| Achieve Property Management Limited | Construction | 2017 |
| Achim & Simon Properties Ltd | Real estate | 2024 |
| ACL Electrical Services Ltd | Construction | 2023 |
| ACL Roofing Ltd | Construction | 2024 |
| ACL Roofs Ltd | Construction | 2025 |
| ACM Contractors (Nottingham) Limited | Construction | 2007 |
| ACM Driveways & Patios Ltd | Construction | 2016 |
| ACM Leisure Limited | Arts & recreation | 2020 |
| Acomb Homes Ltd | Real estate | 2022 |
| Acorn Building Services (Midlands) Limited | Construction | 2017 |
| Acorn CR Limited | Financial services | 2026 |
| Acorn ELF Ltd | Information & communication | 2021 |
| Acorn Housing Solutions Limited | Health & social care | 2020 |
| Acorn LE Limited | Financial services | 2026 |
| Acorn Narrowboats Limited | Manufacturing | 2023 |
| Acorn Property Solutions Limited | Real estate | 2016 |
| Acorn Tax Services Limited | Professional & scientific | 2023 |
| Acorn Work Winning Services Ltd | Professional & scientific | 2019 |
| ACP Interiors Limited | Construction | 2019 |
| Acquiescence Ventures Ltd | Professional & scientific | 2022 |
| Acquisition Boost Ltd | Real estate | 2022 |
| Acres Engineering Limited | Manufacturing | 2002 |
| Acrimony Limited | Health & social care | 2025 |
| ACS Contractors Limited | Construction | 2018 |
| ACS Mortgages Limited | Financial services | 2017 |
| Action Desk Systems Limited | Professional & scientific | 1990 |
| Action Infinite Limited | Information & communication | 2021 |
| ACTION4FAMILIES CIC | Education | 2020 |
| Actionsolve Limited | Information & communication | 2023 |
| Activ Enterprise Ltd | Wholesale & retail | 2015 |
| Active Commuting Consulting Limited | Administrative & support | 2017 |
| Active Consult Limited | Information & communication | 2016 |
| Active EPC Limited | Real estate | 2023 |
| Active Fire Safety Solutions Ltd | Public administration | 2019 |
| Active Heart Ltd | Health & social care | 2023 |
| Active Support Limited | Health & social care | 2013 |
| Activebodies Limited | Health & social care | 2017 |
| Activeplan Holdings Limited | Financial services | 2017 |
| Activeplan Retail Limited | Information & communication | 2017 |
| Acton Building Company Limited | Construction | 2016 |
| Acumen Holdings Limited | Real estate | 2009 |
| Acumentum Limited | Information & communication | 2014 |
| Acura Wellness Ltd | Education | 2023 |
| Acute Business Advisory Ltd | Other services | 2021 |
| ACW Business Solutions Ltd | Information & communication | 2024 |
| AD Constructions (Midlands) Limited | Construction | 2019 |
| AD Decorators Derbyshire Limited | Construction | 2014 |
| AD Dent Limited | Health & social care | 2021 |
| AD Driveways Limited | Construction | 2025 |
| AD Football Coaching Ltd | Arts & recreation | 2022 |
| AD Haulage Ltd | Transport & logistics | 2020 |
| AD Lighting (Derby) Limited | Wholesale & retail | 2012 |
| AD Lubertatem Ltd | Transport & logistics | 2021 |
| AD Ostium Ltd | Other services | 2021 |
| AD Savvy Ltd | Professional & scientific | 2024 |
| AD Style & Beauty Ltd | Other services | 2019 |
| Adam Barber Derby Limited | Other services | 2024 |
| Adam Drummond Engineering Limited | Professional & scientific | 2026 |
| Adam J Tuck Limited | Financial services | 2021 |
| Adam Mckayley Ltd | Other services | 2019 |
| Adam's Nest Ltd | Manufacturing | 2022 |
| Adamclem Property Limited | Real estate | 2024 |
| Adameq Ltd | Transport & logistics | 2018 |
| Adams Aviation Supply Company Limited | Wholesale & retail | 1968 |
| Adams Bullen Construction Ltd | Construction | 2016 |
| Adaptive Creative Consulting Ltd | Information & communication | 2017 |
| Adaptive DCS Ltd | Wholesale & retail | 2023 |
| ADAPTIVE22 Ltd | Information & communication | 2024 |
| Adastra Restaurants Limited | Hospitality | 2024 |
| Addclad Industrial Cladding Limited | Construction | 2009 |
| Addict Cleaners Limited | Administrative & support | 2025 |
| Addictive Merchandise Limited | Wholesale & retail | 2007 |
| Additive Manufacturing Centre of Excellence Ltd | Manufacturing | 2021 |
| Addmonte Ltd | Information & communication | 2013 |
| Addo Base Serviced Accommodation Ltd | Hospitality | 2022 |
| Addqual Ltd | Professional & scientific | 2015 |
| Addressme Ltd | Real estate | 2023 |
| Addrex.Co Ltd | Information & communication | 2026 |
| Addvance IT Holdings Limited | Financial services | 2021 |
| Adelard Solutions Limited | Financial services | 2025 |
| Adeshor Limited | Health & social care | 2014 |
| Adfan Limited | Real estate | 1996 |
| Adgage Limited | Information & communication | 2010 |
| Adgp Limited | Real estate | 2024 |
| ADH Building Services Limited | Construction | 2010 |
| ADH Homes Limited | Construction | 2021 |
| Adhara Education Ltd | Education | 2020 |
| Adhdmatters Ltd | Health & social care | 2025 |
| Adhithi Ventures Limited | Real estate | 2026 |
| Adiabatic Service Limited | Manufacturing | 2021 |
| Adil Barber Ltd | Other services | 2025 |
| Adil Enterprises & Co UK Limited | Wholesale & retail | 2023 |
| Adil Rafique Limited | Transport & logistics | 2024 |
| Aditya Finance Ltd | Real estate | 2025 |
| ADJ Technical Ltd | Professional & scientific | 2011 |
| ADL Healthcare Limited | Administrative & support | 2006 |
| ADM Investment Group Ltd | Financial services | 2020 |
| Admcs Limited | Real estate | 2024 |
| Adminityservices Limited | Information & communication | 2025 |
| Admirals Wood (LOT 2) Management Company Limited | Households | 2014 |