| Addan Limited | Information & communication | 2005 |
| Addington Close Management Limited | Households | 2024 |
| Addington Estates Limited | Real estate | 2005 |
| Addisons Healthcare Ltd | Health & social care | 2022 |
| Addistech Limited | Real estate | 2015 |
| ADE Mcadio Limited | Information & communication | 2013 |
| Adeel Ltd | Real estate | 2020 |
| Adejamo Holdings Ltd | Arts & recreation | 2024 |
| Adek Solutions Ltd | Information & communication | 2023 |
| Adelc Property Limited | Real estate | 2025 |
| Adele Consulting Limited | Other services | 2016 |
| Adelphi Estates Limited | Construction | 1998 |
| Adept Coding Limited | Information & communication | 2018 |
| Adept Locums Limited | Health & social care | 2008 |
| Adept Medical Limited | Health & social care | 2021 |
| Adept Medical Solutions Limited | Health & social care | 2010 |
| Adept Supply Limited | Wholesale & retail | 2008 |
| Adept Transcription Limited | Administrative & support | 2003 |
| Adepteq Ltd | Professional & scientific | 2006 |
| Adepto Consulting Limited | Administrative & support | 2013 |
| Adeq Ltd | Construction | 2014 |
| Adesquare Healthcare Ltd | Public administration | 2022 |
| Adesuwa Omoregie Ogie. AOO Childcare Services Ltd | Health & social care | 2026 |
| ADF Tech Ltd | Information & communication | 2016 |
| ADF Trueway Ltd | Wholesale & retail | 2020 |
| Adfest International Limited | Professional & scientific | 2021 |
| ADG Logistics Ltd | Transport & logistics | 2024 |
| Adhesive Dispensing Limited | Wholesale & retail | 2007 |
| Adhi Solutions Limited | Information & communication | 2008 |
| Adhyayanam Ltd | Arts & recreation | 2023 |
| ADI Constructions & Maintenance Limited | Construction | 2020 |
| ADI Sivalingam Legal Consultant Limited | Professional & scientific | 2013 |
| Adi's Coffee Beans Limited | Manufacturing | 2025 |
| Adi's Plumbing+ Ltd | Construction | 2023 |
| Adi.I.L.A.Com Ltd | Information & communication | 2023 |
| Adia Estate Agents Limited | Real estate | 2025 |
| Adicoco Ltd | Transport & logistics | 2018 |
| Adikctd Ltd | Manufacturing | 2022 |
| Adimbola Limited | Hospitality | 2018 |
| ADJ Autos Ltd | Wholesale & retail | 2024 |
| Adjust to Health Limited | Health & social care | 2004 |
| Adjust to Properties Ltd | Real estate | 2021 |
| Adkins Renovations Ltd | Construction | 2020 |
| ADL Dermatology Ltd | Health & social care | 2020 |
| ADL Developments Limited | Construction | 2016 |
| ADL Waste Removal Limited | Water & waste | 2026 |
| Adlc Properties Ltd | Real estate | 2022 |
| ADM Financials Ltd | Information & communication | 2024 |
| ADM Haulage Ltd | Wholesale & retail | 2022 |
| Adminday Ltd | Administrative & support | 2025 |
| Admiral Airport Taxis Ltd | Transport & logistics | 2014 |
| Admiral Property Investments Limited | Other services | 2011 |
| Admj Services Ltd | Wholesale & retail | 2025 |
| Admk Electrical Ltd | Construction | 2025 |
| Admk Limited | Construction | 2017 |
| ADN Excavations Ltd | Construction | 2021 |
| Adnan Medical Services Ltd | Health & social care | 2011 |
| Adnauseam Ltd | Information & communication | 2023 |
| Adorable Lifestyle Limited | Wholesale & retail | 2020 |
| Adoring Care Ltd | Health & social care | 2022 |
| Adorn Atelier Ltd | Wholesale & retail | 2023 |
| ADP Analytics Limited | Information & communication | 2020 |
| Adqura Holdings Ltd | Information & communication | 2023 |
| Adqura Limited | Information & communication | 2011 |
| Adreco Limited | Manufacturing | 1977 |
| Adri Homes Limited | Real estate | 2024 |
| Adrian Garstang Limited | Financial services | 2008 |
| Adrian Harris Limited | Construction | 2003 |
| Adrian Russell Limited | Information & communication | 2015 |
| Adrian Tamas Limited | Transport & logistics | 2021 |
| Adrian Todirica 5580 Ltd | Construction | 2016 |
| Adrian Wise Blinds Limited | Manufacturing | 2024 |
| Adriana Cojocaru Ltd | Other services | 2021 |
| Adriana's Bridal Ltd | Manufacturing | 2020 |
| Adroit Consultation 2 Limited | Professional & scientific | 2012 |
| Adroit Window Systems Ltd | Manufacturing | 2023 |
| ADS and Jojo Limited | Information & communication | 2015 |
| Adsmartway Ltd. | Information & communication | 2013 |
| Adstarplus Ltd | Information & communication | 2021 |
| Adstock Building Services Limited | Construction | 2015 |
| Adstock PUB Company Ltd | Hospitality | 2023 |
| Adsyncro Ltd | Professional & scientific | 2025 |
| ADT Consulting Limited | Professional & scientific | 2023 |
| ADT Technologies Ltd | Information & communication | 2019 |
| Adullam(Tsp) Ltd | Real estate | 2024 |
| Advance Aesthetics Ltd | Health & social care | 2014 |
| Advance Projects T/A APL Refurbishments Ltd | Other services | 2019 |
| Advance Property Limited | Real estate | 2015 |
| Advance Real Estates Ltd | Real estate | 2021 |
| Advance Travel Limited | Administrative & support | 2004 |
| Advanced African Associates Ltd | Professional & scientific | 2023 |
| Advanced Automation Solutions Limited | Manufacturing | 2001 |
| Advanced Cardiovascular Care Ltd | Health & social care | 2024 |
| Advanced Commerce Solutions Ltd | Wholesale & retail | 2019 |
| Advanced Cybercrafts Ltd | Information & communication | 2022 |
| Advanced Earth Metals Ltd | Mining & quarrying | 2020 |
| Advanced Plastic Technology Limited | Manufacturing | 1991 |
| Advanced Robotics Limited | Manufacturing | 2003 |
| Advanced Screen Technology Limited | Manufacturing | 2002 |
| Advanced Traffic Services Limited | Administrative & support | 2019 |