| Adapt Properties (South West) Limited | Real estate | 2011 |
| Adapt Real Estate Limited | Real estate | 2018 |
| Adapt Senior Living Limited | Real estate | 2025 |
| Adaptavate Limited | Professional & scientific | 2014 |
| Adaptive Development Strategies Limited | Information & communication | 2014 |
| Adaptive Fitness Training Ltd | Education | 2025 |
| Adaptive Groundworks and Civils Ltd | Construction | 2026 |
| Adaptive Wellness Solutions Ltd | Information & communication | 2026 |
| Adaptogenic LAB Ltd | Wholesale & retail | 2023 |
| Adaptyle Limited | Information & communication | 2016 |
| Adar Transport Ltd | Manufacturing | 2018 |
| ADB Secure Electrical Services Ltd. | Professional & scientific | 2021 |
| Adbarke Limited | Construction | 2020 |
| Adbrain Limited | Information & communication | 2023 |
| ADC Plant Limited | Construction | 2016 |
| Addasu Engineering Ltd | Manufacturing | 2025 |
| Addiction Recovery Agency Limited | Health & social care | 1990 |
| Addison Ross (Holdings) Limited | Financial services | 2023 |
| Addison's Hair Ltd | Other services | 2023 |
| Additey Ltd | Wholesale & retail | 2024 |
| Addow Ltd | Hospitality | 2024 |
| Addpace Classics Limited | Wholesale & retail | 2019 |
| Addpace Limited | Real estate | 1997 |
| Addyman Electrical Limited | Construction | 2021 |
| ADE Cars Limited | Wholesale & retail | 2024 |
| ADE Electrical Services (Bristol) Limited | Construction | 2012 |
| Adebiopon Home Hero Ltd | Construction | 2026 |
| Adech Global Enterprises Limited | Information & communication | 2025 |
| Adeel's Grillz Ltd | Hospitality | 2025 |
| Adekanmbi Ltd | Health & social care | 2014 |
| Adekod Health Care Services Limited | Health & social care | 2016 |
| Adekunle Limited | Health & social care | 2025 |
| Adeleid LP | | 2014 |
| Adelina Yard Limited | Hospitality | 2015 |
| Ademi Contractors Ltd | Construction | 2022 |
| Adep Consulting Limited | Professional & scientific | 2025 |
| Adept Fire & Security Limited | Administrative & support | 2011 |
| Adept Fireplace Installations Ltd | Extraterritorial | 2008 |
| Adept Training Ltd | Education | 2018 |
| Adeptus Talent Limited | Administrative & support | 2024 |
| Adeshub Limited | Wholesale & retail | 2026 |
| Adeyemi Consultancy Ltd | Professional & scientific | 2020 |
| ADF Industries Limited | Real estate | 2014 |
| ADG Supplies Ltd | Wholesale & retail | 2024 |
| Adhara Solar Ltd | Energy | 2020 |
| Adhd Bristol Collective CIC | Education | 2026 |
| Adhd Clear Mind Coaching Limited | Health & social care | 2025 |
| Adhior Limited | Administrative & support | 1999 |
| Adhvik Limited | Health & social care | 2016 |
| ADI Driving Instructor Limited | Education | 2019 |
| ADI Trans International Ltd | Transport & logistics | 2017 |
| Adi-Pdi Tech Ltd | Information & communication | 2026 |
| Adieni Limited | Wholesale & retail | 2020 |
| Adieni Properties Limited | Real estate | 2023 |
| Adiflow Ltd | Wholesale & retail | 2025 |
| Adija Ltd | Other services | 2024 |
| Adika Group Ltd | Financial services | 2025 |
| Adina Maya Ltd | Wholesale & retail | 2018 |
| Adinijeconsultant Limited | Financial services | 2025 |
| Adiom Homes Ltd | Real estate | 2020 |
| Adistate Ltd | Construction | 2017 |
| Adivad Ltd | Transport & logistics | 2015 |
| Adixion Media Ltd | Information & communication | 2025 |
| ADJ Agencies Ltd | Wholesale & retail | 2012 |
| Adjacent Possible Limited | Information & communication | 2025 |
| Adjust Procurement Solutions Limited | Professional & scientific | 2003 |
| Adjust Your Crown Collection Ltd | Wholesale & retail | 2019 |
| Adjustabail Limited | Manufacturing | 2014 |
| Adking PLC | | 1990 |
| ADL Group Limited | Information & communication | 2017 |
| Adleadr Limited | Professional & scientific | 2017 |
| Adlib Trustees Limited | Administrative & support | 2020 |
| Adln Properties Ltd | Real estate | 2025 |
| Admenow Ltd | Professional & scientific | 2011 |
| Administrative and Support Services Limited | Administrative & support | 2005 |
| Admiral Energy Group Limited | | 1985 |
| Admiral Flooring Services Limited | Construction | 1998 |
| Admiral Harding Limited | Wholesale & retail | 2005 |
| Admiral Marine Limited | Financial services | 1991 |
| Admiral Marine Supplies Limited | Wholesale & retail | 1978 |
| Admiral Property Maintenance Limited | Construction | 2016 |
| Admiralty Court (Management) Limited | Real estate | 1992 |
| Admiralty Ship Models Ltd | Wholesale & retail | 2015 |
| Admor Mechanical Services Limited | Construction | 2012 |
| ADN Capital Markets Limited | Financial services | 2020 |
| ADN Drylining Ltd | Construction | 2017 |
| ADN Investment Products Limited | Financial services | 2020 |
| ADN Security Limited | Information & communication | 2025 |
| Adnaansales Ltd | Wholesale & retail | 2026 |
| Adnan Group Limited | Financial services | 2020 |
| Adnin Solutions Limited | Information & communication | 2022 |
| Adolescent Support Home Services Ltd | Hospitality | 2020 |
| Adonis Records Limited | Arts & recreation | 2019 |
| Adora Attack Ltd | Information & communication | 2021 |
| Adore Hair and Beauty Ltd | Other services | 2020 |
| Adore Hair Extensions Ltd | Other services | 2025 |
| Adoryn UK Ltd | Wholesale & retail | 2025 |
| ADP Finance and Advisory Services Limited | Professional & scientific | 2020 |
| Adpearce Ltd | Real estate | 2025 |
| Adpearl Enterprises Ltd | Professional & scientific | 2024 |