| Accounts Action Limited | Professional & scientific | 2010 |
| ACD Investments Ltd | Real estate | 2023 |
| Ace Trainers Ltd | Wholesale & retail | 2012 |
| Acestars Limited | Arts & recreation | 2002 |
| ACF Creative Ltd | Professional & scientific | 2019 |
| Achieving Solutions Limited | Arts & recreation | 2005 |
| Acla Trading Ltd | Professional & scientific | 2024 |
| ACM Innovations Limited | Information & communication | 2011 |
| ACM Roofing Ltd | Construction | 2022 |
| Acmbeng Communicare Limited | Professional & scientific | 2025 |
| Acorn Property Investments 2020 Ltd | Real estate | 2021 |
| Acorn Property Partnership LLP | | 2021 |
| Acorn Property Refurbishments Ltd | Construction | 2009 |
| ACR Bidco Limited | Manufacturing | 2025 |
| Acrid Studio Ltd | Information & communication | 2025 |
| Acrospire Holdings Limited | Professional & scientific | 2020 |
| Acrospire Products Limited | Manufacturing | 2017 |
| Acrospire Solutions Limited | Manufacturing | 2012 |
| Action and Theory Ltd | Professional & scientific | 2011 |
| Action Trophies Limited | Wholesale & retail | 2003 |
| Active Informatics Ltd | Information & communication | 2008 |
| Active Smile Ltd | Health & social care | 2012 |
| Acuity Learning Academy Ltd | Education | 2023 |
| Acumak Ltd | Manufacturing | 2007 |
| AD Engitech Limited | Extraterritorial | 2023 |
| AD Inovest Limited | Professional & scientific | 2023 |
| AD Leading Limited | Manufacturing | 2021 |
| AD Lettings Limited | Extraterritorial | 2024 |
| AD Libertas Limited | Wholesale & retail | 2017 |
| AD Real Asset Ltd | Real estate | 2023 |
| AD Resort Ltd | Transport & logistics | 2018 |
| AD Spectrum Limited | Professional & scientific | 2023 |
| Ad-Libertas Publishing Limited | Wholesale & retail | 2017 |
| ADA Property Limited | Real estate | 2021 |
| Adam Continuity Limited | Information & communication | 2003 |
| Adam's Decorating Solutions Ltd | Construction | 2026 |
| Adamantean Asset Finance Limited | Financial services | 2021 |
| Adamantean Consulting Limited | Financial services | 2018 |
| Adamantean Limited | Financial services | 2016 |
| Adaptive Comforts Care UK Ltd | Health & social care | 2023 |
| ADC Logistik Ltd | Transport & logistics | 2016 |
| ADD Graphene Group Limited | Professional & scientific | 2024 |
| Addepar UK Ltd. | Information & communication | 2021 |
| Addvoice Limited | Information & communication | 2019 |
| Adeni Consultancy Limited | Information & communication | 2014 |
| ADI Technology Limited | Information & communication | 2013 |
| Adjara Limited | Health & social care | 2018 |
| ADL (Vantage House) Ltd | Real estate | 2019 |
| Adm&F Limited | Professional & scientific | 2024 |
| Admeter Limited | Information & communication | 2005 |
| Adminworks Ltd | Administrative & support | 2009 |
| Admr Property Services Ltd | Administrative & support | 2023 |
| Adnantaj Ltd | Wholesale & retail | 2024 |
| Adrian CHR Ltd | Transport & logistics | 2020 |
| Adriza London Ltd | Manufacturing | 2018 |
| Adsphere Digital Limited | Professional & scientific | 2026 |
| Adsync Ltd | Information & communication | 2024 |
| Adtran Europe Limited | Wholesale & retail | 2004 |
| Advaith IT Solutions Ltd | Information & communication | 2025 |
| Advance Throwing Mills Limited | | 1964 |
| Advanced Auto Tech Services Ltd | Wholesale & retail | 2020 |
| Advanced Broadcast Integration Ltd | Information & communication | 2012 |
| Advanced Spirituality Ltd | Information & communication | 2008 |
| Advanced Technology Trading Company Ltd | Professional & scientific | 2016 |
| Advantedge Agency Ltd | Professional & scientific | 2015 |
| Advitek Solutions Ltd | Information & communication | 2018 |
| ADW Safety Cloud Limited | Professional & scientific | 2016 |
| AE Accounting Ltd | Professional & scientific | 2017 |
| AE Social Care and Education Limited | Health & social care | 2014 |
| Aegis Properties Ltd | Real estate | 2020 |
| AEJ Limited | Real estate | 2024 |
| Aeonium Consulting Limited | Information & communication | 2017 |
| Aero Trade Solutions Limited | Wholesale & retail | 2026 |
| AES Metals Ltd | Wholesale & retail | 2014 |
| Aesthetic Training and Consulting Ltd | Education | 2024 |
| Aether Core Ltd | Manufacturing | 2026 |
| AFE Asset Solutions Limited | Financial services | 2020 |
| Affinity Creations Ltd | Manufacturing | 2024 |
| Afriwood UK Ltd | Wholesale & retail | 2020 |
| Afrizi Limited | Hospitality | 2021 |
| AFS Aviation Limited | Manufacturing | 2012 |
| AFT Transport Ltd | Transport & logistics | 2019 |
| AG Barber Services Ltd | Other services | 2021 |
| AG Consulting & Services Limited | Administrative & support | 2023 |
| Agastya Software Solutions Ltd | Information & communication | 2011 |
| AGB Automation Ltd | Construction | 2010 |
| AGD Logistics 24/7 Ltd | Transport & logistics | 2021 |
| AGI Professionals Ltd | Extraterritorial | 2014 |
| AGI Properties SPV Ltd | Real estate | 2024 |
| AGL Fence Contractors Ltd | Manufacturing | 2020 |
| AGM Consulting and Development Ltd | Construction | 2017 |
| Agni SP Ltd | Wholesale & retail | 2022 |
| AGO Consulting Limited | Professional & scientific | 2019 |
| Agranergy UK Limited | Professional & scientific | 2025 |
| Agreda Improvement and Maintenance Limited | Construction | 2025 |
| Agronomy Buying Services Limited | Agriculture & fishing | 2000 |
| AHS Environmental Ltd | Professional & scientific | 2025 |
| Ahuja & Family Ltd | Wholesale & retail | 2024 |
| AI Estate Group Ltd | Construction | 2023 |
| AI Mechanic Ltd | Wholesale & retail | 2026 |