| Active Response Transport Ltd | Administrative & support | 2014 |
| Acun Pizza Ltd | Hospitality | 2025 |
| ACW Aviation Limited | Manufacturing | 2013 |
| AD Electronic Design Ltd | Manufacturing | 2022 |
| AD Heating Services Limited | Construction | 2023 |
| AD Units Limited | Real estate | 2022 |
| AD Vehicle Customisation Ltd | Wholesale & retail | 2025 |
| Adam Asian Takeaway Ltd | Hospitality | 2024 |
| Adam Developments Ltd | Real estate | 2010 |
| Adam Mini Market Ltd | Wholesale & retail | 2026 |
| Adam Russell Construction Ltd | Construction | 2023 |
| Adam Zumwalt Aesthetics Ltd | Other services | 2026 |
| Adapt Brickwork Ltd | Construction | 2024 |
| Adapt Interiors Ltd | Construction | 2017 |
| ADB Surveying Limited | Professional & scientific | 2001 |
| Adband Limited | Administrative & support | 2012 |
| ADD Logistics Ltd | Transport & logistics | 2018 |
| Adderha Ltd | Professional & scientific | 2013 |
| Addistone Investments Limited | Real estate | 2023 |
| Adds Transport Limited | Transport & logistics | 2026 |
| Adele Jones Hairdressing Limited | Real estate | 2014 |
| Adelphi Mechanical Ltd | Construction | 2024 |
| Adelphi Recruitment Europe Ltd | Administrative & support | 2022 |
| Adenncast Limited | Information & communication | 2017 |
| Adept Cleaning & Maintenance Services Ltd | Administrative & support | 2000 |
| Adesco Group Limited | Professional & scientific | 2024 |
| Adesquare Care Ltd | Public administration | 2019 |
| ADG Office Ltd | Transport & logistics | 2022 |
| ADH Joinery Services Ltd | Construction | 2025 |
| Adils Properties Limited | Real estate | 2018 |
| Adler Property Group Ltd | Real estate | 2026 |
| Adnan Accounting & Advisory Ltd | Professional & scientific | 2026 |
| Adonis Property Developments Ltd | Construction | 2017 |
| ADR Heating Solutions Ltd | Construction | 2012 |
| Adrenalin 4X4 Limited | Wholesale & retail | 2009 |
| Adrenaline Fuelled Limited | Manufacturing | 2022 |
| Adriano Car Wash Limited | Administrative & support | 2023 |
| ADS Precision Limited | Manufacturing | 2000 |
| ADS Windows, Doors and Conservatories Ltd. | Manufacturing | 2008 |
| ADT Electronics Limited | Other services | 2022 |
| Advance Basketball Ltd | Arts & recreation | 2023 |
| Advance Formation CIC | Professional & scientific | 2025 |
| Advanced Drive Ltd | Administrative & support | 2020 |
| Advanced Drywall Solutions Limited | Construction | 2023 |
| Advanced Drywall Systems Limited | Construction | 2014 |
| Advanced Electrical & Charging Ltd | Households | 2022 |
| Advanced Electrical Solutions (Yorkshire) Ltd | Other services | 2018 |
| Advanced GAS Disconnections Ltd | Other services | 2019 |
| Advanced Intelligent PAY Ltd | Other services | 2021 |
| Advanced Intelligent Technologies Limited | Information & communication | 2025 |
| Advanced Manufacturing (Sheffield) Limited | Manufacturing | 2002 |
| Advanced Manufacturing Holdings Limited | Financial services | 2021 |
| Advanced Tent Engineering Limited | | 1988 |
| Advantage Motors Ltd | Wholesale & retail | 2021 |
| Advantage Recycling Limited | Professional & scientific | 2025 |
| Adventure Avenue Ltd | Health & social care | 2025 |
| Advice YOU CAN Trust Limited | Financial services | 2024 |
| Adysof Ltd | Transport & logistics | 2024 |
| AE Rail Limited | Transport & logistics | 2015 |
| AEL Consulting (South Yorkshire) Limited | Health & social care | 2020 |
| Aeon Financial Group Ltd | Financial services | 2021 |
| Aeon Financial Services Limited | Financial services | 1996 |
| Aeon Group Holdings Limited | Financial services | 2025 |
| Aepex Engineering Limited | Professional & scientific | 2022 |
| Aequora UK Ltd | Wholesale & retail | 2026 |
| Aerial Movement Limited | Education | 2025 |
| Aerial Zone Ltd | Arts & recreation | 2022 |
| Aerovision Drone Services UK Ltd | Information & communication | 2024 |
| Aesseal Marine PLC | Manufacturing | 2005 |
| Aesthetiq Solutions Ltd | Other services | 2016 |
| AEX ARV Ltd | Transport & logistics | 2019 |
| AFC Developments Ltd | Real estate | 2019 |
| Affewe Properties Ltd | Real estate | 2025 |
| Affiliate Leads Ltd | Information & communication | 2016 |
| Affordable Baby Care Limited | Wholesale & retail | 2003 |
| Affordable Carpets and Blinds Limited | Wholesale & retail | 2018 |
| Affordable Detailing Services Limited | Administrative & support | 2026 |
| Affordable Quality Autos Ltd | Wholesale & retail | 2026 |
| AFN Industrial Services Limited | Construction | 2021 |
| Afri Panel Beaters Limited | Wholesale & retail | 2025 |
| Africa's Gift Limited | Agriculture & fishing | 2012 |
| Afrotec Industries Limited | Administrative & support | 2005 |
| AFT Engineering Ltd | Construction | 2019 |
| Aftab Trading Limited | Wholesale & retail | 2021 |
| AFY Ltd | Wholesale & retail | 2020 |
| AG BA Services Ltd | Professional & scientific | 2022 |
| AG Real Estate & Holding Limited | Real estate | 2025 |
| AGA Build Ltd | Construction | 2022 |
| Agam Catering Equipment Ltd | Wholesale & retail | 2020 |
| Agate Consult Limited | Health & social care | 2023 |
| Agathah Limited | Hospitality | 2018 |
| AGE UK Rotherham Limited | Health & social care | 1985 |
| Agent Pilot Ltd | Information & communication | 2025 |
| Agha Shop Ltd | Wholesale & retail | 2025 |
| AGI Analtyics Ltd | Information & communication | 2025 |
| AGL Residential Ltd | Real estate | 2025 |
| AGM Motors Ltd | Wholesale & retail | 2025 |
| Agrarian Call Ltd | Real estate | 2020 |
| Agroman Limited | Professional & scientific | 2015 |
| AGS Healthcare Ltd | Health & social care | 2025 |