| Abraham Solicitors Ltd | Professional & scientific | 2010 |
| Abrey Construction Holdings Ltd | Financial services | 2025 |
| Abrey Developments Limited | Construction | 2013 |
| Abrikate Ltd | Wholesale & retail | 2026 |
| Absolute Sanitisers Limited | Manufacturing | 2020 |
| Abugumah Limited | Health & social care | 2025 |
| AC Civil Engineering Ltd | Construction | 2017 |
| AC Electrical & Renewables Ltd | Construction | 2023 |
| Ac's Property Services Ltd | Construction | 2023 |
| Ac/Dc Electrical Solutions Ltd | Construction | 2007 |
| Acab Consultancy Services Ltd | Administrative & support | 2025 |
| ACB Accountancy Services Ltd | Professional & scientific | 2018 |
| Access & Explore Ltd | Construction | 2025 |
| Access Alternatives Limited | Wholesale & retail | 2007 |
| Access Care Alerts Limited | Health & social care | 2015 |
| ACD Plastering Contractors Ltd | Construction | 2019 |
| Ace Felt Roofing Ltd | Construction | 2011 |
| Ace Play Limited | Other services | 2010 |
| Ace Welfare Hire Ltd | Administrative & support | 2021 |
| Acheron Electrical Limited | Construction | 2022 |
| Acme Websters Limited | Transport & logistics | 2025 |
| Acorn Kennels Limited | Agriculture & fishing | 2021 |
| Acorn Property & Landscaping Limited | Construction | 2018 |
| ACS Air Conditioning Ltd | Construction | 2004 |
| Actiroam Ltd | Manufacturing | 2025 |
| Active Childcare Holdings Limited | Health & social care | 2017 |
| Active Childcare Limited | Education | 2003 |
| Active Management Corporation Limited | Other services | 2019 |
| Activkids UK Ltd | Education | 2023 |
| Acton Edocs Systems Ltd | Information & communication | 2019 |
| Acton Financial Services Ltd | Financial services | 2021 |
| Acton Gate Audio Limited | Wholesale & retail | 2000 |
| Acton Health & Safety & Fire Safety Ltd | Professional & scientific | 2014 |
| Acton Web Services Ltd | Information & communication | 2022 |
| AD Health & Beauty Limited | Wholesale & retail | 2022 |
| AD Window Cleaning Ltd | Administrative & support | 2013 |
| Adapt Recruitment Group Limited | Administrative & support | 2022 |
| ADD Mart Joinery & Shopfitting Limited | Construction | 2010 |
| Addabow Ltd | Wholesale & retail | 2021 |
| Addicted Marketing Ltd | Professional & scientific | 2022 |
| Adhd LAB UK Ltd | Health & social care | 2026 |
| Adigileap Limited | Information & communication | 2024 |
| ADT Logistics Limited | Transport & logistics | 2026 |
| Advance Enterprises (Automation) Limited | Wholesale & retail | 2010 |
| Advance Park Limited | Professional & scientific | 2003 |
| Advance Spares Limited | Manufacturing | 1986 |
| Adventure Tours U.K. Ltd | Administrative & support | 2018 |
| Advisely Energy Ltd | Information & communication | 2022 |
| Advocate Compliance Ltd | Administrative & support | 2012 |
| ADW Property Maintenance Limited | Construction | 2024 |
| ADY Jones TAE Kwon DO Academy (Wrexham) LLP | | 2016 |
| AE Sewing Machines Ltd | Wholesale & retail | 2016 |
| Aero PR Ltd | Professional & scientific | 2024 |
| Aero-Crop Solutions Ltd | Agriculture & fishing | 2019 |
| Afell Consulting Ltd | Professional & scientific | 2023 |
| Affiniture Cards Limited | Financial services | 2011 |
| Affiniture Group Limited | Financial services | 2021 |
| Affinity Electrical Solutions Ltd | Construction | 2017 |
| Afford Housing Group UK Ltd | Real estate | 2019 |
| AG Engineering Ltd. | Information & communication | 2026 |
| AG Real Estate Wrxhm Ltd | Real estate | 2025 |
| AG Snailum Ltd | Administrative & support | 2022 |
| Agata Williams Limited | Health & social care | 2023 |
| Agentic Artificial Intelligence Limited | Professional & scientific | 2025 |
| Agera Innovations Ltd | Wholesale & retail | 2026 |
| Agera Limited | Construction | 2016 |
| Agile Delivery Solutions Ltd | Information & communication | 2011 |
| AGM Plastics Limited | Manufacturing | 2007 |
| AGN Holiday Lets Ltd | Hospitality | 2025 |
| AGN Properties Ltd | Real estate | 2022 |
| AGR Electrical Limited | Energy | 2018 |
| Agri Pro Corp Limited | Agriculture & fishing | 2024 |
| Agri-Cation CIC | Education | 2020 |
| Agritel Limited | Wholesale & retail | 1996 |
| Agwalker Consulting Ltd | Professional & scientific | 2014 |
| Ahad Transport and Auto Services Ltd | Wholesale & retail | 2025 |
| AHW Management Limited | Households | 2004 |
| AI Growth Tech Ltd | Information & communication | 2026 |
| AI Online Ltd | Professional & scientific | 2022 |
| Ai.T Ltd | Information & communication | 2024 |
| Aiker Legal Limited | Administrative & support | 2021 |
| Ainsley's Industrial Flooring Limited | Construction | 2003 |
| Aintree Holsteins Limited | Agriculture & fishing | 2002 |
| Air Covers Limited | Manufacturing | 2006 |
| Air Mechanics Ltd | Wholesale & retail | 2025 |
| Airsec Medical Services Limited | Health & social care | 2026 |
| Aisoft Limited | Information & communication | 2026 |
| AJ & JR Property Limited | Real estate | 2025 |
| AJ Steelerection Rigging and Lifting Ltd | Construction | 2025 |
| Ajak Developments Ltd | Real estate | 2018 |
| Ajcs Logistics Ltd | Transport & logistics | 2018 |
| AJH Inspection Services Limited | Professional & scientific | 2014 |
| AJI Accounting Solutions Ltd | Professional & scientific | 2003 |
| AJN Lifestyle Limited | Wholesale & retail | 2019 |
| AJP Commercial Properties Ltd | Real estate | 2024 |
| AJP Couriers (Nationwide) Limited | Transport & logistics | 2017 |
| AJP Edwards Consulting Ltd | Professional & scientific | 2019 |
| AJR Accounting Services Limited | Professional & scientific | 2009 |
| AJS Workwear Ltd | Wholesale & retail | 2017 |
| Ajtr Ventures Ltd | Financial services | 2026 |