| Algorial Trading Ltd | Wholesale & retail | 2019 |
| ALI Barber (Maidstone) Limited | Other services | 2023 |
| Alice Childcare Services Ltd | Education | 2023 |
| Alice Dartnell Limited | Wholesale & retail | 2019 |
| Alicy Properties Ltd | Real estate | 2018 |
| Aligned Talent Group Ltd | Administrative & support | 2026 |
| Aligntech Consulting Ltd | Information & communication | 2025 |
| Alin & Maya Logistics Limited | Transport & logistics | 2020 |
| Alisons Driving School Limited | Education | 2024 |
| Alka Logistics Limited | Transport & logistics | 2014 |
| ALL Carpentry Services Ltd | Construction | 2025 |
| ALL Concierge Limited | Administrative & support | 2022 |
| ALL Innovations Ltd | Financial services | 2023 |
| ALL Kent Roofing HD Ltd | Construction | 2025 |
| ALL Merchant Solutions Ltd | Wholesale & retail | 2018 |
| ALL Round Fitness Ltd | Wholesale & retail | 2025 |
| ALL Saints Autocentre Limited | Wholesale & retail | 2022 |
| ALL Saints MOT & Service Centre Ltd | Wholesale & retail | 2026 |
| ALL Season Training Camp Ltd | Arts & recreation | 2025 |
| ALL Steel Services (UK) Ltd | Other services | 2012 |
| ALL Successful Group Ltd | Financial services | 2025 |
| ALL Things Audio (at Audio) Ltd | Information & communication | 2022 |
| ALL Things Carpentry Ltd | Manufacturing | 2025 |
| ALL Type Flooring (South East) Ltd | Extraterritorial | 2025 |
| ALL Type Flooring Ltd | Construction | 2019 |
| ALL Type Roofing Structure Ltd | Construction | 2020 |
| ALL Type Valves Limited | Wholesale & retail | 1999 |
| Allegiance Services Limited | Manufacturing | 2016 |
| Allen Carpets Limited | Wholesale & retail | 2003 |
| Allen Drylining Services Ltd | Construction | 2023 |
| Alliance Concrete Pumps Limited | Transport & logistics | 2020 |
| Allied Business Support Limited | | 2009 |
| Allied&Allan Services Limited | Transport & logistics | 2019 |
| Allien Security International Ltd | Administrative & support | 2020 |
| Allmivida Ltd | Wholesale & retail | 2023 |
| Alloise Limited | Information & communication | 2008 |
| Allpro Installations Limited | Construction | 2017 |
| Allset Retail Ltd | Wholesale & retail | 2025 |
| Almond House Properties Limited | Real estate | 2019 |
| Alolar Ltd | Hospitality | 2024 |
| Alooma Technologies Ltd | Information & communication | 2022 |
| ALP Schools Limited | Education | 2020 |
| Alpha Auto Ltd | Professional & scientific | 2024 |
| Alpha Controls LDN Ltd | Construction | 2022 |
| Alpha Facilities Management Limited | Administrative & support | 2026 |
| Alpha Perspectives Ltd | Information & communication | 2024 |
| Alpha Walls Construction Limited | Construction | 2020 |
| Alphabeta Contracting Limited | Construction | 2018 |
| Alpine Construction Group Ltd | Construction | 2017 |
| Alpine Grove Limited | Households | 2000 |
| Altunsari Limited | Hospitality | 2024 |
| Altus Operational Consulting LLP | | 2013 |
| Alumen Windows and Doors Limited | Manufacturing | 2024 |
| Alzheimer's & Dementia Support Services | Health & social care | 2017 |
| AM Building UK Ltd | Administrative & support | 2017 |
| AM Drylining Ltd | Construction | 2024 |
| Amaanat Limited | Information & communication | 2013 |
| Amaco UK Drylining Ltd | Construction | 2021 |
| Amafar Limited | Professional & scientific | 2016 |
| Amanni Transport Ltd | Transport & logistics | 2026 |
| Amariah Consulting Limited | Professional & scientific | 2013 |
| Amariei Construction Ltd | Administrative & support | 2022 |
| Amax Estates & Property Services Ltd | Real estate | 2002 |
| Amazone Holdings Ltd | Construction | 2025 |
| Amazone Homes Limited | Real estate | 2025 |
| Amazone Properties Limited | Real estate | 2025 |
| Ambar Associates Limited | Administrative & support | 2023 |
| Ambareen Construction Ltd | Construction | 2013 |
| Amber Polishing Ltd | Construction | 2019 |
| Ambiguous Associates Ltd | Administrative & support | 2014 |
| Ambury Estates Ltd | Households | 2025 |
| Ambury Installations Ltd | Construction | 2013 |
| Ameg Construction Ltd | Construction | 2025 |
| Ameliorate Commercial Finance Management Limited | Professional & scientific | 2011 |
| Amen Resources Ltd | Professional & scientific | 2019 |
| Amerea International Inc | | 1985 |
| Amidst the Chaos of Discordianism, WE Find Wisdom, Freedom, and Laughter. Recognise the Finite, for Even in Disorder, OUR Scope IS Beautifully Limited | Arts & recreation | 2024 |
| AMK Rail Consultancy Ltd | Construction | 2020 |
| Amka Homes Ltd | Administrative & support | 2017 |
| AML Expert Consultant Solutions Ltd | Professional & scientific | 2016 |
| Amma Property Limited | Real estate | 2023 |
| Ammax Limited | Construction | 2011 |
| Ammica Ltd | Construction | 2015 |
| Amolab Services Limited | Public administration | 2018 |
| Amora Flowers Ltd | Wholesale & retail | 2020 |
| Amosco Properties Ltd | Real estate | 2020 |
| Amoscotech Ltd | Information & communication | 2017 |
| Amour Propre Ltd | Other services | 2021 |
| AMP Enterprise Ltd | Information & communication | 2007 |
| Ampere Electrical Contractors Ltd | Construction | 2022 |
| Amplio (White Horse Inn) Limited | Construction | 2025 |
| Ampquest Limited | Construction | 2010 |
| Amra Consulting Limited | Professional & scientific | 2015 |
| AMS Spectrum Property Ltd | Real estate | 2026 |
| Amsterdam Way Apartments Ltd | Households | 2021 |
| AMT Choice Ltd | Administrative & support | 2019 |
| Amtrak Express Parcels (UK) Limited | Extraterritorial | 2008 |
| Amukpe Ltd | Health & social care | 2023 |
| Amurphyprojects Ltd | Real estate | 2024 |
| AMZ Recycling&Cleaning Limited | Wholesale & retail | 2020 |