| Adelma Ltd | Information & communication | 2026 |
| Adelphi (Kenyon Lane) Developments Limited | Real estate | 2018 |
| Aden Productions Limited | Information & communication | 1996 |
| Aden Stone Properties Ltd | Real estate | 2019 |
| Adenfox Limited | Health & social care | 2018 |
| Adenol Ltd | Financial services | 2025 |
| Adenview Limited | Health & social care | 2025 |
| Adeo Travel Ltd. | Administrative & support | 2012 |
| Adept Recovery Limited | Administrative & support | 2010 |
| Adepts Creative Industries Ltd | Information & communication | 2015 |
| Aderyn Building Consultancy Limited | Professional & scientific | 2014 |
| Aderyn Glas Ltd | Information & communication | 2019 |
| Adesaki Company Ltd | Other services | 2025 |
| Adesfort Limited | Professional & scientific | 2004 |
| Adesida Enterprise Limited | Financial services | 2014 |
| Adetom Limited | Administrative & support | 2025 |
| Adfeeder Ltd | Extraterritorial | 2016 |
| Adfer Environmental Limited | Professional & scientific | 2025 |
| ADG Enterprises Limited | Hospitality | 2019 |
| ADH Business Solutions Limited | Professional & scientific | 2014 |
| Adhal Ltd | Wholesale & retail | 2020 |
| Adhnan Ltd | Hospitality | 2025 |
| ADI Chiriac Ltd | Administrative & support | 2019 |
| Adidrops Ltd | Other services | 2025 |
| Adimac Ltd | Transport & logistics | 2015 |
| Adinkra Jackpot Ltd | Arts & recreation | 2025 |
| Adinne Ltd | Education | 2025 |
| Adinwest Europe Limited | Financial services | 2015 |
| Adipan Ltd | Hospitality | 2017 |
| Adipose Limited | Health & social care | 2010 |
| Adityaone Limited | Manufacturing | 2025 |
| Adjustment Digital Ltd | Other services | 2023 |
| Adkl Ltd | Wholesale & retail | 2026 |
| Adkshine Ltd | Wholesale & retail | 2025 |
| ADL Detailing Services Limited | Wholesale & retail | 2020 |
| ADL Transport and Logistics Limited | Transport & logistics | 2024 |
| Adlia Deli Ltd | Hospitality | 2023 |
| Adlon Iiix. Invest Limited | Administrative & support | 2010 |
| Adlr Training Ltd | Education | 2020 |
| ADM (U.K.) Limited | Manufacturing | 1994 |
| ADM Auto Group Ltd | Wholesale & retail | 2025 |
| ADM Local Ltd | Wholesale & retail | 2016 |
| ADM Number 1 Limited | Transport & logistics | 2016 |
| ADM UK Trading Limited | Wholesale & retail | 2014 |
| Admar Limited | Transport & logistics | 2012 |
| Admb 22 Ltd | Real estate | 2022 |
| Admc Consulting Group Ltd | Information & communication | 2020 |
| Admediawales Limited | Professional & scientific | 2021 |
| Admiral Financial Services Limited | Financial services | 2016 |
| Admiral Group PLC | Financial services | 1999 |
| Admiral Insurance Company Limited | Financial services | 2000 |
| Admiral Law Limited | Professional & scientific | 2012 |
| Admiral Roofing & Building Limited | Construction | 2025 |
| Admiral's Landing (Residents) Management Limited | Households | 1989 |
| Admirals Mead Ltd | Households | 2019 |
| Admire Florist Ltd | Wholesale & retail | 2014 |
| Admorphosis Ltd | Professional & scientific | 2025 |
| Adnan Impex Ltd | Wholesale & retail | 2024 |
| Adnan Trading Ltd | Wholesale & retail | 2017 |
| Adnewyddu CYF. | Real estate | 2016 |
| Adni Khan Ltd | Wholesale & retail | 2026 |
| Adnod CYF | Administrative & support | 2010 |
| Adnodd Cyfyngedig | Information & communication | 2022 |
| Adnova Solutions Ltd | Wholesale & retail | 2025 |
| Adofo Trading Ltd | Transport & logistics | 2019 |
| Adolad UK Ltd | Construction | 2016 |
| Adoncocar Ltd | Health & social care | 2023 |
| Adonia Maintenance Limited | Construction | 2026 |
| Adonis Entertainment Ltd | Wholesale & retail | 2018 |
| Adora Industry and Trade Ltd | Extraterritorial | 2016 |
| Adore London Limited | Real estate | 2015 |
| Adore Video Ltd | Information & communication | 2018 |
| ADP Europe Ltd | Administrative & support | 2012 |
| ADP Tiling Ltd | Construction | 2026 |
| Adrapana Limited | Professional & scientific | 2026 |
| Adref Ltd | Real estate | 2025 |
| Adrenalin Marketing Ltd | Professional & scientific | 2009 |
| Adrent Roofing Limited | Construction | 2025 |
| Adret Services Ltd | Real estate | 2023 |
| Adria Fiske Limited | Extraterritorial | 2025 |
| Adria SOL Ltd | Transport & logistics | 2018 |
| Adrian & Susan Lettings Ltd | Real estate | 2023 |
| Adrian Burrell Limited | Public administration | 2019 |
| Adrian C Dobre Limited | Transport & logistics | 2018 |
| Adrian Construction Ltd | Construction | 2013 |
| Adrian F1CNC Ltd | Manufacturing | 2026 |
| Adrian James Property Consultancy Limited | Real estate | 2012 |
| Adrian Mihai Stefan Limited | Construction | 2018 |
| Adrian Riley Building Services Limited | Construction | 2014 |
| Adriana Delle-Case Ltd | Professional & scientific | 2019 |
| Adrianpons Limited | Wholesale & retail | 2025 |
| Adriantransdelivery Ltd | Transport & logistics | 2019 |
| Adriatica Immobiliare Ltd | Wholesale & retail | 2014 |
| Adricomposit Limited | Manufacturing | 2025 |
| Adrihue Ltd | Wholesale & retail | 2025 |
| Adrimona Limited | Transport & logistics | 2019 |
| Adroit Security Services Limited | Wholesale & retail | 2014 |
| ADS & IT PC | | 2019 |
| ADS Capex Ltd | Hospitality | 2025 |
| ADS Media House Ltd | Information & communication | 2020 |