| Accountants Waterlooville Limited | Extraterritorial | 2019 |
| Accounting Southern Limited | Professional & scientific | 2015 |
| Accountkeeping Solutions Ltd | Professional & scientific | 2012 |
| Accs Total Training Limited | Other services | 2018 |
| Accurad Imaging Limited | Health & social care | 2026 |
| Accurate Building Services Limited | Construction | 2008 |
| Accurate Tool Repair & Supplies Limited | Manufacturing | 2011 |
| ACD Management Services Limited | Information & communication | 2025 |
| Acdc Assets Limited | Real estate | 2023 |
| Ace Consultancy Expert Services (Aces) Limited | Information & communication | 2021 |
| Ace Decor Services Limited | Construction | 2018 |
| Ace TV & Aerial Installations Ltd | Construction | 2013 |
| Achieve Recruitment Ltd | Administrative & support | 2024 |
| Achilles Property Limited | Real estate | 2020 |
| ACI Auto Sales Limited | Wholesale & retail | 2025 |
| ACI Autos Group Limited | Wholesale & retail | 2025 |
| Acorn Accounting Solutions Limited | Professional & scientific | 1995 |
| Acre Lawn Turf Limited | Administrative & support | 2017 |
| ACT Self Defence CIC | Arts & recreation | 2022 |
| Activate Horizon Ltd | Financial services | 2025 |
| Activate Trade Training Ltd | Professional & scientific | 2020 |
| Active Financial Partners Limited | Financial services | 2001 |
| Active Outreach Services Limited | Education | 2023 |
| Active Rail Solutions Ltd | Construction | 2024 |
| Active Wealth Estates Ltd | Financial services | 2015 |
| ACTIVE8 Minds Winchester Ltd | Education | 2023 |
| Actsafe Training Services Limited | Administrative & support | 2025 |
| AD Astra Childrens Home Ltd | Health & social care | 2024 |
| AD Astra Enterprises Limited | Financial services | 2025 |
| AD Astra Estates Limited | Real estate | 2025 |
| AD Automotive Ltd | Manufacturing | 2023 |
| AD Equestrian Ltd | Administrative & support | 2020 |
| AD Recruit Limited | Administrative & support | 2023 |
| AD Saddlery Services Ltd | Professional & scientific | 2024 |
| ADA Solutions Limited | Professional & scientific | 2004 |
| ADB Software Limited | Information & communication | 2022 |
| Addems Capital Ltd. | Financial services | 2026 |
| Adegunwa Marshall Property Limited | Real estate | 2024 |
| Adelta Plumbing & Heating Ltd | Administrative & support | 2017 |
| Adewale-Anike Property Group Ltd | Real estate | 2026 |
| Adhurst Limited | Hospitality | 2020 |
| Admaco Limited | Financial services | 2022 |
| Admiral Waste Recycling and Maintenance Limited | Water & waste | 2017 |
| Adora Hospitality Ltd | Hospitality | 2024 |
| Adore Maintenance Ltd | Manufacturing | 2023 |
| ADP Developments Limited | Construction | 2024 |
| Adrian Edwards Clinical Psychology Limited | Health & social care | 2025 |
| Aduvant Developments Ltd | Construction | 2024 |
| Advance Scaffolding Limited | Construction | 2002 |
| Advance SRM Therapies Ltd | Health & social care | 2020 |
| Advancecentre Limited | Information & communication | 2000 |
| Advanced Aeration Ltd | Water & waste | 2009 |
| Advanced Cooling Southern Limited | Energy | 2022 |
| Advanced Fleet Care Limited | Wholesale & retail | 2022 |
| Advanced Husbandry Ltd | Wholesale & retail | 2021 |
| Advanced Physio Solutions Limited | Health & social care | 2018 |
| Advanced Trade Services Limited | Construction | 2015 |
| AE Financial Services Limited | Financial services | 1998 |
| Aegis Safety Consulting Ltd | Professional & scientific | 2025 |
| Aertek Limited | Transport & logistics | 2010 |
| Aerw Consulting Limited | Professional & scientific | 2024 |
| AES Property Investments Limited | Real estate | 2019 |
| Aestheticlinix Ltd | Other services | 2023 |
| Aesthetics Edge Limited | Administrative & support | 2025 |
| Aesthetx Ltd | Health & social care | 2023 |
| Aetec Ltd | Transport & logistics | 2013 |
| Affinity Comms Limited | Professional & scientific | 2020 |
| Affordable Design Limited | Professional & scientific | 2006 |
| AFRAGRANCE4U Ltd | Wholesale & retail | 2019 |
| AG Arboriculture Limited | Professional & scientific | 2024 |
| AGE of Heroes Producers Pool Limited | Information & communication | 2010 |
| Agencyland Network Ltd | Other services | 2024 |
| AGL Accounting Services Ltd | Professional & scientific | 2021 |
| AGS Renovations Southern Limited | Construction | 2014 |
| Agys Consulting Ltd | Information & communication | 1991 |
| AH Trans Ltd | Wholesale & retail | 2017 |
| AHA Horizon Limited | Real estate | 2015 |
| Ahco Holdings Ltd | Real estate | 2018 |
| AHI Engineering Solutions Ltd | Professional & scientific | 2025 |
| Ahshop Limited | Wholesale & retail | 2020 |
| AI Beluga Ltd | Information & communication | 2025 |
| AI Broker Solutions Ltd | Information & communication | 2026 |
| Aiden Barber Ltd | Other services | 2023 |
| Air Performance Ltd | Energy | 2018 |
| Airbear Properties Limited | Households | 2019 |
| Airmanage ME Limited | Hospitality | 2020 |
| AJ Cosmetic Clinic Ltd | Health & social care | 2023 |
| AJ Pro Fade Ltd | Other services | 2026 |
| AJA & Associates Ltd | Professional & scientific | 2020 |
| AJL Policing Solutions Limited | Administrative & support | 2015 |
| AJP Consulting Ltd | Professional & scientific | 2022 |
| Ajrb Services Limited | Information & communication | 2019 |
| AJV Groundworks Limited | Construction | 2018 |
| AJW Electrical Limited | Construction | 1998 |
| AK Health Direct Limited | Wholesale & retail | 2024 |
| AKF Holdings Limited | Professional & scientific | 2024 |
| Akino Ltd | Wholesale & retail | 2024 |
| AKL Digital Limited | Information & communication | 2024 |
| AKM Limousines Limited | Transport & logistics | 2006 |
| AKP Maintenance Ltd | Construction | 2014 |