| Aristos Street Food Ltd | Hospitality | 2025 |
| Arixan Investments Limited | Real estate | 2021 |
| ARJ Northwest Ltd | Water & waste | 2025 |
| ARK Immersive Ltd | Information & communication | 2022 |
| ARK Investments Northwest Ltd | Real estate | 2022 |
| ARK Retail Group Ltd | Wholesale & retail | 2025 |
| ARK Support Services Ltd | Health & social care | 2024 |
| Arke Investment Ltd | Real estate | 2022 |
| Arkell Accountancy & Tax Ltd | Professional & scientific | 2019 |
| Arkham Estates Ltd | Real estate | 2018 |
| Arkham M&E Ltd | Construction | 2022 |
| Arkham Solar Maintenance Ltd | Construction | 2025 |
| Arkheion Architects Limited | Professional & scientific | 1999 |
| Arkk Investments Limited | Real estate | 2020 |
| Arkle Chase Limited | Households | 2020 |
| Arkm Investment Limited | Real estate | 2021 |
| Arkoss Limited | Construction | 2015 |
| Arks Stays Ltd | Real estate | 2024 |
| Arktemis Limited | Wholesale & retail | 2024 |
| Arkwood Projects Ltd | Extraterritorial | 2010 |
| Arlington Property Company Limited | Extraterritorial | 1982 |
| Arliza Projects Limited | Construction | 2017 |
| Arlo (NW) Limited | Professional & scientific | 2020 |
| Arlo Estates Ltd | Real estate | 2025 |
| ARM Beauty Ltd | Other services | 2022 |
| ARM Boxing Limited | Arts & recreation | 2012 |
| ARM Solar Holdings LLP | | 2023 |
| Armada 2002 Ltd | Construction | 2007 |
| Armada Model Designs Limited | Professional & scientific | 2006 |
| Armada Technologies Limited | Professional & scientific | 2020 |
| Armann Trading Ltd | Wholesale & retail | 2021 |
| Armar Holdings Ltd | Information & communication | 2022 |
| Armenian Import Limited | Wholesale & retail | 2024 |
| Armenian Taverna Limited | Hospitality | 2013 |
| Armeus Ltd | Financial services | 2025 |
| Armitage Global Solutions Limited | Transport & logistics | 2024 |
| Armitage Legacy Group Ltd | Financial services | 2026 |
| Armitage Property Maintenance Ltd | Administrative & support | 2020 |
| Armonia Wellness Ltd | Extraterritorial | 2022 |
| Armor M&E Ltd | Construction | 2026 |
| Armor Products International Limited | Professional & scientific | 1937 |
| Armour Industries Ltd | Manufacturing | 2023 |
| Arms Group Ltd | Wholesale & retail | 2016 |
| Arms Homes Ltd | Construction | 2019 |
| Armstrong Care and Support Services Ltd | Health & social care | 2023 |
| Armstrong Events NW Ltd | Arts & recreation | 2023 |
| Armstrong Motorcycles Limited | Manufacturing | 2009 |
| Armstrong Neurodevelopmental Consultancy Ltd | Health & social care | 2026 |
| Armstrong Rigging Ltd | Information & communication | 2021 |
| ARMSTRONG28 Ltd | Arts & recreation | 2025 |
| Armstrongs Solicitors Limited | Extraterritorial | 2006 |
| Arnaa Food Ltd | Hospitality | 2019 |
| Arnfield T&A Cafe Limited | Hospitality | 2023 |
| Arnhem Estates Ltd | Households | 2023 |
| Arnian Civil Engineering Limited | Construction | 2017 |
| Arniancourt Services Management Co Ltd | Real estate | 2020 |
| Arno Consultancy Ltd | Health & social care | 2021 |
| Arno Plumbing & Heating Limited | Construction | 2001 |
| Arnold & Arnold Holdings Limited | Financial services | 2024 |
| Arnold Kirkland Properties Ltd | Real estate | 2023 |
| Arnold Page Ltd | Real estate | 2017 |
| Arnold Prime Deals Ltd | Real estate | 2025 |
| Arnold Sanderson Limited | Transport & logistics | 2016 |
| Arnold's Aesthetics Ltd | Other services | 2021 |
| Arnold's Interiors Ltd. | Wholesale & retail | 2003 |
| Arnwell Joinery Ltd | Construction | 2019 |
| Aroa Educational Psychology Services Limited | Education | 2022 |
| Aroa Specialist Therapeutic Education Team Ltd | Education | 2025 |
| Aroha Anglesey Limited | Hospitality | 2024 |
| Arom Properties Limited | Real estate | 2025 |
| Aroma Art of Ceylon Ltd | Wholesale & retail | 2026 |
| Aroma Luxe Ltd | Wholesale & retail | 2025 |
| Aromaticauk Ltd | Wholesale & retail | 2024 |
| Aromedan Property Solutions Ltd | Real estate | 2026 |
| Aron's Place Ltd | Hospitality | 2024 |
| Arong Catering Ltd | Hospitality | 2024 |
| Arong Dining Ltd | Hospitality | 2019 |
| ARP Building Consultancy Limited | Professional & scientific | 2009 |
| ARP Engineering Services Ltd | Construction | 2013 |
| Arpg Construction Ltd | Construction | 2018 |
| Arpg Eco Ltd | Construction | 2020 |
| Arpg Investments Ltd | Financial services | 2018 |
| ARR Homes Ltd | Information & communication | 2017 |
| Arr-Lec Ltd | Construction | 2024 |
| Arris Insulated Renders (NW) Ltd | Wholesale & retail | 2008 |
| Arrivesafe Ltd | Information & communication | 2025 |
| Arrow Business Comms (UK) Limited | Financial services | 2019 |
| Arrow Business Communications Limited | Information & communication | 2005 |
| Arrow Business Communications PS Limited | Professional & scientific | 2021 |
| Arrow Business Communications Trustee Limited | Administrative & support | 2017 |
| Arrow Business Telecoms Limited | Financial services | 2019 |
| Arrow Communications Group Limited | Financial services | 2019 |
| Arrow Communications Holdings Limited | Financial services | 2019 |
| Arrow Energy Services Limited | Administrative & support | 2026 |
| Arrow Gift Co Ltd | Other services | 2021 |
| Arrow Green Technologies (UK) Limited | Professional & scientific | 2004 |
| ARROW14 Ltd | Real estate | 2026 |
| Arrowe Park Laundrette (NW) Limited | Administrative & support | 2022 |
| Arrowe Security Ltd | Administrative & support | 2025 |
| Arrows Electrical Ltd | Construction | 2018 |