| A2B Lighting Design Ltd | Professional & scientific | 2018 |
| A2Z Cars Midlands Ltd | Wholesale & retail | 2025 |
| A2Z Manufacturing Limited | Manufacturing | 2022 |
| A2Z Urban Conversions Ltd | Construction | 2024 |
| A2Z Urban Holdings Ltd | Financial services | 2024 |
| A5 Home Improvements Ltd | Construction | 2012 |
| A5 Logistics Limited | Transport & logistics | 2009 |
| AA Battery Recycling Limited | Water & waste | 2015 |
| AA Motor Traders Ltd | Wholesale & retail | 2025 |
| Aacka Community Interest Company | Education | 2025 |
| Aapv Limited | Real estate | 2018 |
| Aarya Enterprise Ltd | Wholesale & retail | 2019 |
| AB Property Services & SON Limited | Construction | 2021 |
| Abbey Green Carsales Ltd | Wholesale & retail | 2024 |
| Abbey Money and Property Limited | Real estate | 2014 |
| Abbey Physiotherapy Ltd | Health & social care | 2008 |
| Abbeybrook Limited | Households | 1992 |
| Abbotsfield Developments Limited | Real estate | 2006 |
| Abilitylife Services Ltd | Health & social care | 2024 |
| ABL Enterprise Ltd | Transport & logistics | 2020 |
| Ableton Ltd | Construction | 2021 |
| Abrasive Power Tools Limited | Wholesale & retail | 1998 |
| Abso Limited | Extraterritorial | 2015 |
| Abwelltrade Limited | Manufacturing | 2022 |
| AC Bakes & Desserts Ltd | Wholesale & retail | 2025 |
| AC Gani Transport Ltd | Transport & logistics | 2016 |
| Acacia Block B Management Limited | Households | 1987 |
| Academe Trainers | Public administration | 2021 |
| ACB Accountancy & Bookkeeping Ltd | Professional & scientific | 2021 |
| Access Solutions and Products Ltd | Manufacturing | 2020 |
| Accessible Orthodontics (O) Ltd | Health & social care | 2006 |
| Accl Stucks Limited | Professional & scientific | 2017 |
| Acclaim Transport Ltd | Transport & logistics | 2019 |
| Accountants Together Ltd | Professional & scientific | 2019 |
| Accounts to Accountants Ltd | Professional & scientific | 2018 |
| Accranut Company Limited(The) | Manufacturing | 1982 |
| Ace Carpentry & Joinery Contractors Limited | Manufacturing | 2000 |
| Ace Cleaning Services (Nuneaton) Limited | Administrative & support | 2003 |
| Ace Karting Limited | Arts & recreation | 2006 |
| Acel Holdings Limited | Professional & scientific | 2018 |
| Achelois Health Limited | Health & social care | 2015 |
| ACK Sales and Lettings Ltd | Real estate | 2023 |
| ACL Grinding Services Ltd | Professional & scientific | 2017 |
| ACM Property (Midlands) Ltd | Real estate | 2022 |
| Acock Ltd | Wholesale & retail | 2021 |
| Acorn Wood Holdings Limited | Education | 2023 |
| Acorn Wood Nursery Limited | Education | 2023 |
| Acquire Capital Ventures Ltd | Financial services | 2023 |
| Acsap Limited | Construction | 2011 |
| Active Plates Ltd | Wholesale & retail | 2025 |
| ACTIVE8EDUCATION Ltd | Health & social care | 2026 |
| Activhealth Ltd | Health & social care | 2022 |
| Adaco Healthcare Ltd | Health & social care | 2020 |
| Adaptive Business Solutions Limited | Information & communication | 2009 |
| Addam Properties Ltd | Real estate | 2025 |
| Addaptx Ltd | Manufacturing | 2024 |
| Adder Machine Services Limited | Administrative & support | 2008 |
| Addiscombe Road Managment Company Limited | Hospitality | 2007 |
| Additions Installations & Service Limited | Construction | 2004 |
| Adeseius Ltd | Information & communication | 2022 |
| Adhamgargar Limited | Other services | 2024 |
| ADI Midlands Limited | Construction | 2010 |
| Adi-Automotive Ltd | Professional & scientific | 2024 |
| Adlid Express Ltd | Transport & logistics | 2026 |
| ADR Jointing Limited | Construction | 2018 |
| ADR Motorworks Ltd | Wholesale & retail | 2024 |
| ADS Purchase & Supply Limited | Other services | 2009 |
| Adstrans Ltd | Transport & logistics | 2016 |
| Aduk Products Limited | Professional & scientific | 2011 |
| Adunmade and Co Ltd | Wholesale & retail | 2020 |
| Advanced Data Systems Limited | Information & communication | 2003 |
| Advanced Diagnostics Limited | Professional & scientific | 2002 |
| Advanced Electrical Controls Limited | Construction | 2007 |
| Advanced Manufacturing Control Systems UK Limited | Information & communication | 2006 |
| Advanced Tree Surgery Limited | Agriculture & fishing | 2026 |
| Advantageous Enterprises Ltd | Wholesale & retail | 2023 |
| ADVECTION7 Limited | Professional & scientific | 2023 |
| ADY Mary Ltd | Transport & logistics | 2022 |
| ADY Trans Serv Ltd | Transport & logistics | 2015 |
| Aegean Stone Limited | Manufacturing | 2003 |
| Aegis Biometric Ltd | Information & communication | 2026 |
| Aegis Overseas Education Services Private Limited | Information & communication | 2026 |
| Aeon Health Concepts Ltd | Health & social care | 2023 |
| Aeon Property Investment Company Limited | Real estate | 2024 |
| Aerialvisionmedia Ltd | Manufacturing | 2024 |
| Aerosimo Ltd | Information & communication | 2018 |
| Aerotech Innovation Limited | Professional & scientific | 2011 |
| Aesthetic Skin by A.S. Limited | Other services | 2025 |
| Aesthetica Dermal Clinic Ltd | Wholesale & retail | 2019 |
| AF Carpentry and Home Improvement Ltd | Manufacturing | 2023 |
| AF Serv Ltd | Transport & logistics | 2020 |
| Afro Grill & Catering Ltd | Hospitality | 2023 |
| Afterdark Creative Ltd | Construction | 2021 |
| AFZ Labs Ltd | Information & communication | 2026 |
| Agal Retail Ltd | Wholesale & retail | 2020 |
| AGE Investments Ltd | Real estate | 2020 |
| Aggbag Limited | Mining & quarrying | 2000 |
| Aggrecycle Holdings Limited | Financial services | 2024 |
| Aggrecycle Limited | Financial services | 2023 |
| Agiba Limited | Professional & scientific | 2022 |