| Accpol Limited | Professional & scientific | 2011 |
| Accucomp Limited | Professional & scientific | 1985 |
| Accuma Financial Planning Limited | Financial services | 2016 |
| Accumulate Capital Limited | Professional & scientific | 2019 |
| Accumulate Commercial Limited | Professional & scientific | 2019 |
| Accumulate London SW Limited | Professional & scientific | 2019 |
| Accumulate NE Limited | Professional & scientific | 2020 |
| Accumulate Nominees Limited | Administrative & support | 2020 |
| Accumulate Residences Limited | Professional & scientific | 2019 |
| Accuratefx Ltd | Information & communication | 2023 |
| Accurex DRY Cleaners Limited | Other services | 2017 |
| Accuride International Limited | Wholesale & retail | 1939 |
| Acdc Ener-G Ltd | Construction | 2023 |
| Ace ADT Limited | Wholesale & retail | 2018 |
| Ace Aggregates Ltd | Wholesale & retail | 2023 |
| Ace Development Solutions Ltd | Construction | 2017 |
| Ace Gearboxes Ltd. | Wholesale & retail | 1981 |
| Ace Lincs Logistics Boston Ltd | Transport & logistics | 2019 |
| Ace Lincs Logistics Ltd | Transport & logistics | 2019 |
| Ace of Fadez Barbers Ltd | Other services | 2018 |
| Ace Removals (Northamptonshire) Ltd | Transport & logistics | 2015 |
| Ace Services & Commercial Repairs Limited | Manufacturing | 2024 |
| Ace Systems Training Ltd | Administrative & support | 2014 |
| Ace Windows Ltd | Construction | 2011 |
| Aceed Property Management Limited | Real estate | 2024 |
| Acegate Ltd | Administrative & support | 2016 |
| Acem Community Limited | Wholesale & retail | 2026 |
| Acepower Consultancy Ltd | Professional & scientific | 1998 |
| Acer Engineering (Bedford) Limited | Manufacturing | 2000 |
| Achava Ltd | Professional & scientific | 2024 |
| Achfuse Limited | Information & communication | 2015 |
| Achiarya Limited | Professional & scientific | 2024 |
| Achieve Excellence Limited | Education | 2007 |
| Acilisav Uivil Ltd | Transport & logistics | 2023 |
| Ackon Convenience Store Ltd | Wholesale & retail | 2024 |
| Ackraceeproofreading Ltd | Professional & scientific | 2025 |
| Ackrack Pencil Limited | Real estate | 1994 |
| Aclasscs Ltd | Administrative & support | 2023 |
| Aclo Food Ltd | Transport & logistics | 2020 |
| ACM Property Care Ltd | Construction | 2022 |
| Acme Property Management Ltd | Extraterritorial | 2015 |
| ACO Security Limited | Administrative & support | 2013 |
| Acordd Doors Limited | Construction | 2005 |
| Acorn Analytical Services (UK) Ltd | Professional & scientific | 2012 |
| Acorn Business Holdings Ltd | Administrative & support | 2022 |
| Acorn Childcare (UK) | Education | 2001 |
| Acorn Children's Home (Branston) Ltd | Health & social care | 2016 |
| Acorn Commercial Finance Ltd | Financial services | 2020 |
| Acorn Commercial Loans Limited | Financial services | 2021 |
| Acorn Paragon Ltd | Transport & logistics | 2022 |
| Acorn Safety Services Ltd | Professional & scientific | 2020 |
| Acornbrook Forwarding Ltd | Transport & logistics | 2019 |
| Acorndrift Limited | Education | 2001 |
| Acorndrive Limited | Education | 2001 |
| Acorns Management Company (1988) Limited | Administrative & support | 1988 |
| ACP Formwork Ltd | Construction | 2020 |
| ACP Property Development Limited | Construction | 2016 |
| ACP Transport Ltd | Transport & logistics | 2023 |
| Acquisition Wealth Management Limited | Financial services | 2017 |
| ACR Carpets Ltd | Construction | 2015 |
| Acre Contracting Limited | Construction | 2006 |
| Acre Court Management Limited | Households | 1992 |
| Acre Property Ltd | Real estate | 2014 |
| Acrity Investments Limited | Financial services | 2023 |
| Acro Holdings Limited | Professional & scientific | 2017 |
| Acrossbay Pure & Co. Ltd | Wholesale & retail | 2025 |
| Acrylic Design Watford Limited | Manufacturing | 2018 |
| Acrylic Sports Coatings Ltd | Arts & recreation | 2010 |
| ACS Office Solutions Limited | Wholesale & retail | 1997 |
| ACS Recruitment Limited | Extraterritorial | 2026 |
| ACS Recruitment Solutions Limited | Administrative & support | 2015 |
| ACS Services Ltd | Construction | 2026 |
| ACS Staffing Solutions Limited | Extraterritorial | 2023 |
| ACS Systems UK Limited | Wholesale & retail | 1994 |
| ACT Awareness Limited | Information & communication | 2024 |
| ACT Investment Northants Limited | Real estate | 2017 |
| ACT Professionals Limited | Professional & scientific | 2025 |
| Action Apparel Limited | Wholesale & retail | 2025 |
| Action Argyll Limited | Professional & scientific | 2019 |
| Activate B. D. Limited | Other services | 2009 |
| Activate Business Finance Limited | Financial services | 2023 |
| Activate Lead Generator Ltd | Administrative & support | 2016 |
| Activbyaustin Ltd | Arts & recreation | 2024 |
| Active 5 Limited | Construction | 2013 |
| Active Ants UK Ltd | Transport & logistics | 2021 |
| Active Cleaning & Maintenance (Midlands) Limited | Administrative & support | 2010 |
| Active CUT Ltd | Construction | 2024 |
| Active Networx Limited | Information & communication | 2016 |
| Active Recruitment Limited | Administrative & support | 2009 |
| Active Scenery Ltd | Manufacturing | 2026 |
| Active Taxis North Ltd | Transport & logistics | 2019 |
| ACTIVE8 Learning Ltd | Education | 2023 |
| Actnow Consulting Ltd | Professional & scientific | 2023 |
| Actuality Plus Limited | Professional & scientific | 2001 |
| Acuda Ltd | Information & communication | 2021 |
| Acuity Growth Consultancy Ltd | Professional & scientific | 2021 |
| Aculogic Limited | Information & communication | 2025 |
| Acumen Business Development Ltd | Real estate | 2012 |
| Acumen Marketing Services Limited | Professional & scientific | 1999 |
| Acumen Trading Limited | Wholesale & retail | 2006 |