| Antique Rose Interiors Limited | Wholesale & retail | 2008 |
| Anton Shutters Ltd | Construction | 2026 |
| Antonietta Burton Ventures Limited | Real estate | 2025 |
| Antron Manor Care Home Ltd | Real estate | 2026 |
| Anviso Limited | Information & communication | 2014 |
| Anya Dramadoc Ltd | Information & communication | 2025 |
| Anything Human Ltd | Professional & scientific | 2024 |
| Anzen Systems Ltd | Information & communication | 2023 |
| Aoglowaesthetics Ltd | Other services | 2024 |
| AP Construction and Logistics Group Ltd | Construction | 2024 |
| AP Sensing UK Ltd | Professional & scientific | 2015 |
| Apacor Limited | Manufacturing | 1997 |
| Apartmentinthecity Limited | Real estate | 2005 |
| APC Johnson Consulting Limited | Professional & scientific | 2018 |
| Apex Accounting and Tax Limited | Professional & scientific | 2025 |
| Apex Electrical Services (Wokingham) Ltd | Construction | 2011 |
| Apex Investors Ltd | Construction | 2023 |
| Apex Prime Developments Ltd | Construction | 2023 |
| Apex Probes Ltd | Professional & scientific | 2018 |
| Apex Tech QA Solutions Ltd | Information & communication | 2026 |
| Apollo Vision Limited | Information & communication | 2024 |
| App Management Contracts Ltd | Information & communication | 2015 |
| Appcyc Limited | Information & communication | 2016 |
| Appia Infrastructure Solutions Limited | Professional & scientific | 2008 |
| Applewhaite Carpentry Limited | Construction | 2016 |
| Appromatt Ltd | Construction | 2011 |
| Appsofficial Ltd | Manufacturing | 2024 |
| Apres at Home Ltd | Manufacturing | 2020 |
| Apro Electronics Limited | Wholesale & retail | 2002 |
| APRONS4WORK Ltd | Wholesale & retail | 2024 |
| Aptimized Limited | Information & communication | 2017 |
| Aquaclean Solutions Limited | Administrative & support | 2024 |
| Aquarix Limited | Real estate | 2021 |
| Aquaticaddiction Limited | Wholesale & retail | 2018 |
| AR & RF Property Limited | Real estate | 2017 |
| Aragon Court Management Company Limited | Households | 1986 |
| Arbel Solutions Ltd | Information & communication | 2025 |
| Arben Precision Sheet Metal Limited | Manufacturing | 2007 |
| Arbor Lane Garage Limited | Wholesale & retail | 2010 |
| Arborfield Bouncy Castles Ltd | Administrative & support | 2010 |
| Arborfield Properties Ltd | Real estate | 2019 |
| ARC Control Systems Limited | Construction | 2001 |
| ARC Gym Ltd | Arts & recreation | 2018 |
| ARC Leisure Ltd | Arts & recreation | 2019 |
| ARC Plumbing & Heating Ltd | Construction | 2016 |
| Arcadia Design Limited | Professional & scientific | 2024 |
| Arch Consulting Services Limited | Information & communication | 2024 |
| Archdezine Limited | Professional & scientific | 2014 |
| Archetype Consulting Ltd | Information & communication | 2015 |
| Archie Consulting Services Limited | Information & communication | 2018 |
| Archie Hinton Hire Ltd | Administrative & support | 2016 |
| Archie Pango Ltd | Hospitality | 2018 |
| Archie's Purpose Ltd | Real estate | 2024 |
| Architectural Associates Ltd | Construction | 2012 |
| Architectural Brick & Stone Ltd | Wholesale & retail | 2010 |
| Architectural FX Ltd | Wholesale & retail | 2000 |
| Archtizo Limited | Professional & scientific | 2019 |
| Arcline Design+Associates Ltd | Professional & scientific | 2025 |
| Arctic Research & Development Ltd | Professional & scientific | 2025 |
| Arcus Electrics Ltd | Construction | 2012 |
| Ardlin Systems Limited | Information & communication | 2004 |
| Ardlin Technologies Limited | Information & communication | 2006 |
| Area Seventeen Limited | Information & communication | 1999 |
| Area Technologies Holdings Limited | Administrative & support | 2021 |
| Area Technologies Limited | Administrative & support | 2015 |
| Arelas Limited | Arts & recreation | 2014 |
| Areyte Limited | Professional & scientific | 2022 |
| Argus Bidco Limited | Financial services | 2018 |
| Argus Midco Limited | Financial services | 2018 |
| Argus Topco Limited | Financial services | 2018 |
| Argyle Electrical Services Limited | Construction | 2004 |
| Arjun Krishnan Limited | Real estate | 2024 |
| ARK Caravans and Trailers Ltd | Manufacturing | 2021 |
| Ark.K Construction Ltd | Construction | 2022 |
| Armada Consultancy Limited | Information & communication | 2009 |
| Armserve Ltd | Construction | 2021 |
| Arnold Support Services Limited | Information & communication | 2001 |
| Arnwood Management Company Limited | Real estate | 1998 |
| Aroma Wokingham Limited | Hospitality | 2026 |
| Arora Invest Ltd | Real estate | 2026 |
| Arra Investments Ltd | Real estate | 2019 |
| Arrogon Ltd | Professional & scientific | 2007 |
| Arrow Support Limited | Health & social care | 2008 |
| Art Black Studio Limited | Professional & scientific | 2018 |
| Art Gloria Plumbing Limited | Construction | 2024 |
| Artemis Safari Limited | Administrative & support | 2017 |
| Artful Rabbit Ltd | Arts & recreation | 2026 |
| Arthur Roberts Consultants Ltd | Professional & scientific | 2012 |
| Arthur Roberts Properties Limited | Real estate | 2022 |
| Artificial Ventures Ltd | Information & communication | 2024 |
| Artigiano Group Ltd | Construction | 2025 |
| ARW Property Rental Ltd | Real estate | 2024 |
| Arya Digital Solutions Ltd | Information & communication | 2026 |
| Aryan Software Solutions Limited | Information & communication | 2015 |
| Arytrades Ltd | Information & communication | 2024 |
| Asar Hospitality Ltd | Hospitality | 2025 |
| Asater Consultancy Services Limited | Professional & scientific | 2008 |
| Ascend Media Collective Ltd | Professional & scientific | 2025 |
| Ascension Property Development & Construction Ltd | Construction | 2024 |
| Ascent 100 Limited | Health & social care | 2021 |