| ACA Transport Ltd | Transport & logistics | 2019 |
| Acacia United Company Limited | Information & communication | 2026 |
| Academic Edge Ltd | Education | 2023 |
| Academy for International Education and Research Limited | Manufacturing | 2019 |
| Academy of Elite Training Limited | Education | 2023 |
| Acakgee Ltd | Wholesale & retail | 2026 |
| Acceleratus Services Ltd | Information & communication | 2014 |
| Access Heat Ltd | Construction | 2023 |
| Accessedu Community Interest Company | Education | 2025 |
| Accesta Limited | Information & communication | 2018 |
| Accident Claims Hotline Limited | Administrative & support | 2001 |
| Accident Management Direct Line Limited | Other services | 2006 |
| Accodigi Limited | Information & communication | 2026 |
| Accommease Properties Limited | Real estate | 2025 |
| Accommflow Properties Limited | Hospitality | 2025 |
| Accomp Ltd | Professional & scientific | 2014 |
| Account-Ease Ltd | Professional & scientific | 2019 |
| Accountancy Global Services Ltd | Professional & scientific | 2011 |
| Accountant for Business Ltd | Professional & scientific | 2022 |
| Accountants & Associates Limited | Real estate | 2010 |
| Accountants 4 YOU Limited | Professional & scientific | 2019 |
| Accountax Advice Limited | Professional & scientific | 2019 |
| Accounts First Consultancy Ltd | Administrative & support | 2005 |
| Accounts Tax Assistance Ltd | Professional & scientific | 2022 |
| Accueil Lettings Limited | Real estate | 2018 |
| Accugrit Limited | Administrative & support | 2019 |
| Accurasol Limited | Information & communication | 2025 |
| Accuspark Ignition Systems Ltd | Wholesale & retail | 2011 |
| ACD Plumbers Ltd | Construction | 2018 |
| Ace & Spin Investment Limited | Financial services | 2026 |
| Ace Active Consultants Ltd | Arts & recreation | 2021 |
| Ace Aluminium Scaffolding Limited | Information & communication | 2026 |
| Ace and Spin Ltd | Arts & recreation | 2025 |
| Ace Caterers Limited | Hospitality | 2020 |
| Ace Coconut Charcoal Limited | Manufacturing | 2023 |
| Ace Consultancy Enterprises Ltd | Professional & scientific | 2017 |
| Ace Cutz Barbers Ltd | Other services | 2026 |
| Ace Designs Limited | Professional & scientific | 2016 |
| Ace Educators Ltd | Education | 2025 |
| Ace FIX Services Limited | Other services | 2026 |
| Ace ICT 247 Ltd | Information & communication | 2016 |
| Ace Infrastructure Ltd | Construction | 2024 |
| Ace Kutz Limited | Other services | 2026 |
| Ace LET Luton Ltd | Households | 2017 |
| Ace PRE Construction Services Ltd | Construction | 2021 |
| Ace Property Enterprises Limited | Real estate | 2023 |
| Ace Rich Ltd | Wholesale & retail | 2024 |
| Ace Taxi Limited | Transport & logistics | 2022 |
| Ace-Tech Global Company LLC Limited | Information & communication | 2025 |
| Aceko Ltd | Administrative & support | 2016 |
| Acer Prime Properties Ltd | Real estate | 2021 |
| ACF Investments Ltd | Real estate | 2015 |
| Acgs Investments Limited | Arts & recreation | 2024 |
| Achiben Ltd | Real estate | 2024 |
| Achibmo Ltd | Information & communication | 2019 |
| Achievers Construction Limited | Construction | 2025 |
| Achilles Homes Ltd | Construction | 2026 |
| Achilles Residential Acquisitions Limited | Real estate | 2026 |
| Achonry Investments Ltd | Real estate | 2024 |
| Achtrad Limited | Wholesale & retail | 2015 |
| Aciers Development Limited | Real estate | 2024 |
| Aciers Food Limited | Hospitality | 2025 |
| ACL Management Services Ltd | Hospitality | 2024 |
| ACM Body Shop Limited | Wholesale & retail | 2024 |
| ACM Freight & Logistics Limited | Transport & logistics | 2025 |
| Acme Education UK Limited | Education | 2014 |
| Acme Trading Ltd | Wholesale & retail | 2025 |
| ACN Property Limited | Real estate | 2023 |
| Acoet Limited | Professional & scientific | 2012 |
| Acorn Building Services (Luton) Limited | Construction | 1998 |
| Acorn Day Care Limited | Health & social care | 2022 |
| Acorn Investments Ltd | Other services | 2015 |
| ACP Properties Ltd | Real estate | 2019 |
| Acpes Consulting Ltd | Administrative & support | 2017 |
| Acquasis Capital Ltd | Information & communication | 2019 |
| Acquility Ltd | Other services | 2017 |
| Acquire Matsa Group Ltd | Administrative & support | 2026 |
| Acquiro Global Ltd | Wholesale & retail | 2025 |
| Acraenterprise Ltd | Real estate | 2025 |
| Acron Services Ltd | Wholesale & retail | 2023 |
| ACS Fire Protection Limited | Professional & scientific | 2017 |
| ACT (Luton) Limited | Real estate | 2016 |
| Act-Building Services Ltd | Construction | 2020 |
| Actimec Limited | Construction | 2020 |
| Action Circuits (U.K.) Limited | Information & communication | 1987 |
| Action Circuits Holdings Limited | Professional & scientific | 2016 |
| Action Weld Limited | | 1990 |
| Actionpace Limited | Real estate | 1996 |
| Active Chauffeurs Ltd | Transport & logistics | 2026 |
| Active Education Academy Trust | Education | 2011 |
| Active Environmental Limited | Construction | 2017 |
| Active Estates Limited | Real estate | 2014 |
| Active Facilities Limited | Administrative & support | 2023 |
| Active Kids Nursery Ltd. | Education | 2015 |
| Active Luton | Education | 2005 |
| Active Luton Enterprises Limited | Wholesale & retail | 2005 |
| Active Motors Ltd | Wholesale & retail | 2024 |
| Active Support (Luton) Limited | Education | 2007 |
| Active Support 16+ Ltd | Arts & recreation | 2009 |
| Active Support Education Centre Ltd | Education | 2013 |