| Ace Mobile Detailing Limited | Manufacturing | 2021 |
| Ace Prestige Driving School Ltd | Education | 2024 |
| Ace Tax Solutions Ltd | Administrative & support | 2026 |
| Ace Transfers Limited | Transport & logistics | 2022 |
| Acebruk Associacao Comercial E Empresarial Para Brasileiros NO Reino Unido Limited | Other services | 2025 |
| Acee Ltd | Professional & scientific | 2024 |
| Acell Solutions UK Limited | Wholesale & retail | 2013 |
| Aceport Property Ltd | Construction | 2001 |
| Acer Asset Investments Limited | Real estate | 2020 |
| Acer Holdings Group Limited | Financial services | 2020 |
| Acer Lets Limited | Hospitality | 2023 |
| Acer Renovations Ltd | Construction | 2011 |
| Aces Indoor Golf Ltd | Arts & recreation | 2022 |
| Acgreg-Trans Ltd | Transport & logistics | 2023 |
| Achenbach PUB Co Ltd | Hospitality | 2019 |
| Achieve Aesthetics Limited | Health & social care | 2023 |
| Achieve Care Ltd | Health & social care | 2020 |
| Achilles Investments Limited | Construction | 1972 |
| Aciv Limited | Transport & logistics | 2024 |
| ACJ Cranes Limited | Administrative & support | 2019 |
| ACJ Glazing Solutions Limited | Construction | 2011 |
| ACJ Plant Hire Limited | Administrative & support | 2021 |
| ACK Marine Ltd | Professional & scientific | 2026 |
| ACM Architects Limited | Professional & scientific | 2020 |
| ACM Costa Logistics Ltd | Transport & logistics | 2026 |
| ACM Euro Ltd | Professional & scientific | 2020 |
| ACM TM Ltd | Transport & logistics | 2023 |
| Acme Marine Electrical Ltd | Construction | 2026 |
| Acme Shipping & Logistics (UK) Limited | Transport & logistics | 2008 |
| Acme Stunts Inc Ltd | Information & communication | 2018 |
| Acneil Ltd | Administrative & support | 2012 |
| Acockscatering Limited | Hospitality | 2026 |
| Acol Cleaning & Hygiene Limited | Administrative & support | 1994 |
| Acol Group Limited | Administrative & support | 2019 |
| Acons International Educational Consultancy Ltd | Other services | 2025 |
| Acor Limited | Health & social care | 2023 |
| Acorn & Growan Ltd | Agriculture & fishing | 2024 |
| Acorn Alloy Repairs Ltd | Wholesale & retail | 2012 |
| Acorn Building Contracts Limited | Construction | 2005 |
| Acorn Gardening and Landscaping Ltd | Administrative & support | 2021 |
| Acorn Property Management Services Limited | Real estate | 1999 |
| Acorn Tree Specialist Limited | Agriculture & fishing | 2016 |
| Acorns (Southern) Bidco Limited | Financial services | 2024 |
| Acorns (Southern) Holdings Limited | Financial services | 2024 |
| Acorns (Southern) Leaseco Limited | Real estate | 2025 |
| Acorns (Southern) Limited | Administrative & support | 2019 |
| Acorns Community Pre-School Limited | Education | 2007 |
| Acovelli Ltd | Manufacturing | 2022 |
| ACQ Locksmiths Ltd | Administrative & support | 2009 |
| Acrana Limited | Real estate | 2017 |
| Acrobat Promotions Limited | Wholesale & retail | 2004 |
| Across the Market Mortgages Limited | Financial services | 2019 |
| Acrz Limited | Hospitality | 2026 |
| ACT Seven Technology Limited | Information & communication | 2008 |
| ACT TOO Limited | Education | 2003 |
| Actimize UK Limited | Information & communication | 2004 |
| Action Tax Consulting Limited | Administrative & support | 2008 |
| ACTION24 Healthcare Ltd | Health & social care | 2023 |
| Actipaws Limited | Agriculture & fishing | 2024 |
| Active Alchemy Ltd | Wholesale & retail | 2023 |
| Active Group Commercial Co. Limited | Wholesale & retail | 2025 |
| Active Linkers Ltd | Information & communication | 2024 |
| Active Powwr Ltd | Energy | 2024 |
| Activiccii Ltd | Wholesale & retail | 2026 |
| Actual Reality Limited | Manufacturing | 2026 |
| Acufireuk Ltd | Professional & scientific | 2013 |
| Aculeus Ltd | Information & communication | 2009 |
| Acupuncture China Limited | Health & social care | 2017 |
| Acus Developments Ltd | Construction | 2024 |
| Acute Look Limited | Other services | 2007 |
| Acute Removals Limited | Transport & logistics | 2023 |
| ACW Monarch Properties Ltd | Real estate | 2026 |
| AD (Southern) Fire Limited | Public administration | 2025 |
| AD Altiora Ltd | Real estate | 2024 |
| AD Apartments Ltd | Real estate | 2021 |
| AD King Consultancy Limited | Professional & scientific | 2025 |
| AD King Investments Limited | Real estate | 2024 |
| ADA Mode Limited | Professional & scientific | 2019 |
| Adalec Electrical Contractors Ltd | Construction | 2013 |
| Adam Gibson Treecare Specialist Limited | Administrative & support | 2017 |
| Adam Hand Car Valeting Ltd | Administrative & support | 2024 |
| Adam Harnett Golf Ltd | Education | 2025 |
| Adam Hawley Limited | Health & social care | 2019 |
| Adam Klos Painter and Decorator Ltd | Construction | 2025 |
| Adam Zielinski Construction Ltd | Construction | 2017 |
| Adamgray Financial Services Ltd | Professional & scientific | 2009 |
| Adams & Barford Ltd | Construction | 2018 |
| Adams & Gibbon Limited | Real estate | 1986 |
| Adams Precision Hydraulics Limited | Professional & scientific | 2020 |
| Adams-Morey Limited | Wholesale & retail | 1952 |
| Adamtf Sounds Ltd | Wholesale & retail | 2025 |
| Adanac Business Park Limited | Construction | 2017 |
| Adanac Developments Limited | Construction | 2024 |
| Adanac Gateway Limited | Construction | 2016 |
| Adanac North Property Management Company Limited | Real estate | 2008 |
| Adanac Technologies Limited | Manufacturing | 2026 |
| Adapt 2 Ltd | Construction | 2022 |
| Adapt Hospitality Limited | Hospitality | 2025 |
| Adapt Mgmt Limited | Professional & scientific | 2024 |
| Adaptations Plus Ltd | Administrative & support | 2023 |