| AD Shorrock Ltd | Manufacturing | 2012 |
| Ad.Building Services Limited | Construction | 2025 |
| AD3 Holdings (Leeds) Limited | Financial services | 2023 |
| Adam & Co. (UK) Ltd | Wholesale & retail | 2019 |
| Adam & SON News & Convenience Ltd | Wholesale & retail | 2026 |
| Adam (NW) Ltd | Health & social care | 2012 |
| Adam Design Studio Ltd | Other services | 2016 |
| Adam Gray Physiotherapy Limited | Health & social care | 2026 |
| Adam Jones and Sons (Blackheath) Limited | Transport & logistics | 1966 |
| Adam Little Boxing Ltd | Arts & recreation | 2022 |
| Adam Raymond Limited | Information & communication | 2022 |
| Adam Wing Films Ltd. | Information & communication | 2016 |
| Adam's Locum Ltd | Health & social care | 2011 |
| Adam+Gary Limited | Administrative & support | 2023 |
| Adameesa Ltd | Wholesale & retail | 2020 |
| Adamh & Eden Ltd | Wholesale & retail | 2025 |
| Adamplify Limited | Professional & scientific | 2026 |
| Adams Polish Supermarket Limited | Wholesale & retail | 2024 |
| Adamsbridge UK Limited | Information & communication | 2013 |
| Adaptability Occupational Therapy Services Ltd | Health & social care | 2025 |
| Adar Trans Services Ltd | Transport & logistics | 2019 |
| ADB Engineering Services Limited | Administrative & support | 2015 |
| ADB Preston Limited | Construction | 2016 |
| ADB Property Developments Limited | Construction | 2014 |
| Adbc Preston Limited | Transport & logistics | 2018 |
| Adbluerepairs Ltd | Wholesale & retail | 2026 |
| ADC Management Limited | Real estate | 2015 |
| Addblast Contracts Ltd | Wholesale & retail | 2011 |
| Additae Ltd | Administrative & support | 2017 |
| Addlestone Beaconsfield Limited | Real estate | 2025 |
| Addlestone Gerrards Cross Limited | Real estate | 2025 |
| Addlestone Ltd | Construction | 2021 |
| Adealon (Group Legal Services) Limited | Professional & scientific | 2000 |
| Adealon (UK) Limited | Professional & scientific | 1998 |
| Adelantar Limited | Wholesale & retail | 2020 |
| Adelphi Kebab House Ltd | Hospitality | 2024 |
| Adelphi Management Services Ltd | Real estate | 2015 |
| Adelphi Self Storage Limited | Transport & logistics | 2003 |
| Adeney Estates Limited | Hospitality | 2015 |
| Adepic Pictures Ltd | Information & communication | 2025 |
| Adeptli Ltd | Professional & scientific | 2022 |
| Adhd Health Solutions Limited | Professional & scientific | 2025 |
| Adhoc Support CIC | Information & communication | 2025 |
| ADI Contracts Limited | Professional & scientific | 2010 |
| Adicio Solutions Ltd | Information & communication | 2011 |
| Adiseal Ltd | Wholesale & retail | 2011 |
| Adjack Developments Ltd | Real estate | 2013 |
| Adjh Honeypot Ltd | Real estate | 2026 |
| Adjusting Limited | Financial services | 2018 |
| ADK Environmental Management Limited | Professional & scientific | 2005 |
| Adkbk Limited | Professional & scientific | 2020 |
| Adkdp Limited | Manufacturing | 2025 |
| Adkirk Law Employment Services Limited | Administrative & support | 2015 |
| Adkirk Law Inc Limited | Professional & scientific | 2014 |
| Adkirk Law Limited | Professional & scientific | 2012 |
| Admin Kismat Ltd | Administrative & support | 2025 |
| Adminjim Ltd | Public administration | 2026 |
| Admirable ZE Trade Ltd | Wholesale & retail | 2024 |
| ADR Mediation & Training C.I.C. | Other services | 2013 |
| ADR Services & Solutions Limited | Administrative & support | 2015 |
| Adrenova Ltd | Health & social care | 2024 |
| Adrian Cope Project Management Limited | Professional & scientific | 2009 |
| Adrian&Elena Transport Ltd | Transport & logistics | 2021 |
| Adriana Immigration Services Limited | Other services | 2017 |
| Adriancox Trans Ltd | Transport & logistics | 2018 |
| ADS Electrical & Mechanical Limited | Construction | 2012 |
| ADS Visuals Limited | Real estate | 2024 |
| Adsamoj Careers Services Ltd | Administrative & support | 2022 |
| Adstock Investments Limited | Real estate | 2022 |
| Aduki Ltd | Real estate | 2022 |
| ADV Trading Limited | Wholesale & retail | 2025 |
| Advance Clothing Management Limited | Wholesale & retail | 2009 |
| Advance Commercials Limited | Wholesale & retail | 2013 |
| Advance Interiors Limited | Construction | 2025 |
| Advance Renovations Limited | Real estate | 2016 |
| Advance Scaffolding (Lancashire) Limited | Administrative & support | 1998 |
| Advance Scaffolding Solutions Limited | Administrative & support | 2018 |
| Advance Textile Products Limited | Wholesale & retail | 2004 |
| Advanced Access Scaffolding (NW) Limited | Administrative & support | 2014 |
| Advanced Electrical Solutions ( SO ) Ltd | Construction | 2021 |
| Advanced Home Care Limited | Health & social care | 2006 |
| Advanced Interiors Ltd | Construction | 2020 |
| Advanced Interiors Management Ltd | Professional & scientific | 2025 |
| Advanced Marketing Solutions Limited | Information & communication | 2023 |
| Advanced Motorsport Ltd | Wholesale & retail | 2019 |
| Advanced Print Solutions Ltd | Manufacturing | 2010 |
| Advanced Techniques Limited | Administrative & support | 2026 |
| Advantage Trading Ltd | Wholesale & retail | 2023 |
| ADVANTAGE88 Limited | Professional & scientific | 2021 |
| Advent Print & Design Ltd | Professional & scientific | 2014 |
| Adventures in Adland Limited | Professional & scientific | 2024 |
| Advertising for Business Ltd | Professional & scientific | 2015 |
| ADW Consultants Limited | Professional & scientific | 2017 |
| ADW Group (NW) Limited | Construction | 2026 |
| ADY Smith OFF Road Experience Ltd | Arts & recreation | 2016 |
| Adyama Makali Limited | Health & social care | 2024 |
| Aedgaruk Limited | Information & communication | 2023 |
| Aegean Blue Villas Limited | Construction | 2002 |
| Aegis Crowd Safety Limited | Administrative & support | 2026 |
| Aegis Rail Holdings Limited | Financial services | 2020 |