| 1080 Integration Limited | Professional & scientific | 2009 |
| 1405 Publishing Ltd | Other services | 2023 |
| 18 Ludlow Road Management Company Limited | Households | 2007 |
| 2 Left Paws Ltd | Professional & scientific | 2014 |
| 2020 AB Corporation Limited | Construction | 2019 |
| 2020 LS Enterprises Ltd | Real estate | 2018 |
| 22 Capital Group Ltd | Households | 2025 |
| 26 Point 2 Limited | Information & communication | 1999 |
| 26 Point 2 Solutions Ltd | Professional & scientific | 2011 |
| 3 Bulmershe Road (2004) Limited | Households | 2004 |
| 47 Beech Hill Road Sunningdale Limited | Real estate | 2022 |
| 4PERFORMANCE Ltd | Professional & scientific | 2024 |
| 4RF Communications (Europe) Limited | Information & communication | 2004 |
| 5G Tobacco Labs Ltd | Wholesale & retail | 2025 |
| 620 Media Ltd | Information & communication | 2020 |
| 77KW Limited | Information & communication | 2015 |
| 88AM Visuals Limited | Information & communication | 2023 |
| 98 London Road Freehold Limited | Households | 2013 |
| 998 Ltd | Information & communication | 2026 |
| A & P W Consultants Limited | Professional & scientific | 2002 |
| A Plus Motors Ltd | Wholesale & retail | 2022 |
| A R Thorn Enterprises Limited | Arts & recreation | 2016 |
| A. Cornish & Co. Limited | Construction | 1981 |
| A.D.P. Supplies Limited | Administrative & support | 1997 |
| A.R Saya Limited | Hospitality | 2026 |
| A4 Fuel Oils Ltd | Wholesale & retail | 2010 |
| AAS Accountants Ltd | Professional & scientific | 1990 |
| Aasa Homes Limited | Real estate | 2026 |
| Abbots Friars Residents Company Limited | Households | 1987 |
| Abbott Heating Ltd | Construction | 2019 |
| Abdico Records Ltd | Information & communication | 2024 |
| Abdt Properties Limited | Real estate | 2025 |
| Absolute Tyres Ltd. | Wholesale & retail | 2015 |
| AC Hair Extensions Ltd | Other services | 2026 |
| Ace Defence Security Limited | Administrative & support | 2016 |
| Acies Solutions Limited | Professional & scientific | 2011 |
| Adam Rennie Associates Limited | Health & social care | 2013 |
| ADD Melon Ltd | Professional & scientific | 2020 |
| Addington-Leavesden Limited | Real estate | 2024 |
| Advance Histopathology Laboratory Ltd | Professional & scientific | 2012 |
| Aegis Search Ltd | Administrative & support | 2024 |
| Aeromotion Ltd | Manufacturing | 2026 |
| AFP Wokingham Ltd | Financial services | 2023 |
| Agiv Limited | Other services | 2025 |
| Ahmad Construction Engineering Limited | Construction | 2007 |
| AI Genesis Ltd | Professional & scientific | 2023 |
| AIM Veritas Ltd | Professional & scientific | 2023 |
| Airtech Premier Limited | Administrative & support | 2005 |
| AJN Global Consultancy Services Ltd | Professional & scientific | 2026 |
| Akha Consultants Ltd | Professional & scientific | 1999 |
| Albury S.I. Limited | Professional & scientific | 1992 |
| Aleeda Limited | Construction | 2023 |
| Alexander House (Murdoch Road) Management Company Limited | Households | 2009 |
| Alexandra Couzens Coaching Ltd | Professional & scientific | 2024 |
| Algoritmus Limited | Information & communication | 2011 |
| Align YOU Limited | Health & social care | 2025 |
| Aligned Coaching Pathways Ltd | Health & social care | 2026 |
| Aligned Data Specifications (ADS) Alliance Limited | Administrative & support | 2026 |
| ALL Saints Hospitality Limited | Hospitality | 2017 |
| ALL Saints Residents (Maidenhead) Limited | Households | 1972 |
| Almira Consulting Limited | Information & communication | 2025 |
| Alphanom Capital Ltd | Financial services | 2022 |
| Altini Holdings Limited | Financial services | 2026 |
| Altini Westgate Commercial Limited | Real estate | 2026 |
| Altitude Digital Ltd | Information & communication | 2015 |
| Amelia Lane Beauty Ltd | Other services | 2020 |
| Amniomimesis Biotechnologies Ltd | Manufacturing | 2026 |
| Anba Ltd | Administrative & support | 2021 |
| Ancell Automation Ltd | Information & communication | 2026 |
| Andasu Properties Ltd | Real estate | 2025 |
| Andrew GOW Art Ltd | Arts & recreation | 2026 |
| Andrew Main & Co Ltd | Professional & scientific | 2017 |
| Anna Bieniek Limited | Financial services | 2026 |
| Anof Consulting Ltd | Professional & scientific | 2021 |
| Antiquesbyvera Ltd | Wholesale & retail | 2024 |
| Apex Plumber Ltd | Construction | 2023 |
| Apex Risk Assessments Limited | Financial services | 2023 |
| Apex Vault Limited | Administrative & support | 2026 |
| APM Consulting Ltd | Professional & scientific | 2026 |
| Applewood Management Company Limited | Households | 2017 |
| Aptrise Infosolutions UK Limited | Information & communication | 2025 |
| Aqua Active Limited | Wholesale & retail | 2020 |
| Aquajet Drainage Ltd | Water & waste | 2023 |
| Archer Kane LLP | | 2023 |
| Arco Investors Ltd | Financial services | 2025 |
| Arete Training Group Ltd | Education | 2024 |
| Ars-Sb Limited | Real estate | 2023 |
| Artkinsons Advisory Limited | Professional & scientific | 2026 |
| Ascot Top Hats Ltd | Manufacturing | 2006 |
| ASH Surgical Supplies Ltd | Wholesale & retail | 2024 |
| ASH Walls & Ceilings Ltd | Construction | 2023 |
| Ashdale Associates Limited | Professional & scientific | 2020 |
| Ashdale Park Management Company Limited | Households | 1984 |
| Ashley House Management Limited | Households | 2010 |
| Ashton R W LLP | | 2016 |
| Assagai Solutions Limited | Professional & scientific | 2005 |
| AT Makeup Ltd | Other services | 2019 |
| Augustfield Management Limited | Households | 2019 |
| Aura Chiropractic Ltd | Health & social care | 2024 |
| Aura Home Tech Ltd | Information & communication | 2009 |