| Arvan Global Ltd | Information & communication | 2020 |
| ARW 85 Property Ltd | Real estate | 2024 |
| Arwh Storage Ltd | Wholesale & retail | 2018 |
| Arya Barber Colchester Ltd | Other services | 2023 |
| AS Boutiques Limited | Administrative & support | 2013 |
| AS One Pilates Ltd | Other services | 2016 |
| AS Rock Ltd | Hospitality | 2019 |
| AS Room Lofts Ltd | Construction | 2020 |
| ASA Plumbing and Heating (Essex) Ltd | Construction | 2025 |
| ASA Rituals Limited | Wholesale & retail | 2025 |
| Asadul Property Ltd | Real estate | 2024 |
| Asap Consultes Ltd | Administrative & support | 2025 |
| Asar Limited | Public administration | 2008 |
| Asbestos Fixing Point Limited | Professional & scientific | 2024 |
| ASC Events Ltd | Professional & scientific | 2019 |
| Ascent AI Labs Ltd | Information & communication | 2025 |
| Ascevio Limited | Information & communication | 2026 |
| ASG Europe Limited | Wholesale & retail | 2007 |
| ASH Cabs Colchester Ltd | Transport & logistics | 2023 |
| ASH Stone Properties Ltd | Real estate | 2024 |
| ASH Tree Developments Limited | Administrative & support | 2017 |
| Ashbee Estates and Facilities Ltd | Construction | 2018 |
| Ashbee Solutions Ltd | Water & waste | 2018 |
| Ashbee Surveying Ltd | Professional & scientific | 2018 |
| Ashbloo Limited | Professional & scientific | 2006 |
| Ashbys Consulting Limited | Administrative & support | 2017 |
| Ashbys Holdings Limited | Financial services | 2019 |
| Ashbys Property Company Limited | Real estate | 2019 |
| Ashcourt Landscaping and Property Maintenance Ltd | Administrative & support | 2014 |
| Ashford Technologies Limited | Information & communication | 2007 |
| Ashie Solutions Ltd | Construction | 2021 |
| Ashita Limited | Real estate | 2024 |
| Ashland Developments Ltd. | Construction | 2019 |
| Ashlawn Limited | Real estate | 2005 |
| Ashley Clothing Limited | Wholesale & retail | 2010 |
| Ashley Herman Developments (Somerset) Limited | Construction | 2001 |
| Ashley Herman Developments Limited | Construction | 1998 |
| Ashley Jones Ltd | Arts & recreation | 2006 |
| Ashmi Limited | Construction | 2013 |
| Ashmor Maintenance Solutions Limited | Wholesale & retail | 2011 |
| Ashnov Homes Ltd | Real estate | 2024 |
| Ashpark Consultants Limited | Professional & scientific | 2023 |
| Ashrana Limited | Health & social care | 2011 |
| Ashsam Estate Management Ltd | Real estate | 2021 |
| Ashsam Medical Ltd | Health & social care | 2015 |
| Ashurst Holdings Limited | Real estate | 2001 |
| Ashvale Consultancy Ltd | Professional & scientific | 2002 |
| Ashvi Invesments Ltd | Real estate | 2023 |
| Ashward Developments Limited | Other services | 2015 |
| Ashwood Care Ltd | Health & social care | 2022 |
| Ashworth Developments Ltd | Construction | 2015 |
| Ashworth Financial Planning Limited | Financial services | 2013 |
| Ashworth Landscapes Ltd | Administrative & support | 2012 |
| Asif Omar Limited | Information & communication | 2015 |
| Asim Medicos Limited | Health & social care | 2025 |
| Asiyaa Limited | Hospitality | 2023 |
| ASK Neil Ltd | Administrative & support | 2016 |
| ASK US Drain Services Limited | Other services | 2006 |
| Aslan Brothers Limited | Real estate | 2021 |
| ASM Logistics Limited | Transport & logistics | 2004 |
| ASM Reactive Scaffold Solutions Ltd | Construction | 2020 |
| ASM Recruitment Ltd | Administrative & support | 2013 |
| ASM Scaffold Solutions Limited | Construction | 2015 |
| Asma's Beauty HUT Ltd | Other services | 2018 |
| Asmuns Consulting Ltd | Professional & scientific | 2019 |
| ASN Assertive Outreach and Consultancy Limited | Administrative & support | 2019 |
| Asonaroh Limited | Health & social care | 2019 |
| Aspect Composites Ltd | Manufacturing | 2026 |
| Aspect Mews Residents Management Company Limited | Real estate | 2015 |
| Aspects Academy Ltd | Education | 2024 |
| Aspects Internet Access Limited | Professional & scientific | 1996 |
| Aspects of Beauty (Colchester) Limited | Other services | 2005 |
| Aspects Residents Company Limited | Households | 2002 |
| Aspectz Limited | Administrative & support | 2000 |
| Aspen Crown Solicitors Limited | Professional & scientific | 2019 |
| Aspen House Holdings Limited | Real estate | 2020 |
| Aspire Colours Ltd | Professional & scientific | 2020 |
| Aspire Construction & Property Limited | Professional & scientific | 2015 |
| Aspire Media Group Investments Ltd | Arts & recreation | 2009 |
| Aspire Media Group Limited | Professional & scientific | 2000 |
| Aspire Media Group Maintenance Services Ltd | Households | 2019 |
| Aspire Media Group Property Services Limited | Real estate | 2012 |
| Aspire Media Group Shared Services Limited | Extraterritorial | 2009 |
| Aspire Models Management Ltd | Administrative & support | 2022 |
| Aspire Projects Limited | Construction | 2019 |
| Aspire Property & Renovation Ltd | Real estate | 2017 |
| Aspire Property Maintenance (UK) Ltd | Real estate | 2011 |
| Aspire Sports and Education Limited | Education | 2024 |
| Aspire Sports Tech. Ltd. | Administrative & support | 2009 |
| Aspiring Lawyers Limited | Administrative & support | 2013 |
| Aspmr Ltd | Other services | 2020 |
| ASQ Medical Ltd | Health & social care | 2022 |
| Asqa Solutions Ltd | Information & communication | 2025 |
| Asrk Holdings Ltd | Financial services | 2024 |
| Assat Global Ltd | Wholesale & retail | 2023 |
| Assay Test Ltd | Wholesale & retail | 2018 |
| Assembly Direct Mail Limited | Transport & logistics | 2004 |
| Assembuild Group Limited | Financial services | 2020 |
| Assembuild Midco Limited | Financial services | 2021 |
| Assembuild Topco Limited | Financial services | 2021 |