| ADD on IT Ltd | Information & communication | 2024 |
| Addboost Ltd | Professional & scientific | 2024 |
| Adde Properties Limited | Real estate | 2025 |
| Addeaze Company Ltd | Wholesale & retail | 2018 |
| Addlesee Timber & Haulage Ltd. | Wholesale & retail | 2001 |
| Addm Ltd | Health & social care | 2025 |
| Addonohue Ltd | Public administration | 2023 |
| Addu's Limited | Construction | 2021 |
| ADE B African Store Ltd | Wholesale & retail | 2025 |
| Adebe Transport Limited | Transport & logistics | 2023 |
| Adecam Ltd | Transport & logistics | 2022 |
| Adeco Group Ltd | Real estate | 2021 |
| Adecrown Ltd | Extraterritorial | 2022 |
| Adedoyin Oseni Ltd | Arts & recreation | 2024 |
| Adefey Group Ltd | Administrative & support | 2020 |
| Adefey Homes and Properties Ltd | Real estate | 2024 |
| Adelari Limited | Transport & logistics | 2024 |
| Ademedics Limited | Health & social care | 2023 |
| Adeways Limited | Hospitality | 2024 |
| ADF Trasport Ltd | Transport & logistics | 2019 |
| Adglobe Ltd. | Wholesale & retail | 2017 |
| ADH Home Improvement Ltd | Real estate | 2024 |
| ADH Surgical Ltd | Health & social care | 2022 |
| Adham Hotels Group Ltd | Hospitality | 2025 |
| Adhd & Autism Alliance Ltd | Health & social care | 2025 |
| ADI Car Detailing Ltd | Wholesale & retail | 2021 |
| ADI Swift Transport Ltd | Transport & logistics | 2025 |
| ADJ Petroleum & Construction Limited | Administrative & support | 2020 |
| ADJ Surfacing & Consultancy Limited | Professional & scientific | 2017 |
| Adlam Investments Ltd | Professional & scientific | 2017 |
| Adld Ltd. | Financial services | 2009 |
| Admat Ltd | Professional & scientific | 2019 |
| Admill Holdings Limited | Financial services | 2025 |
| Admill Storage Limited | Manufacturing | 2025 |
| Admill Storage Solutions Limited | Manufacturing | 2009 |
| Admincore Ltd | Administrative & support | 2025 |
| Administratiekantoor DE Graaf & Van Steeg LLP | | 2016 |
| Adonai Sports Management Ltd. | Financial services | 2025 |
| Adoniainternational Limited | Hospitality | 2023 |
| Adored Properties Ltd | Real estate | 2023 |
| ADP Business Solutions Ltd | Professional & scientific | 2014 |
| ADR Response Limited | Transport & logistics | 2022 |
| ADR Sheq Consultancy Ltd | Professional & scientific | 2014 |
| Adrean Ltd | Transport & logistics | 2020 |
| Adrian ISU Ltd | Transport & logistics | 2024 |
| Adrian Motors Ltd | Wholesale & retail | 2026 |
| Adrian Rosu Ltd | Transport & logistics | 2021 |
| Adrian Rotaru Ltd | Administrative & support | 2016 |
| Adrian W. Haulage Ltd | Transport & logistics | 2016 |
| Adrian Welch Glass & Glazing Limited | Construction | 2000 |
| Adrianis Ltd | Transport & logistics | 2018 |
| ADS Consultancy Ltd | Professional & scientific | 2024 |
| ADS Courier Services Ltd | Transport & logistics | 2020 |
| Adsum Services Limited | Other services | 2015 |
| ADT Joinery Ltd | Construction | 2011 |
| ADV Parts & Panels Ltd | Wholesale & retail | 2025 |
| Advance (Yorkshire) Limited | Administrative & support | 2000 |
| Advance Alarms & Security Limited | Construction | 2010 |
| Advance Commercial Finance (UK) Ltd | Financial services | 2023 |
| Advance Group UK Limited | Construction | 2009 |
| Advance IT Ltd | Information & communication | 2018 |
| Advance Mini Cabs Ltd | Transport & logistics | 2016 |
| Advanced 1 Roofing Ltd | Construction | 2025 |
| Advanced Auto Conversions Ltd | Manufacturing | 2022 |
| Advanced Autocare Limited | Wholesale & retail | 2007 |
| Advanced Caring (Doncaster) Limited | Health & social care | 2008 |
| Advanced Electro Ltd. | Administrative & support | 2003 |
| Advanced Engineering Workshops Ltd | Professional & scientific | 2023 |
| Advanced Holdings Limited | Professional & scientific | 2005 |
| Advanced HR Solutions Ltd | Administrative & support | 2010 |
| Advanced Rail Technologies Limited | Transport & logistics | 2004 |
| Advanced Scaffolding Solutions Limited | Construction | 2024 |
| Advanced Social Care Solutions Limited | Health & social care | 2024 |
| Advanced Treatments Ltd Ltd | Other services | 2022 |
| Advanced Tree Care Limited | Agriculture & fishing | 2001 |
| Advantage Coaching and Consulting Ltd | Professional & scientific | 2022 |
| Advantage Power Ltd | Real estate | 2022 |
| Adventuratech Ltd | Wholesale & retail | 2025 |
| Adventure Accessories Ltd | Wholesale & retail | 2025 |
| Adventure Investments Ltd | Real estate | 2024 |
| Adventure Vans Ltd | Administrative & support | 2021 |
| Adventures in Acting Ltd | Arts & recreation | 2024 |
| Adventuring Angels Ltd | Education | 2021 |
| ADVOCATE4SEN CIC | Education | 2025 |
| Adwick Aggregates Limited | Wholesale & retail | 2012 |
| Adwick Caravans Limited | Wholesale & retail | 2017 |
| Adwick Cleaning Services Ltd | Administrative & support | 2024 |
| Adwick Concrete Products Ltd | Manufacturing | 2021 |
| Adwick Scaffold Access Limited | Construction | 2019 |
| Ady&Tony Trans Ltd | Transport & logistics | 2023 |
| Adyalyluy Ltd | Wholesale & retail | 2025 |
| Adévara Limited | Real estate | 2025 |
| AE Ride Days Ltd | Arts & recreation | 2024 |
| AE Telco Ltd | Information & communication | 2022 |
| AE Valeting Ltd | Administrative & support | 2022 |
| AEA Packaging Limited | Wholesale & retail | 2013 |
| Aeden Consult Ltd | Professional & scientific | 2016 |
| Aedis CLT Ltd | Transport & logistics | 2015 |
| Aegir Consultancy Services Ltd | Other services | 2017 |
| AEH Properties Ltd | Real estate | 2021 |