| Ace Electricians Limited | Construction | 2017 |
| Ace Equity Holdings Ltd | Real estate | 2026 |
| Ace Financial Consultancy Ltd | Professional & scientific | 2024 |
| Ace Financial Services Limited | Professional & scientific | 2023 |
| Ace Fitter Services Ltd | Administrative & support | 2024 |
| Ace Homecare Services Limited | Real estate | 2016 |
| Ace Inventory Management Limited | Information & communication | 2021 |
| Ace of Spades Landscaping and Garden Maintenance Limited | Wholesale & retail | 2020 |
| Ace Rental Homes Ltd | Households | 2024 |
| Ace Restaurant Tech Ltd | Information & communication | 2016 |
| Ace Rubber Products Ltd | Manufacturing | 2012 |
| Ace Signage Limited | Administrative & support | 2022 |
| Ace UK Accountancy Services Limited | Professional & scientific | 2024 |
| Acefix Property Services Ltd | Construction | 2026 |
| Aceleaf Limited | Information & communication | 2000 |
| Acemate Ltd | Professional & scientific | 1996 |
| Acemaximus Limited | Professional & scientific | 2017 |
| Acer Properties (Burnham) Limited | Construction | 2016 |
| Acescore Limited | Financial services | 2024 |
| Aceserve Ltd | Wholesale & retail | 2024 |
| Acesso Innovation LAB Limited | Health & social care | 2023 |
| Acestar Care Ltd | Health & social care | 2018 |
| ACG Construction Services Ltd | Construction | 2020 |
| ACH Project Management Limited | Construction | 2017 |
| Achieva Investments Limited | Administrative & support | 2022 |
| Achieva Limited | Administrative & support | 2021 |
| Achieva Properties Limited | Real estate | 2022 |
| Achieve Dreams Limited | Other services | 2025 |
| Achieve Learning | Education | 2007 |
| Achieve Learning Centres Limited | Information & communication | 2004 |
| Achille Productions (Falling) Limited | Information & communication | 2019 |
| Achl Services Ltd | Wholesale & retail | 2017 |
| ACI Properties Limited | Construction | 2014 |
| Acintya (GB) Limited | Construction | 2010 |
| Ackme Ltd | Transport & logistics | 2013 |
| ACM Psychology Ltd | Education | 2019 |
| Acme Properties (UK) Ltd | Real estate | 2006 |
| Acme Property Harrow Ltd | Construction | 2025 |
| Acorn (Harrow) Limited | Administrative & support | 2025 |
| Acorn Care Centres Limited | Real estate | 2000 |
| Acorn Engraving Co. Ltd | Other services | 2002 |
| Acorns Lodge Hotel Limited | Hospitality | 2004 |
| Acornville Limited | Real estate | 2011 |
| Acpz Consultancy Ltd | Wholesale & retail | 2025 |
| Acqua Plus Developments Limited | Construction | 2003 |
| Acquire X Consulting Limited | Professional & scientific | 2023 |
| ACR Property Management Limited | Real estate | 2024 |
| Acre 1220 Limited | Financial services | 2019 |
| Acre 714 Limited | Wholesale & retail | 2003 |
| Acre Capital Investments Limited | Administrative & support | 2019 |
| Acre City Limited | Hospitality | 2016 |
| Acre Heathrow Limited | Administrative & support | 2012 |
| Acre Hospitality Holdings Ltd | Financial services | 2026 |
| Acre Hotels Limited | Real estate | 2014 |
| Acre Kingston Limited | Construction | 2007 |
| Acre Manchester Limited | Real estate | 2015 |
| Acre Wood Real Estate Ltd | Real estate | 2024 |
| Acreage Holdings Limited | Real estate | 2017 |
| Acrely Ltd | Real estate | 2025 |
| Acress Limited | Real estate | 2021 |
| Across Media Limited | Administrative & support | 2022 |
| ACS Builders Ltd | Construction | 2022 |
| ACS Construction & Services Ltd | Construction | 2019 |
| Acsis Logistics Ltd | Transport & logistics | 2021 |
| Acsk Healthcare Ltd | Professional & scientific | 2023 |
| ACT Credit Management Limited | Administrative & support | 2004 |
| ACT Executive Limited | Professional & scientific | 2012 |
| Actaprint Holding Company Limited | Financial services | 2023 |
| Actaprint Limited | Wholesale & retail | 1974 |
| Action Cars Limited | Information & communication | 1991 |
| Action Engineers Limited | Construction | 2020 |
| Action Festival Holdings Limited | Information & communication | 2022 |
| Action Foods Limited | Wholesale & retail | 2018 |
| Action Homes & Property Limited | Real estate | 2021 |
| Action Signs & Graphics Limited | Professional & scientific | 2010 |
| Active Communities Network Limited | Arts & recreation | 2007 |
| Active Estate Planning Limited | Financial services | 2010 |
| Active Evolution Limited | Health & social care | 2017 |
| Active Kids Holiday Camps Ltd | Arts & recreation | 2025 |
| Active Online Limited | Wholesale & retail | 2016 |
| Acton Service Centre Limited | Wholesale & retail | 2012 |
| Acton Vale Properties Ltd | Real estate | 2026 |
| Actors Business Network Ltd | Education | 2021 |
| Actradinggoods Ltd | Wholesale & retail | 2023 |
| Acuity HCM Consulting Ltd | Information & communication | 2021 |
| Acumen Contractors Ltd | Construction | 2026 |
| Acumenadvancement Ltd | Transport & logistics | 2024 |
| Acupuncture & Homoeopathic Clinic Ltd | Health & social care | 2014 |
| ACV Design and Build Ltd | Construction | 2018 |
| AD Astra Digital Limited | Professional & scientific | 2017 |
| AD Eatery Ltd | Hospitality | 2024 |
| AD Facades Limited | Construction | 2022 |
| AD Index Limited | Professional & scientific | 2014 |
| AD N Sons Ltd | Wholesale & retail | 2025 |
| AD Tech Ltd | Construction | 2023 |
| AD Visor Ventures Ltd | Professional & scientific | 2006 |
| ADA Alliance Ltd | Real estate | 2023 |
| ADA Construct Ltd | Construction | 2023 |
| Adab Reality Limited | Real estate | 2022 |
| Adacel Limited | Professional & scientific | 2021 |