| Adian UK Ltd | Wholesale & retail | 2019 |
| Adiaru Consultancy Limited | Information & communication | 2025 |
| Adiboye Consulting Ltd | Professional & scientific | 2014 |
| Adire Ltd | Information & communication | 2018 |
| Aditi Care Limited | Health & social care | 2019 |
| Adlit Investments Limited | Administrative & support | 2008 |
| Adlocks Locksmiths Ltd | Administrative & support | 2021 |
| Admiral Corporation GB Limited | Construction | 1996 |
| Admiral Homes U.K. Limited | Construction | 2020 |
| Admiral Pest Management Limited | Other services | 1986 |
| Admiral Properties Limited | Construction | 2011 |
| Adml Limited | Administrative & support | 1999 |
| Adnah Healthcare Limited | Administrative & support | 2018 |
| ADO Accounting Ltd | Professional & scientific | 2019 |
| Adom Social Care Limited | Health & social care | 2025 |
| Adoxa Construction Ltd | Construction | 2026 |
| Adrians Holdings Ltd | Professional & scientific | 2020 |
| Adrians Lettings Limited | Real estate | 2017 |
| Adrians Property Services Limited | Real estate | 2013 |
| Adroit Electrical Services Ltd | Construction | 2008 |
| ADS Energy Ltd | Construction | 2025 |
| Adsam Healthcare Ltd | Public administration | 2023 |
| Adsfind Limited | Professional & scientific | 2016 |
| Adsum Digital Ltd | Information & communication | 2020 |
| Adullam Consortium Limited | Other services | 2024 |
| Adunwa Ltd | Wholesale & retail | 2019 |
| Advance Fitness Studio Ltd | Health & social care | 2019 |
| Advance Property Management (SE) Ltd | Wholesale & retail | 2002 |
| Advance Property Rental Limited | Real estate | 2018 |
| Advance Wealth Limited | Administrative & support | 2008 |
| Advanced Asbestos Contractors (South East) Limited | Water & waste | 2009 |
| Advanced Industrial Roofing and Cladding Solutions Limited | Construction | 2012 |
| Advanced Plumbing Systems Limited | Construction | 2012 |
| Advanced Roofing and Cladding Limited | Construction | 2024 |
| Advanced Specialist Services Limited | Construction | 2013 |
| Advancing Client Engagement Ltd | Manufacturing | 2017 |
| Advent Claims Limited | Financial services | 2016 |
| Advent Consulting Solutions Limited | Information & communication | 2019 |
| Advent Insurance Management Limited | Information & communication | 2015 |
| Advico Technology UK Limited | Administrative & support | 2017 |
| Advizio PG UK Limited | Real estate | 2023 |
| Advoyager Limited | Information & communication | 2024 |
| Adway Heat Pumps Ltd | Manufacturing | 2020 |
| ADY & Co Consults Ltd | Health & social care | 2026 |
| Aedificem Ltd | Real estate | 2018 |
| AEG 1440 LP | | 2020 |
| Aegean IT Solutions Ltd | Information & communication | 2017 |
| Aegis Contracting Ltd | Administrative & support | 2024 |
| AEL Consulting Limited | Professional & scientific | 1999 |
| Aeon Solutions Ltd | Professional & scientific | 2015 |
| AEP Medical Services Ltd | Health & social care | 2023 |
| Aerial Icon Limited | Professional & scientific | 2017 |
| Aerial Sport and Fitness Limited | Arts & recreation | 2023 |
| Aerial-Uk Ltd | Transport & logistics | 2024 |
| Aerolyse Environmental Ltd | Professional & scientific | 2026 |
| Aerosolar Ltd | Professional & scientific | 2022 |
| Aether Group Limited | Wholesale & retail | 2024 |
| Aethmerch Limited | Wholesale & retail | 2025 |
| Aeuro Ltd | Information & communication | 2015 |
| Aeurox Trading Ltd | Wholesale & retail | 2018 |
| AF Education Limited | Education | 2015 |
| AF Life Shield Ltd | Professional & scientific | 2022 |
| Afede Health Beauty & Wellness Limited | Wholesale & retail | 2015 |
| Affinity Essex Ltd | Wholesale & retail | 2025 |
| Affinity Martial Arts Ltd | Arts & recreation | 2026 |
| Affinity Security Services Limited | Public administration | 2017 |
| Affordable Cleaning and Painting Ltd Limited | Construction | 2025 |
| Affordable Hard Woods Limited | Wholesale & retail | 2019 |
| AFL Casa UK Ltd | Financial services | 2023 |
| Afrik Fest Events Ltd | Arts & recreation | 2025 |
| Afriluxe Limited | Wholesale & retail | 2025 |
| Afro-Ethnic Trends Limited | Wholesale & retail | 2016 |
| Afrocado Ltd | Wholesale & retail | 2024 |
| AG Flooring Consultancy Ltd | Wholesale & retail | 2018 |
| Aga-Tom Trans Ltd | Transport & logistics | 2020 |
| Agasee Law Associates Limited | Professional & scientific | 2023 |
| AGC Infracon PVT Ltd | Construction | 2024 |
| AGC Living Ltd | Real estate | 2024 |
| Agcode Ltd | Information & communication | 2022 |
| Agility Care Ltd | Administrative & support | 2016 |
| Agility Limited | Professional & scientific | 2020 |
| Aginergy Limited | Professional & scientific | 2020 |
| Agir Ltd | Real estate | 2020 |
| Agius Services Limited | Administrative & support | 2019 |
| AGL Solutions Limited | Financial services | 2018 |
| Agop Auto Group Ltd | Wholesale & retail | 2024 |
| AGP Haulage & Plant Hire Ltd | Transport & logistics | 2020 |
| AGR Chauffeurs Limited | Transport & logistics | 2024 |
| Agribay Limited | Information & communication | 2016 |
| Agromel UK Limited | Agriculture & fishing | 2024 |
| AGS Properties Ltd | Construction | 2013 |
| Aguk Trustee Limited | Extraterritorial | 2025 |
| Agwood Ltd | Wholesale & retail | 2022 |
| AH Structural Design Ltd | Professional & scientific | 2019 |
| AHC Construction and Consultancy Ltd | Construction | 2015 |
| AHC Lettings Ltd | Hospitality | 2022 |
| AHC Property Consultants Limited | Administrative & support | 2009 |
| AHE Group Limited | Construction | 2007 |
| AHEAD4 Limited | Information & communication | 2000 |
| Ahill Construction Ltd | Construction | 2025 |