| ADC UK Development Ltd | Real estate | 2025 |
| ADC UK Properties Ltd | Real estate | 2022 |
| ADD Parmar Ltd | Transport & logistics | 2021 |
| Addcare Health UK Ltd | Health & social care | 2022 |
| Addison Direct Limited | Wholesale & retail | 2024 |
| Addsumvalue Ltd | Education | 2025 |
| ADE Automobiles & Tours Limited | Wholesale & retail | 2020 |
| ADEAFI1 Limited | Health & social care | 2023 |
| Adecyn Limited | Administrative & support | 2018 |
| Adecyn Properties Limited | Real estate | 2020 |
| Adecyn's Group Limited | Financial services | 2022 |
| Ademighty Housing C.I.C. | Administrative & support | 2019 |
| Adept Accounts Services Limited | Professional & scientific | 2020 |
| Adept Fire & Security Systems Limited | Extraterritorial | 2009 |
| Adept Learning Ltd. | Information & communication | 2020 |
| Adept Marketing Services Ltd | Professional & scientific | 2020 |
| Adept Move Ltd | Households | 2019 |
| Adeptio Law (West Midlands) Limited | Financial services | 2024 |
| Adeptio Law Group Limited | Financial services | 2024 |
| Adeptio Law Holdco Limited | Financial services | 2024 |
| Adeptio Law Midco Limited | Financial services | 2024 |
| Adeptio Law Topco Limited | Financial services | 2024 |
| Aderoute Ltd | Transport & logistics | 2025 |
| Ades Divine Heritage Investments Limited | Wholesale & retail | 2023 |
| Ades-Devine Heritage Limited | Manufacturing | 2023 |
| Adesso Industrial Supplies Limited | Wholesale & retail | 2003 |
| Adey Medicals Ltd | Health & social care | 2025 |
| Adflow Solution Ltd | Wholesale & retail | 2024 |
| Adfm Inspire Limited | Administrative & support | 2025 |
| ADH Enterprising Limited | Wholesale & retail | 2016 |
| ADH Roofing and Cladding Consultancy and Management Ltd | Professional & scientific | 2018 |
| Adhana Private Ltd | Real estate | 2008 |
| Adhaunt Ltd | Transport & logistics | 2019 |
| ADI & JO Ltd | Transport & logistics | 2017 |
| ADI Eshi Investments Limited | Real estate | 2021 |
| ADI Technologies Ltd | Information & communication | 2022 |
| Adil Khalid Ltd | Education | 2026 |
| ADJ Holdings Limited | Health & social care | 2016 |
| ADL Bespoke Fire and Security Limited | Administrative & support | 2024 |
| ADL Bespoke Security Systems Limited | Administrative & support | 2019 |
| Adolog Solutions Ltd | Information & communication | 2023 |
| Adprik Services Ltd | Information & communication | 2022 |
| ADR Logistics Services Ltd | Transport & logistics | 2021 |
| Adrian Ashbrook Limited | Manufacturing | 2024 |
| Adrians Electrical Services Limited | Energy | 2015 |
| Adscarry Ltd | Wholesale & retail | 2024 |
| Adsma Ltd | Wholesale & retail | 2025 |
| Adult Newco Ltd | Financial services | 2024 |
| Advaita Domus Ltd | Real estate | 2018 |
| Advance Integrated Solutions Ltd | Administrative & support | 2023 |
| Advance Land & Planning Limited | Real estate | 2001 |
| Advanced Chemical Etching Limited | Manufacturing | 2000 |
| Advanced Coldformed Sections Ltd | Manufacturing | 2009 |
| Advanced Construction & Development Limited | Administrative & support | 2017 |
| Advanced Digital Services Limited | Information & communication | 2025 |
| Advanced Flooring Solutions Holdings Limited | Financial services | 2024 |
| Advanced Flooring Solutions Limited | Construction | 2011 |
| Advanced Group Limited | Financial services | 2018 |
| Advanced Primary Care Group Ltd | Administrative & support | 2017 |
| Advanced Resourcing Limited | Administrative & support | 2024 |
| Advancedscape Limited | Wholesale & retail | 2012 |
| Advancement Limited | Professional & scientific | 2015 |
| Advibe Studio Ltd | Wholesale & retail | 2025 |
| Advocates for International Development+ Limited | Transport & logistics | 2026 |
| AE Bhatia Ltd | Wholesale & retail | 2020 |
| AE Property Solutions Ltd | Real estate | 2019 |
| AE Real Estate Investment and Management Ltd | Real estate | 2017 |
| AE Solutions Services Limited | Health & social care | 2015 |
| AE110 Limited | Hospitality | 2021 |
| AE240 Limited | Hospitality | 2021 |
| AEB GAS Ltd | Construction | 2025 |
| AEE Healthcare Ltd | Health & social care | 2021 |
| Aegis Core AI Ltd | Information & communication | 2025 |
| Aelita Gold Ltd | Wholesale & retail | 2019 |
| AEM Oxford Limited | Administrative & support | 2025 |
| AEM Plumbing & Heating Services Limited | Construction | 2011 |
| Aequus Solicitors Ltd | Professional & scientific | 2020 |
| Aero AI Ltd | Information & communication | 2024 |
| Aero Consultants Ltd | Information & communication | 2011 |
| Aerojets Travel and Tours Ltd | Administrative & support | 2023 |
| Aeromight Ltd | Professional & scientific | 2016 |
| Aerotech Plus Limited | Professional & scientific | 2008 |
| Aesir Wealth Ltd | Financial services | 2016 |
| Aesora Limited | Financial services | 2024 |
| AET Cars Ltd | Wholesale & retail | 2024 |
| Aether Curios Ltd | Wholesale & retail | 2024 |
| Aether VOX Ltd | Information & communication | 2024 |
| AEU APT. Ltd | Construction | 2024 |
| AEW Services Limited | Real estate | 2011 |
| AF - Aviation Ltd | Transport & logistics | 2014 |
| AFC Birmingham Ltd | Arts & recreation | 2025 |
| AFC Wolverhampton CIC | Health & social care | 2024 |
| AFC Wolves CIC | Education | 2024 |
| AFC Wolves Group Ltd | Professional & scientific | 2026 |
| Affordable Building & Roofing Ltd | Other services | 2022 |
| Affordable Finance Limited | Financial services | 2007 |
| Affordable Fire Systems Ltd | Public administration | 2022 |
| Afghan Treasure Ltd | Wholesale & retail | 2025 |
| Afia's Food Limited | Manufacturing | 2012 |
| Afifi Medical Limited | Health & social care | 2015 |