| Acubooks Ltd | Professional & scientific | 2024 |
| Acucomm Limited | Information & communication | 2012 |
| ACW Residential Ltd | Households | 2025 |
| Adam Powell Limited | Professional & scientific | 2026 |
| Adams & Creed Estate Agents Limited | Real estate | 2007 |
| Adder Group Ltd | Construction | 2020 |
| Addumine Ltd | Administrative & support | 2019 |
| Adept Ltd | Education | 2025 |
| Adept Paraplanning Ltd | Administrative & support | 2024 |
| Adhesion Consultants Limited | Professional & scientific | 2003 |
| Adlongstaffs Limited | Administrative & support | 2013 |
| Admin Fairy Ltd | Other services | 2021 |
| ADP Construction Limited | Construction | 2002 |
| ADR Performance Centre Ltd | Wholesale & retail | 2021 |
| Adralava Limited | Real estate | 1992 |
| Adseal Limited | Wholesale & retail | 1990 |
| Advanced Beauty and Aesthetics Kidderminster Ltd | Other services | 2024 |
| Adventure Consultancy Worldwide Ltd | Professional & scientific | 2022 |
| Adventures in Business Ltd | Information & communication | 2018 |
| ADW Utilities Limited | Construction | 2015 |
| Adzinnish Ltd | Transport & logistics | 2020 |
| Aesthetics Beauty by Camilla Limited | Health & social care | 2025 |
| Aesthetics by Charlie Ltd | Other services | 2026 |
| Affilink Ltd | Information & communication | 2024 |
| Afmh Property Developers Ltd | Real estate | 2024 |
| Afrinova Studio International Limited | Education | 2025 |
| Afxentore Ltd | Transport & logistics | 2023 |
| AG Plastering Contractors Limited | Construction | 2013 |
| Agri-Tech Ltd | Professional & scientific | 2019 |
| AH Automovements Limited | Transport & logistics | 2014 |
| AH Portfolio Limited | Real estate | 2022 |
| Ahvenanmaa Ltd | Administrative & support | 2022 |
| AI Mahmood Ltd | Wholesale & retail | 2022 |
| Aidenvine Limited | Real estate | 1983 |
| Aintin Ltd | Transport & logistics | 2019 |
| Air 8 Associates Ltd | Information & communication | 2024 |
| Air Tech ECS Limited | Professional & scientific | 2008 |
| Airducts Engineering Limited | Professional & scientific | 2006 |
| Airducts Holdings Limited | Professional & scientific | 2006 |
| Airline Business Limited | Transport & logistics | 1999 |
| Airtube Technologies Limited | Manufacturing | 2008 |
| Aiskew Ltd | Wholesale & retail | 2022 |
| AJ Automation Services Ltd | Manufacturing | 2025 |
| AJH Building Developments Ltd | Construction | 2025 |
| AJH Waste Management & Logistics Limited | Water & waste | 2024 |
| Ajjamo Ltd | Professional & scientific | 2026 |
| Ajjm TM Limited | Construction | 2024 |
| Ajoonee Limited | Wholesale & retail | 2016 |
| AJW Wills (Worcestershire) Limited | Other services | 2014 |
| AK Colletion Limited | Hospitality | 2024 |
| Akalimoto Ltd | Wholesale & retail | 2025 |
| Albianaphere Ltd | Transport & logistics | 2021 |
| Albion Gardens (Apartments) Management Company Limited | Households | 2001 |
| Albion Gardens Management Company Limited | Households | 2001 |
| Alderock Holdco Limited | Professional & scientific | 2023 |
| Alderock Property Limited | Real estate | 2023 |
| Aldubai TM Ltd | Construction | 2023 |
| ALG Live Events Limited | Administrative & support | 2009 |
| ALG Sound & Lighting (UK) Limited | Administrative & support | 2002 |
| Alice Westbury Coaching Limited | Health & social care | 2020 |
| Alina Maria Trans Ltd | Transport & logistics | 2021 |
| ALK Independent Financial Advisers Limited | Financial services | 2005 |
| ALL Electric Garages Group PLC | Wholesale & retail | 1967 |
| ALL Solutions Recruitment Ltd | Administrative & support | 2026 |
| Allilantro Ltd | Administrative & support | 2019 |
| Allness IT Limited | Information & communication | 2014 |
| Allsopp Flooring Limited | Wholesale & retail | 1996 |
| Allstar Environmental Limited | Water & waste | 2018 |
| Alltech Security Limited | Administrative & support | 2012 |
| Alltube Engineering Limited | Manufacturing | 2007 |
| Alma Transport & Logistics Ltd | Transport & logistics | 2025 |
| Alnwick Castle Ltd | Wholesale & retail | 2022 |
| Alpha B N K Renovations Ltd | Construction | 2025 |
| Alpha Bathrooms and Kitchens Limited | Construction | 2017 |
| Alpha Electrics & Renewables Limited | Construction | 2025 |
| Alphabarr Limited | Households | 1991 |
| Alpine International Xpress Transport Limited | Transport & logistics | 2008 |
| Alpirone Ltd | Health & social care | 2024 |
| Amada Essex Limited | Manufacturing | 1997 |
| Amaranthfire Ltd | Transport & logistics | 2020 |
| Amba Legal Services Limited | Professional & scientific | 2013 |
| Amber Terrace Block a RTM Company Limited | Households | 2024 |
| Amber Terrace Block B RTM Company Limited | Households | 2024 |
| AML Lawn Care Limited | Administrative & support | 2018 |
| Amodil Aerospace Ltd | Wholesale & retail | 2024 |
| Amodil Carbon & Alloy Ltd | Wholesale & retail | 2024 |
| Amodil Stainless Limited | Administrative & support | 2016 |
| Amodil Supplies Limited | Wholesale & retail | 1989 |
| Amtco Ltd | Other services | 2018 |
| Amtech Freight Services Limited | Transport & logistics | 2020 |
| AN Fire & Security Ltd | Administrative & support | 2022 |
| Anatolia Kiddy Ltd | Hospitality | 2020 |
| Anazenli Ltd | Administrative & support | 2024 |
| Anchors Away Ltd | Hospitality | 2023 |
| Andale Contracting Limited | Construction | 2005 |
| Anderlacum Ltd | Administrative & support | 2022 |
| Anderman & Company Limited | Wholesale & retail | 1947 |
| Anderman Ceramics Limited | Professional & scientific | 2001 |
| Anderson & Mcmaster Consultancy Ltd | Information & communication | 2026 |
| Andrea Louise Beers Limited | Health & social care | 2015 |