| Advanced Control Technology Limited | Professional & scientific | 2021 |
| Advanced Creations Ltd | Information & communication | 2025 |
| Advanced Creativity for Export Ltd | Wholesale & retail | 2026 |
| Advanced Damp Proofing Ltd | Construction | 2018 |
| Advanced Dawood Comparisons Company Ltd | Other services | 2024 |
| Advanced Defence Technologies Ltd | Information & communication | 2024 |
| Advanced Domestics Ltd | Other services | 2025 |
| Advanced Driver Assistance Systems(Adas) Limited | Wholesale & retail | 2026 |
| Advanced Driving Tuition Limited | Education | 2018 |
| Advanced Engineering Consultants Group UK Ltd | Construction | 2020 |
| Advanced Excellence Network Ltd | Wholesale & retail | 2025 |
| Advanced Faces Limited | Health & social care | 2025 |
| Advanced Farming Ltd | Agriculture & fishing | 2021 |
| Advanced Fire Alarms Ltd | Construction | 2010 |
| Advanced Green Solutions Limited | Construction | 2011 |
| Advanced Hair Technology Limited | Other services | 1993 |
| Advanced Hair Transplants LLP | | 2011 |
| Advanced Integration Technology UK Limited | Manufacturing | 2026 |
| Advanced IOT Ltd | Wholesale & retail | 2019 |
| Advanced Legal Consultants Limited | Professional & scientific | 2014 |
| Advanced Life Support Group | Education | 2002 |
| Advanced Media Solutions Limited | Information & communication | 2019 |
| Advanced Photo Ltd | Professional & scientific | 2024 |
| Advanced Process Integration Limited | Professional & scientific | 2021 |
| Advanced Property Care Ltd | Construction | 2018 |
| Advanced Protective Packaging Ltd | Manufacturing | 1986 |
| Advanced Services(Uk) Ltd | Health & social care | 2016 |
| Advanced Solutions for Trading Ltd | Other services | 2025 |
| Advanced Study Ltd | Information & communication | 2019 |
| Advanced Trade Solutions Limited | Wholesale & retail | 2019 |
| Advanced Travel Partners International Limited | Professional & scientific | 2002 |
| Advanced Travel Partners UK Ltd | Administrative & support | 1990 |
| Advanced Vehicle Technicians Limited | Wholesale & retail | 2003 |
| Advanex Ltd | Wholesale & retail | 2017 |
| Advania Dormant Limited | Information & communication | 2001 |
| Advania Holdings UK Limited | Professional & scientific | 2016 |
| Advania UK (CCS) Limited | Information & communication | 2002 |
| Advania UK (Servium) Limited | Information & communication | 2009 |
| Advania UK Limited | Information & communication | 1998 |
| Advania UK SMB Limited | Information & communication | 2002 |
| Advanstar Communications (U.K.) Limited | Information & communication | 1996 |
| Advant Consultancy Ltd | Information & communication | 2014 |
| Advanta Estates Ltd | Real estate | 2025 |
| Advantage Business Consultancy Limited | Professional & scientific | 2019 |
| Advantage Business Management Limited | Administrative & support | 2017 |
| Advantage Cars Astley Ltd | Wholesale & retail | 2019 |
| Advantage Digital Outdoor Media Limited | Professional & scientific | 2002 |
| Advantage Dyslexia Ltd | Education | 2021 |
| Advantage Growth Fund (General Partner) Limited | Financial services | 2002 |
| Advantage Infrastructure Group Ltd | Professional & scientific | 2023 |
| Advantage Infrastructure Ltd | Professional & scientific | 2022 |
| Advantage Technical Ltd | Construction | 2023 |
| Advantagious Ltd | Real estate | 2025 |
| Advantax AI Limited | Professional & scientific | 2025 |
| Advantia Card Ltd | Financial services | 2021 |
| Advantis OP EX Limited | Professional & scientific | 2016 |
| Advanturalabs Ltd | Wholesale & retail | 2025 |
| Advasia Limited | Wholesale & retail | 2025 |
| Advd Ltd | Professional & scientific | 2025 |
| Advent 1 Management Company Limited | Households | 2009 |
| Advent 2 & 3 Management Company Limited | Households | 2009 |
| Advent Domiciliary Services Ltd | Health & social care | 2023 |
| Advent for Supplies Ltd | Wholesale & retail | 2026 |
| Advent Wholesale Ltd | Transport & logistics | 2007 |
| Adventum Wealth Ltd | Real estate | 2015 |
| Adventure Clues Ltd | Information & communication | 2023 |
| Adventure Parc Snowdonia Limited | Arts & recreation | 2012 |
| Advera OS Ltd | Households | 2025 |
| Adverix Ltd | Professional & scientific | 2026 |
| Advertising Billboards Ltd | Wholesale & retail | 2025 |
| Advertising Glass Ltd | Professional & scientific | 2024 |
| Advertising-Consulting Ltd | Professional & scientific | 2026 |
| Advertmetrics Ltd | Information & communication | 2019 |
| Advertprise Limited | Wholesale & retail | 2025 |
| Advg Holdings Limited | Financial services | 2023 |
| Advg Properties Limited | Real estate | 2024 |
| Advice for Renters Limited | Professional & scientific | 1989 |
| Adview Media Ltd | Professional & scientific | 2024 |
| Adviso Ltd | Information & communication | 2017 |
| Advisory 9 Ltd | Education | 2025 |
| Advizzo Ltd | Information & communication | 2015 |
| Advokatai Ltd | Professional & scientific | 2012 |
| Advoza Ltd | Wholesale & retail | 2025 |
| Adwa Aldarab Limited | Wholesale & retail | 2025 |
| Adwa Aleasimih Almutakamilat Lilaemal Ltd | Wholesale & retail | 2025 |
| Adwa Alsahra Almutaqadima Ltd | Wholesale & retail | 2026 |
| ADX Consultants Limited | Real estate | 2020 |
| ADY Efraim Ltd | Construction | 2020 |
| ADY Soft Furnishing Ltd | Wholesale & retail | 2025 |
| Ady&Cory Manchester Construction&Electrical Services Ltd | Energy | 2026 |
| Adyon Limited | Professional & scientific | 2022 |
| Adyre Limited | Wholesale & retail | 2026 |
| Adzap Ltd | Information & communication | 2025 |
| Adzeno Limited | Professional & scientific | 2025 |
| Adziv Digital Ltd | Wholesale & retail | 2023 |
| Adziyo Ltd | Wholesale & retail | 2022 |
| AE Accountancy Ltd | Professional & scientific | 2021 |
| AE Dent Limited | Health & social care | 2012 |
| AE Freight Consultancy Ltd | Transport & logistics | 2026 |
| AE International Limited | Financial services | 1956 |