK WHY (Cornwall) Limited | Professional & scientific | 2022 |
| Asmk Commercial Investment Limited | Wholesale & retail | 2025 |
| Asom Ltd | Wholesale & retail | 2023 |
| Aspect Electrical & GAS Services Ltd | Manufacturing | 2005 |
| Aspect M&E Consultancy Limited | Professional & scientific | 2020 |
| Aspect Solar Maintenance Limited | Manufacturing | 2016 |
| Aspire Apparel Ltd | Wholesale & retail | 2025 |
| Aspire Student Living (2) Limited | Real estate | 2012 |
| Aspire Student Living (3) Limited | Construction | 2015 |
| Aspire Student Living 2 Management Ltd | Real estate | 2013 |
| Aspire Student Living 3 Management Ltd | Real estate | 2017 |
| ASPIRE2LIVE CIC | Education | 2016 |
| Asquith Group Holdings Limited | Financial services | 2017 |
| Asquith Group Limited | Manufacturing | 2017 |
| Asset Finance SW Ltd | Administrative & support | 2024 |
| Assistants at Hand (South West) Ltd | Health & social care | 2015 |