| Ascendant Information Management Limited | Manufacturing | 2002 |
| Ascentia Consulting Solutions Ltd | Professional & scientific | 2025 |
| Ascot 360 Photo Booth Ltd | Administrative & support | 2024 |
| Ascot Awnings and Shutters Limited | Construction | 2020 |
| Ascot Building Ltd | Construction | 2024 |
| Ascot Digital Ltd | Information & communication | 2022 |
| Ascot Meadows Limited | Health & social care | 2010 |
| Ascot Property Service Limited | Construction | 2019 |
| Ascot Roofing Limited | Construction | 2015 |
| Ascot Trading Ltd | Hospitality | 2025 |
| ASD Design & Build Ltd | Construction | 2024 |
| Asgard Medical Ltd | Health & social care | 2019 |
| ASH Investments Limited | Real estate | 1964 |
| Ashfaq Ahmad Empire Ltd | Wholesale & retail | 2025 |
| Ashleigh's Little Angels Childcare and Creche Ltd | Health & social care | 2019 |
| Ashley Blair Euro Properties Limited | Real estate | 2005 |
| Ashra Homes Ltd | Real estate | 2019 |
| Asht Lakshmi Limited | Real estate | 2025 |
| Asian Tiger Cuisine Ltd | Hospitality | 2018 |
| Asili Ilisa Ltd. | Extraterritorial | 2025 |
| ASK Propertiez Limited | Real estate | 2026 |
| ASM Trinity Retail Limited | Wholesale & retail | 2024 |
| Asmart ATJ Recovery Limited | Mining & quarrying | 2003 |
| Aspira Living Ltd | Real estate | 2025 |
| Aspire (Swansea) Limited | Financial services | 2012 |
| Aspire Support Options Limited | Administrative & support | 2012 |
| Assetico Limited | Professional & scientific | 2003 |
| Assurtech Ltd | Information & communication | 2024 |
| AST Tile & Stone LLP | | 2017 |
| Asterisk Business Systems Limited | Information & communication | 2019 |
| Aston Carter International Limited | Administrative & support | 2002 |
| Astor & Bruno Limited | Transport & logistics | 2016 |
| Astrove Ltd | Wholesale & retail | 2023 |
| AT Home Care 4U Limited | Health & social care | 2024 |
| ATA Accountax Ltd | Professional & scientific | 2026 |
| Atec CG Limited | Construction | 2025 |
| ATJ Afhagrp Recovery Limited | Mining & quarrying | 2017 |
| Atkingells Ltd | Health & social care | 2012 |
| Atlas Appliance Group Ltd | Other services | 2026 |
| Atlas Project and Programme Management Limited | Professional & scientific | 2015 |
| Atmosphere IT Limited | Information & communication | 2019 |
| ATR Associates Limited | Transport & logistics | 2023 |
| Attikas Ltd | Information & communication | 2008 |
| Audetect Limited | Financial services | 2018 |
| Audio Electronics Ltd | Manufacturing | 2019 |
| Audiofinity Limited | Professional & scientific | 2025 |
| Audley Group Services Limited | Real estate | 1986 |
| Audley Properties Services Limited | Extraterritorial | 1995 |
| Auntie Em's Boutique LLP | | 2013 |
| Aurix BEV Ltd | Wholesale & retail | 2026 |
| Aurora Sky Creations Ltd | Information & communication | 2023 |
| Aurora Strategy Group Limited | Construction | 2022 |
| Aurora Strategy Investment Limited | Financial services | 2022 |
| Austin Way Management Limited | Real estate | 2017 |
| Autocode Diagnostics Ltd | Wholesale & retail | 2025 |
| Autonomous Point of Sale Limited | Information & communication | 2020 |
| Autumnfall Consultants Limited | Administrative & support | 2014 |
| Avalonian Gardens Ltd | Administrative & support | 2022 |
| Avatar Recruitment Consultancy Limited | Administrative & support | 2010 |
| Avco Properties Limited | Real estate | 2023 |
| Avds Properties Ltd | Real estate | 2025 |
| Aved Ltd | Transport & logistics | 2020 |
| Avien Roofing Ltd | Construction | 2022 |
| Avis Budget Services Limited | Administrative & support | 1985 |
| Avis Europe and Middle East Limited | Administrative & support | 1997 |
| Avis Europe Holdings Limited | Professional & scientific | 1986 |
| Avis Finance Company Limited | Administrative & support | 1987 |
| Avsmile Holding Properties Ltd | Administrative & support | 2020 |
| AWA Transport 2016 Ltd | Transport & logistics | 2025 |
| AWD Traders Limited | Wholesale & retail | 2025 |
| Axika Limited | Construction | 2018 |
| Ayaana 2008 Limited | Health & social care | 2017 |
| Ayata Group Ltd. | Information & communication | 2016 |
| Ayla Housing Ltd | Real estate | 2023 |
| Aylen Consulting Ltd | Information & communication | 2018 |
| Ayo's Kitchen L Ltd | Hospitality | 2024 |
| Ayo's Kitchen Limited | Hospitality | 2026 |
| Ayoola Olajide Limited | Public administration | 2022 |
| Ayres Audits Limited | Wholesale & retail | 2023 |
| Ayreswood Ltd | Financial services | 2025 |
| Aztech Plumbing & Maintenance Ltd | Wholesale & retail | 2025 |
| B & M Holdings Limited | Financial services | 2021 |
| B & W Stays Ltd | Hospitality | 2003 |
| B C Technologies LLP | | 2004 |
| B H Investments Ltd. | Real estate | 2017 |
| B S Services (Ascot) Limited | Real estate | 2009 |
| B T Barber Ltd | Other services | 2026 |
| B-Eat-Iful Ltd | Hospitality | 2019 |
| B-Tech Engineering Limited | Manufacturing | 2003 |
| B-Wise Management Services Ltd | Professional & scientific | 2017 |
| B.O.B Salons Ltd | Other services | 2012 |
| B247 Limited | Health & social care | 2024 |
| B2B Drum Ltd | Information & communication | 2025 |
| B:Well Consulting Ltd | Extraterritorial | 2020 |
| BA Infotech Limited | Information & communication | 2017 |
| Baban Barber 7 Ltd | Other services | 2026 |
| Baby Grand Events and Entertainment Ltd | Professional & scientific | 2014 |
| Backhealth Limited | Health & social care | 2014 |
| Badthesda Games Ltd | Information & communication | 2024 |
| Bagshot LDR Limited | Wholesale & retail | 2018 |