| Arnold Property Group Ltd | Real estate | 2025 |
| Arnolds Trading Group Ltd | Wholesale & retail | 2026 |
| Arnotransa Ltd | Transport & logistics | 2019 |
| Aroma Oriental Limited | Hospitality | 2017 |
| Arrans Limited | Professional & scientific | 2006 |
| Arrow Storage Ltd | Arts & recreation | 2025 |
| Arrowhead Target Faces Limited | Wholesale & retail | 2004 |
| Arrowthorn Management Limited | Wholesale & retail | 2011 |
| Art Facade Ltd | Construction | 2025 |
| Art of Brilliance Limited | Administrative & support | 2008 |
| Art Paint Consulting Ltd | Construction | 2026 |
| AS Road Surfacing Ltd | Construction | 2025 |
| Asbo-Rc Ltd | Wholesale & retail | 2021 |
| ASC Logistics Limited | Transport & logistics | 2020 |
| Ascend Personnel Limited | Administrative & support | 2016 |
| Ascent Creation Limited | Professional & scientific | 2023 |
| Ascott Analytical Equipment Limited | Manufacturing | 1991 |
| ASD Construction Group Ltd | Construction | 2025 |
| ASG Electrical (Solutions) Limited | Construction | 2009 |
| Ashcor Tarmacadam and Paving Ltd | Construction | 2023 |
| Ashford Green Limited | Professional & scientific | 2018 |
| Ashgate Development Services Limited | Construction | 2003 |
| Ashlawn HR Consultancy Limited | Professional & scientific | 2022 |
| Ashleam Properties Limited | Construction | 2018 |
| Ashley Girn Fitness Limited | Wholesale & retail | 2023 |
| Asian Consultancy Enterprise Limited | Wholesale & retail | 2022 |
| Askul Transport Limited | Transport & logistics | 2023 |
| Aspire Aluminium Ltd | Manufacturing | 2019 |
| Aspire Consulting (Holdings) Limited | Professional & scientific | 2008 |
| Aspire Consulting Limited | Professional & scientific | 1996 |
| Aspire Properties Nottingham Limited | Construction | 2024 |
| Aspire Property Management Limited | Real estate | 2022 |
| Assessmee Ltd | Construction | 2021 |
| Asset ARC Limited | Financial services | 2026 |
| Associate Building Contractors Ltd | Administrative & support | 2016 |
| Associated Audio Brands Limited | Transport & logistics | 2022 |
| Associated Vending Services Limited | Other services | 1988 |
| Assured Healthcare Solutions Holdings Ltd | Financial services | 2024 |
| Assured Healthcare Solutions Ltd | Health & social care | 2016 |
| Assured Origin Ltd. | Professional & scientific | 1995 |
| Assured Safety Services Ltd | Construction | 2022 |
| Astro Construction UK Limited | Construction | 2015 |
| Astro Consulting Global Ltd | Construction | 2026 |
| Astute Assess & Collect Ltd | Transport & logistics | 2015 |
| At&P Property Investments Limited | Real estate | 2026 |
| ATB IT Solutions Limited | Information & communication | 2014 |
| Atce Group Limited | Financial services | 2023 |
| Atechnics Limited | Professional & scientific | 2022 |
| Athena Finance Solutions Ltd | Financial services | 2024 |
| Atherstone Contracting Ltd | Construction | 2025 |
| Atkins Property Services Midlands Ltd | Real estate | 2024 |
| Atlantic Fish Bar (Kingbury) Ltd | Wholesale & retail | 2017 |
| Atlantis Hot TUB Hire Ltd | Administrative & support | 2020 |
| Atlas Assessments Ltd | Other services | 2023 |
| Atlas Motor Repairs Limited | Manufacturing | 2014 |
| Atlas Property Investments Group Limited | Real estate | 2023 |
| Atlas Tattoo Supplies Ltd | Wholesale & retail | 2019 |
| Atms Holdings Ltd | Real estate | 2022 |
| Attica Land & Development Ltd | Construction | 2025 |
| Atwain Solutions Ltd | Wholesale & retail | 2024 |
| Aurora Taverns Limited | Hospitality | 2025 |
| Auso Ltd | Wholesale & retail | 2012 |
| Auto Box Logistics Limited | Transport & logistics | 2013 |
| Autolift U.K. Ltd | Manufacturing | 2025 |
| Autonew Limited | Wholesale & retail | 2025 |
| Autowire Ltd | Wholesale & retail | 2024 |
| Auxin Ventures Ltd | Information & communication | 2025 |
| Avalanche Technology Ltd | Real estate | 2014 |
| Avalaunch Limited | Wholesale & retail | 2014 |
| Avantgarde Classics Ltd | Wholesale & retail | 2013 |
| AVB Events Ltd | Wholesale & retail | 2025 |
| AVB Services Ltd | Transport & logistics | 2018 |
| Avcom Solutions Limited | Information & communication | 2014 |
| Avenue Tyres Limited | Wholesale & retail | 1997 |
| Avery Products Ltd | Wholesale & retail | 2025 |
| Averys.E.S Limited | Construction | 2018 |
| AVI Midland Ltd | Other services | 2026 |
| Avisio Limited | Extraterritorial | 2018 |
| Avon Brickwork Ltd | Construction | 2025 |
| Avondale Locomotives Limited | Extraterritorial | 2004 |
| Avultra Ltd | Wholesale & retail | 2024 |
| AWP Transport Consultancy Ltd | Professional & scientific | 2025 |
| Awsum Food Ltd | Hospitality | 2023 |
| Awsum Treats Ltd | Hospitality | 2025 |
| Axel Drainage Ltd | Water & waste | 2023 |
| Axelectrical and Co Limited | Construction | 2025 |
| Axiom Engineering Group Ltd | Financial services | 2021 |
| Axiom GB Limited | Professional & scientific | 1999 |
| Axiom GB Services Ltd | Professional & scientific | 2022 |
| Axis Compliance Auditing Services Ltd | Professional & scientific | 2019 |
| Axmr Ltd | Professional & scientific | 2025 |
| AXR Properties Ltd | Real estate | 2021 |
| Ayla Trans Ltd | Transport & logistics | 2022 |
| Aztec Homes Ltd | Real estate | 2019 |
| Aztech Surveying Services Limited | Administrative & support | 2016 |
| B & M Flooring (Midlands) Ltd | Construction | 2020 |
| B & W Electrical Limited | Construction | 2005 |
| B N J Consultants Ltd | Administrative & support | 2009 |
| B P S Fabrication 1 Ltd | Construction | 2018 |
| B&Cr Holdings Ltd | Financial services | 2024 |