| AJG Electrical Ltd | Construction | 2008 |
| AJK Commercial Consulting Ltd | Professional & scientific | 2024 |
| AJL Stone Sales Ltd | Extraterritorial | 2022 |
| AJR Distribution Consultants Ltd | Professional & scientific | 2006 |
| AJS & RT Consulting Limited | Information & communication | 2002 |
| AK Counselling Ltd | Health & social care | 2019 |
| AK Development & Investment Group Limited | Real estate | 2023 |
| AKR Direct Limited | Wholesale & retail | 2025 |
| AL Hadi Truckers Ltd | Transport & logistics | 2025 |
| AL Reza Travel Ltd | Administrative & support | 2020 |
| AL' ILM NUR Limited | Other services | 2017 |
| ALB Enterprises Ltd | Hospitality | 2016 |
| Aldis Builders Ltd | Construction | 2019 |
| ALH Management Ltd | Professional & scientific | 2026 |
| Align Wellness Limited | Wholesale & retail | 2026 |
| Alison Philipson Literacy Limited | Education | 2015 |
| Alister David Wiggan Ltd | Extraterritorial | 2024 |
| ALL About the Doll Limited | Wholesale & retail | 2015 |
| ALL Piped UP Limited | Construction | 2021 |
| ALL Star Ents Ltd | Education | 2012 |
| ALL Star Youth CIC | Education | 2016 |
| ALL Torque Ltd | Hospitality | 2025 |
| Allabout Trade Windows Ltd | Manufacturing | 2018 |
| Allandale's Refurbs (Yorkshire) Limited | Construction | 2017 |
| Allied Capital Limited | Other services | 2016 |
| Alpha Training Ltd | Health & social care | 2024 |
| ALPHA1 Housing Limited | Construction | 2024 |
| ALPHA369 Ltd | Wholesale & retail | 2026 |
| Alpine Grounds Maintenance Limited | Administrative & support | 2016 |
| Alpine Tyres Limited | Wholesale & retail | 2024 |
| ALT Theory Limited | Professional & scientific | 2020 |
| Altanova Ltd | Health & social care | 2026 |
| Altash Healthcare Limited | Health & social care | 2013 |
| ALTEA1 Ltd | Professional & scientific | 2016 |
| Altreka CIC | Education | 2023 |
| Altrigen Solutions Limited | Information & communication | 2000 |
| Alue CLO Limited | Wholesale & retail | 2026 |
| Alvin's Fish Bar Ltd | Hospitality | 2016 |
| Amazing People Recruitment Limited | Administrative & support | 2024 |
| AMB Business Limited | Real estate | 2018 |
| Amberhill Investments Ltd | Professional & scientific | 2007 |
| Amore Paws Ltd | Extraterritorial | 2020 |
| Amplitude Event Solutions Limited | Other services | 2015 |
| Amtane Limited | Professional & scientific | 2005 |
| Anasheanesu Care Services Limited | Administrative & support | 2017 |
| Andagoat Limited | Professional & scientific | 2019 |
| Andrew Hill Limited | Financial services | 2007 |
| Andrew Rhys Evans Limited | Health & social care | 2007 |
| Andrew Toczek Ltd | Professional & scientific | 2012 |
| Angel Ecommerce Ltd | Information & communication | 2011 |
| Ansell Jones Limited | Manufacturing | 2004 |
| Anthony Martin Interior Design Ltd | Arts & recreation | 2016 |
| Aperture Media Ltd | Professional & scientific | 2018 |
| Apex Motors Bradford Ltd | Wholesale & retail | 2026 |
| Apex Residential Solutions Ltd | Real estate | 2024 |
| Apna Shop Ltd | Wholesale & retail | 2024 |
| Appleby Events Ltd | Professional & scientific | 2015 |
| Approved Leisure Ltd | Wholesale & retail | 2015 |
| AQA2 Properties Ltd | Real estate | 2020 |
| Aqua ROD Lista Drain (UK) Limited | Water & waste | 2008 |
| Aquafoil Ltd | Manufacturing | 2023 |
| AR Wellness Solutions Ltd | Health & social care | 2025 |
| Arbiter Bibendi Limited | Extraterritorial | 2005 |
| ARC Foods Ltd | Hospitality | 2022 |
| ARC Forwarding Ltd | Transport & logistics | 2020 |
| Archerdale (Holdings) Limited | Professional & scientific | 2014 |
| Archerdale Group EOT Limited | Financial services | 2024 |
| Archerdale Limited | Wholesale & retail | 1983 |
| Archis Consulting Ltd | Professional & scientific | 2026 |
| Arista Construction Limited | Construction | 2010 |
| Armstrong & Co Properties Limited | Real estate | 2025 |
| Arsala Enterprises Ltd | Transport & logistics | 2025 |
| Arthur Brear & SON Limited | Construction | 1964 |
| Articulate Drama School Ltd | Administrative & support | 2018 |
| Articulate Productions Ltd | Administrative & support | 2017 |
| Artisan Global Sourcing Ltd | Wholesale & retail | 2022 |
| Artricia Finance Limited | Professional & scientific | 2023 |
| Aryan Motors Limited | Wholesale & retail | 2025 |
| AS Automotive Ltd | Wholesale & retail | 2024 |
| ASA Energy Developments Limited | Construction | 2020 |
| ASC Cartons Group Limited | Manufacturing | 2022 |
| ASC Cartons Holdings Limited | Financial services | 2022 |
| ASC Cartons Limited | Manufacturing | 1981 |
| ASC Direct Limited | Manufacturing | 2007 |
| Ascending Asset Advisors Limited | Other services | 2021 |
| Asdc Agency Ltd | Administrative & support | 2017 |
| ASE Autogate Ltd | Construction | 2001 |
| Ashbrit Care Services Limited | Health & social care | 2017 |
| Ashbrook Renewable Energy Limited | | 2010 |
| Ashcroft Accounting Limited | Professional & scientific | 2013 |
| Asheila Narang Limited | Health & social care | 2009 |
| Ashfield Trading Limited | Wholesale & retail | 2025 |
| Ashlands Fencing Limited | Construction | 2004 |
| Ashley Alice Boutique Limited | Wholesale & retail | 2019 |
| Asima Begum Ltd | Administrative & support | 2025 |
| Assessment and Training SW Consultancy Ltd | Health & social care | 2023 |
| Assure Commercial Finance Ltd | Financial services | 2017 |
| Astel Networking Solutions Limited | Real estate | 2011 |
| Athena Tanning Hair & Beauty Salon Ltd | Other services | 2005 |
| Atmoss Limited | Other services | 2009 |