| Architectural Developments & Planning Limited | Hospitality | 1992 |
| Archway Facilities Ltd | Administrative & support | 2013 |
| Arctic Technology Ventures Ltd | Information & communication | 2025 |
| Arda 23 Ltd | Hospitality | 2025 |
| Ardahan Ltd | Hospitality | 2023 |
| Area 2021 Ltd | Other services | 2023 |
| Area Planning Limited | Professional & scientific | 2015 |
| Arenamore Ltd | Professional & scientific | 2015 |
| Arete SWT Ltd | Information & communication | 2018 |
| Argenta Asset Management Limited | Real estate | 2018 |
| Argenta Build Limited | Real estate | 2011 |
| Argenta Developments Ltd | Construction | 2013 |
| Argenta Estates Limited | Real estate | 2010 |
| Argos Fire Protection Limited | Wholesale & retail | 2010 |
| Argus Shadow Ltd | Administrative & support | 2011 |
| Argyll Environmental Ltd | Professional & scientific | 2002 |
| Arhdee Limited | Transport & logistics | 2019 |
| ARI Dota Limited | Arts & recreation | 2023 |
| ARI Motorsport Ltd | Professional & scientific | 2005 |
| ARI Properties Ltd | Professional & scientific | 2004 |
| Ari's Healthy Life Ltd | Wholesale & retail | 2011 |
| Aribeonaty Holdings Limited | Financial services | 2023 |
| Arieh Ltd | Hospitality | 2026 |
| Arisaig Wealth Management Ltd | Extraterritorial | 2024 |
| ARK Assets Ltd | Construction | 2018 |
| ARK Construction (South West) Limited | Construction | 2014 |
| ARK Recruitment EST2023 Ltd | Administrative & support | 2023 |
| ARK Roofing and Guttering Services Limited | Construction | 2011 |
| ARK Roofing SW Ltd | Financial services | 2008 |
| ARK Vets Pinhoe Limited | Professional & scientific | 2014 |
| Arkcore Consulting Ltd | Information & communication | 2025 |
| Arkwright Technologies Limited | Information & communication | 2025 |
| ARL 001 Limited | Energy | 2017 |
| ARL 027 Limited | Energy | 2018 |
| Arlington & Barrington (Trewolek) Management Company Limited | Households | 2021 |
| Arlo Construction Limited | Construction | 2019 |
| Armada Investments Limited | Financial services | 1973 |
| Armada Street Residents Association Limited | Hospitality | 1994 |
| Armor (UK) Limited | Wholesale & retail | 1990 |
| Armor Print Solutions Ltd | Wholesale & retail | 2020 |
| Armour Sealed Units (Bristol) Limited | Construction | 1983 |
| Armstrong Bricklaying & Building Ltd | Construction | 2024 |
| Arno Property Developments Ltd | Construction | 2026 |
| Arnolds Kitchens Limited | Construction | 2013 |
| Aroha House Limited | Health & social care | 2007 |
| ARP Architects Ltd | Professional & scientific | 2022 |
| ARP42 Ltd | Financial services | 2016 |
| Arqa Advisory Ltd | Professional & scientific | 2025 |
| Array Associates Ltd | Professional & scientific | 2015 |
| Arrp Trading Limited | Wholesale & retail | 2021 |
| Art Work Exeter CIC | Administrative & support | 2016 |
| Artemis Environmental Solutions Limited | Water & waste | 2009 |
| Artemis Group (Devon) Ltd | Hospitality | 2024 |
| Article 36 | Professional & scientific | 2011 |
| Articsoft Technologies Limited | Information & communication | 2005 |
| Artigiano Espresso Bars Limited | Hospitality | 2012 |
| Artigiano ST Paul's Limited | Hospitality | 2015 |
| Artillery Court NO 1 Management Limited | Households | 2003 |
| Artillery Court NO 2 Management Limited | Households | 2003 |
| Artist Relations Ltd | Transport & logistics | 2017 |
| Artition Limited | Real estate | 2019 |
| Artium Collective Rental Ltd | Other services | 2017 |
| Artkof Enterprise Limited | Hospitality | 2021 |
| Artkof Plymouth Ltd | Hospitality | 2024 |
| Artogen Ltd | Financial services | 2025 |
| Artoli Limited | Real estate | 2025 |
| Artori Limited | Financial services | 2006 |
| Arwenack Hotel Limited | Real estate | 2018 |
| ARX and Arbor Ltd | Real estate | 2021 |
| AS Financial Management Limited | Financial services | 2023 |
| Asap Carpentry & Kitchens Limited | Manufacturing | 2009 |
| Asap Locksmiths Services Ltd | Administrative & support | 2020 |
| Asare Global Holdings Ltd | Real estate | 2026 |
| Asbestos Solutions Southwest Limited | Water & waste | 2018 |
| Ascendable Ltd | Information & communication | 2018 |
| Ascendria Limited | Financial services | 2024 |
| Ascent Printed Media Limited | Professional & scientific | 2023 |
| Ascentive AI Ltd | Information & communication | 2025 |
| Ascot Jewellers Limited | Wholesale & retail | 2012 |
| ASD Spiers Ltd | Health & social care | 2019 |
| ASG Information Services Ltd | Professional & scientific | 2025 |
| ASH Marine LLP | | 2012 |
| Ashborne Construction Solutions Limited | Construction | 2014 |
| Ashborne Properties Limited | Construction | 2015 |
| Ashbury First Limited | Administrative & support | 2026 |
| Ashford 2023 Ltd | Hospitality | 2023 |
| Ashford Plastering Southwest Limited | Construction | 2017 |
| Ashfords LLP | | 2009 |
| Ashfords Trust Corporation Limited | Administrative & support | 2022 |
| Ashgrove (ST Thomas) Management Company Limited | Households | 2006 |
| Ashleigh (Topsham) Management Limited | Households | 1977 |
| Ashleigh Health Ltd | Wholesale & retail | 2025 |
| Ashleigh Homes (UK) Ltd | Real estate | 2020 |
| Ashley House Printing Company Limited | Manufacturing | 2005 |
| Ashmoor House Weddings Ltd | Other services | 2026 |
| Ashram House Publishing Ltd | Information & communication | 2018 |
| Ashridge Property Ventures Limited | Real estate | 2019 |
| Ashton Cleaning Services (SW) Ltd | Administrative & support | 2012 |
| Ashtons Complete Limited | Real estate | 2013 |
| Ashwater Barton Management Company Limited | Extraterritorial | 1999 |