| Agillia Group Limited | Construction | 2022 |
| AGP Somerset Limited | Construction | 2010 |
| Agrogaz Ltd | Construction | 2025 |
| AGT Inheritance Tax & Estate Planning Limited | Professional & scientific | 2013 |
| Ahomzz Ltd | Real estate | 2016 |
| Aico Solutions Limited | Information & communication | 2024 |
| Aievah Ltd | Information & communication | 2025 |
| Aikya Systems Limited | Information & communication | 2010 |
| AIP Welding Supplies Limited | Wholesale & retail | 2015 |
| Air Conditioning Group Limited | Wholesale & retail | 2011 |
| Air South West 2000 Limited | Administrative & support | 2002 |
| Aircraft Access Limited | Manufacturing | 1989 |
| Aircraft Ground Equipment Supply Limited | Manufacturing | 1987 |
| Aircraft Ground Leasing Solutions Limited | Transport & logistics | 2017 |
| AJ Accommodation Ltd | Hospitality | 2017 |
| AJB (South West) Limited | Construction | 2002 |
| AJG Lettings Ltd | Real estate | 2020 |
| AJH Contractors Ltd | Construction | 2011 |
| AJH Decking Limited | Construction | 2018 |
| AJH Media & Marketing Ltd | Professional & scientific | 2024 |
| AJM Building Services Ltd | Construction | 2026 |
| AJW Property Holdings Limited | Real estate | 2022 |
| AK. Kebab and Pizza Ltd | Hospitality | 2025 |
| Akaya Gaia Ltd | Hospitality | 2025 |
| Akhter Brothers Limited | Real estate | 2022 |
| Alak Spa Ltd | Other services | 2023 |
| Alamy Homes Limited | Real estate | 2024 |
| Alan Ludewig Consulting Ltd | Professional & scientific | 2020 |
| ALB Civils & Groundworks Ltd | Construction | 2024 |
| Aldrino Screens Limited | Wholesale & retail | 2025 |
| Alex Thai Kitchen Ltd | Hospitality | 2024 |
| ALEXVAS80 Limited | Arts & recreation | 2020 |
| Aley Property Developments Ltd | Construction | 2020 |
| Alfa Resins Ltd | Construction | 2024 |
| Alfoxton Enterprises Ltd | Education | 2023 |
| Algoran Limited | Real estate | 1982 |
| Alkamorph Commercial Services Ltd | Manufacturing | 2025 |
| ALL at Sea Therapy Limited | Health & social care | 2022 |
| ALL Fuels Limited | Wholesale & retail | 2020 |
| ALL Tails Essential Pet Services Limited | Extraterritorial | 2024 |
| ALL Transport Recovery Ltd | Wholesale & retail | 2022 |
| Allen's Construction & Carpentry Limited | Construction | 2023 |
| Allens Carpentry Limited | Construction | 2023 |
| Allerton Associates Ltd | Professional & scientific | 2011 |
| Alletsons Limited | Professional & scientific | 2008 |
| Allied Aerosols Limited | Wholesale & retail | 2017 |
| Alpha Classic Motorcycles Limited | Wholesale & retail | 2010 |
| Altered Move Ltd | Information & communication | 2021 |
| Alternative Energy Ukraine Ltd | Professional & scientific | 2017 |
| AM & JPT Allan Limited | Real estate | 2021 |
| AMA Switchgear Ltd | Manufacturing | 2022 |
| Amalia Bhalli Academy Ltd | Education | 2022 |
| Amalyn Build & Glaze Ltd | Construction | 2025 |
| Ambro-Sol UK Limited | Wholesale & retail | 2025 |
| AMC Civils Ltd | Construction | 2015 |
| Amelarch Limited | Professional & scientific | 2014 |
| Amicus Law (South West) LLP | | 2015 |
| Amiys Limited | Information & communication | 2012 |
| AMJ Consulting (Bridgwater) Limited | Professional & scientific | 2023 |
| Amri Systems Ltd | Information & communication | 2020 |
| AMS Nuclear Engineering (Holdings) Limited | Financial services | 2022 |
| AMS Nuclear Engineering Ltd | Professional & scientific | 1999 |
| Andee Knits Ltd | Wholesale & retail | 2010 |
| Andrea Mattia Alfresco Limited | Hospitality | 1990 |
| Andrew and Levis Investments Limited | Professional & scientific | 2025 |
| Andrew C. Smallwood & Co. Limited | Professional & scientific | 2001 |
| Andrew Lees Lettings Limited | Real estate | 2014 |
| Andy Clifford TV Limited | Information & communication | 2008 |
| Andy’S MAN With a Van Ltd | Transport & logistics | 2024 |
| Angel Crescent Management Limited | Real estate | 1987 |
| Ania Haie Limited | Wholesale & retail | 2018 |
| Anom Consulting Limited | Professional & scientific | 2023 |
| Ansell Services Limited | Administrative & support | 2023 |
| Antler Construct Limited | Construction | 2018 |
| Anubis Contracting & Engineering Ltd | Professional & scientific | 2020 |
| Anvil Equine Limited | Professional & scientific | 2010 |
| AP Heating and Plumbing Ltd | Construction | 2023 |
| AP2 (2011) Ltd | Professional & scientific | 2011 |
| Apac Holdings and Systems Ltd | Wholesale & retail | 2011 |
| Apex Developments & Construction Ltd | Construction | 2026 |
| Apex Soccer Group Limited | Professional & scientific | 2017 |
| Apna Peri Peri Ltd | Hospitality | 2025 |
| Apple Technical Solutions Limited | Energy | 2003 |
| Apple Tree Hotel Limited | Hospitality | 2006 |
| Applied Bacterial Control Limited | Professional & scientific | 2016 |
| Appmilla Ltd | Information & communication | 2020 |
| APS Scaffolding Ltd | Construction | 2015 |
| Aquapoolco Limited | Construction | 2010 |
| Aquilan Limited | Information & communication | 2015 |
| Aquilan Properties Limited | Administrative & support | 2018 |
| Arbor Services Limited | Agriculture & fishing | 2016 |
| ARC Commercial Properties Limited | Real estate | 2026 |
| ARC Property Development Ltd | Construction | 2021 |
| Arcadia Activities Limited | Arts & recreation | 2018 |
| Archi-Vista Limited | Professional & scientific | 2017 |
| Architectural Trade UK Ltd | Construction | 2018 |
| Architecture by Studio Hive Limited | Professional & scientific | 2020 |
| Ardas Recruitment Ltd | Administrative & support | 2021 |
| Ardmore Ridge Ltd | Financial services | 2025 |
| Ardosia Ltd | Hospitality | 2024 |