| Adalsha Foods Limited | Hospitality | 2024 |
| Adam Andrusier Autographs Ltd | Arts & recreation | 2011 |
| Adam Andrusier Writing Ltd | Information & communication | 2020 |
| Adam Cuadra Ltd | Other services | 2024 |
| Adam Dare Ltd | Information & communication | 2011 |
| Adam Dawe Design Limited | Professional & scientific | 2007 |
| Adam Elite Construction Ltd | Construction | 2025 |
| Adam Foundation | Other services | 2024 |
| Adam Housing UK Ltd | Construction | 2024 |
| Adam James Funeral Service Limited | Other services | 2011 |
| Adam Lemon Training Limited | Other services | 2012 |
| Adam Lovelock Entertainment Ltd | Information & communication | 2024 |
| Adam Property Services.London Limited | Real estate | 2018 |
| Adam Sadar & Co Estates Ltd | Real estate | 2024 |
| Adam Swift Logistics Ltd | Transport & logistics | 2026 |
| Adam Ventilation & Coldroom Ltd | Manufacturing | 2020 |
| Adamanr Ltd | Hospitality | 2026 |
| Adamapp Ltd | Information & communication | 2017 |
| Adamo Corp Ltd | Hospitality | 2024 |
| Adamo Estates Limited | Real estate | 2014 |
| Adams Food Global Ltd. | Administrative & support | 2019 |
| Adams Gold Limited | Manufacturing | 1996 |
| Adams Green Limited | Hospitality | 2017 |
| Adams Media Work Ltd | Information & communication | 2011 |
| Adams Removals Ltd | Transport & logistics | 2005 |
| Adam’S Coffe on the Wheels Limited | Manufacturing | 2023 |
| Adan Corporate Services Limited | Professional & scientific | 2013 |
| Adaptainer Limited | Transport & logistics | 1989 |
| Adarsak Ltd | Education | 2024 |
| Adblogistics Limited | Transport & logistics | 2025 |
| ADC Technology Training Limited | Information & communication | 1998 |
| Adcaav Properties Ltd | Construction | 2025 |
| Adclaas Media Limited | Professional & scientific | 2026 |
| Adcult Ltd | Professional & scientific | 2026 |
| ADD 2 Property Developments LLP | | 2021 |
| ADD Concept Ltd | Construction | 2017 |
| ADD Property Value Limited | Real estate | 2020 |
| Addb Limited | Health & social care | 2021 |
| Addington Cole Group Ltd | Financial services | 2020 |
| Addition Investments Limited | Real estate | 2025 |
| Addmargin Limited | Households | 1988 |
| Addstone Investment Ltd | Real estate | 2010 |
| Addurra Ltd | Other services | 2013 |
| ADE Press Ltd | Professional & scientific | 1996 |
| Adedge Ltd | Education | 2025 |
| Adelaide Children's Physio Ltd | Health & social care | 2016 |
| Adelaide Properties Limited | Households | 2011 |
| Adelina Dreams Limited | Administrative & support | 2022 |
| Aden Consultants Ltd | Professional & scientific | 1997 |
| ADF Foods UK Limited | Wholesale & retail | 2002 |
| Adhi Ltd | Professional & scientific | 2009 |
| Adhicine Solutions Ltd | Information & communication | 2024 |
| Adhirat Chemicals & Minerals Limited | Wholesale & retail | 2022 |
| Adhoc Limited | Construction | 2018 |
| Adhya Shakti Newsagent Limited | Wholesale & retail | 2020 |
| ADI Racing Ltd | Arts & recreation | 2022 |
| Adispan UK Ltd | Administrative & support | 2025 |
| Aditya Manojkumar Limited | Wholesale & retail | 2025 |
| ADL 1 Ltd | Health & social care | 2021 |
| Adlam Consulting Limited | Administrative & support | 1999 |
| Adlers Surveyors Consulting Limited | Construction | 2012 |
| Adlers Surveyors LLP | | 2012 |
| Adlevo Aeternum Limited | Financial services | 2024 |
| ADM Building Solutions Ltd | Construction | 2024 |
| ADM Hospitality Ventures Ltd | Hospitality | 2024 |
| Admiral (London) Limited | Wholesale & retail | 2008 |
| Admire Events and Decor Limited | Hospitality | 2024 |
| Adne Properties Limited | Construction | 2000 |
| Adnk Properties Ltd | Real estate | 2024 |
| Adoc Limited | Health & social care | 2015 |
| Adoeva Associates (UK) Ltd | Professional & scientific | 2025 |
| Adonis Freight Services Ltd | Transport & logistics | 2018 |
| Adonis Multi Service Ltd | Construction | 2025 |
| Adoptplan Properties Limited | Real estate | 1983 |
| Adora Financial Services Limited | Financial services | 2006 |
| Adorai Limited | Wholesale & retail | 2024 |
| Adore Jewlery Limited | Manufacturing | 2024 |
| Adoria Limited | Construction | 2010 |
| Adorn Beauty and Care Ltd | Other services | 2010 |
| Adorn Jewellary Ltd | Wholesale & retail | 2025 |
| Adorn Trade Ltd | Wholesale & retail | 2016 |
| Adorne Window Cleaning Limited | Administrative & support | 2025 |
| Adrenaline Studios / Voicearchive UK Ltd. | Information & communication | 2016 |
| Adrigole Properties Limited | Real estate | 2001 |
| Adrija Ltd | Wholesale & retail | 2024 |
| Adroit Bespoke Ltd | Construction | 2023 |
| Adroit Bros Ltd | Construction | 2019 |
| Adroit Brothers Contractors Ltd | Construction | 2017 |
| Adroit Business Consulting Ltd | Information & communication | 2011 |
| Adroit Homes Ltd | Real estate | 2020 |
| Adroit People Ltd | Information & communication | 2007 |
| Adrongems Ltd | Wholesale & retail | 2025 |
| Adryano Construction Ltd | Construction | 2017 |
| ADS Developers Ltd | Real estate | 2020 |
| ADSS15 Limited | Transport & logistics | 2018 |
| Adswise Ltd | Professional & scientific | 2025 |
| Adukalam Property Investment Ltd | Real estate | 2024 |
| Adultino Healthcare Limited | Health & social care | 2023 |
| Advait Enterprises Ltd | Wholesale & retail | 2024 |
| Advance Enginering Solutions Limited | Wholesale & retail | 2019 |