| Apss Group Limited | Financial services | 2024 |
| Aptica Ltd | Information & communication | 2026 |
| APW Auto Ltd | Wholesale & retail | 2023 |
| Aqua Energy Saving Systems Ltd | Manufacturing | 2017 |
| Aqua Stars Swim School Limited | Arts & recreation | 2018 |
| Aqua Stars Training Ltd | Education | 2025 |
| Aqua-Response Limited | Manufacturing | 2006 |
| Aqualibrium UK Limited | Wholesale & retail | 2002 |
| Aquashield Products UK Ltd | Wholesale & retail | 2020 |
| Aquashii Media Ltd | Information & communication | 2014 |
| Aquatronics Ltd | Manufacturing | 2017 |
| Aquegloves Limited | Administrative & support | 2025 |
| Aquilo Estates Limited | Real estate | 2010 |
| AR Auto Dynamics Ltd | Wholesale & retail | 2025 |
| Arabic Library Ltd | Wholesale & retail | 2024 |
| Arable Alliance Limited | Agriculture & fishing | 2009 |
| Araxo Group Ltd | Wholesale & retail | 2012 |
| Arboretum Psychotherapy Ltd | Health & social care | 2023 |
| Arborez Ltd | Agriculture & fishing | 2019 |
| Arborglyph Tree Services Ltd | Agriculture & fishing | 2020 |
| Arbour Construction Ltd | Construction | 2025 |
| ARC Broker Services Limited | Financial services | 2018 |
| Arcanum Academy Limited | Education | 2025 |
| Arcanum Copy Limited | Professional & scientific | 2025 |
| Arch Leisure Buildings Ltd | Real estate | 2020 |
| Arch Scaffolding (Lincs) Limited | Construction | 2024 |
| Archer Assist Ltd | Information & communication | 2021 |
| Archer Ecology Ltd | Professional & scientific | 2021 |
| Archer Road Apartments Branston RTM Company Ltd | Households | 2019 |
| Archerxi Ltd | Wholesale & retail | 2022 |
| Archie Leisure Ltd | Wholesale & retail | 2023 |
| Archive Luxury Limited | Wholesale & retail | 2025 |
| Archway Catering Ltd | Hospitality | 2025 |
| Arco Security Ltd | Administrative & support | 2019 |
| Ardor Eyewear Limited | Wholesale & retail | 2023 |
| Ardual Ltd | Health & social care | 2016 |
| ARE YOU Ltd | Information & communication | 2019 |
| Ares Speed Ltd | Transport & logistics | 2023 |
| ARG Lincoln Limited | Real estate | 2018 |
| Argentum Consultants Limited | Professional & scientific | 2016 |
| Argus Ventures Holdings Limited | Financial services | 2025 |
| Argus Ventures Limited | Information & communication | 2019 |
| Aria Learning Solutions Ltd | Professional & scientific | 2017 |
| Arisa Properties Limited | Real estate | 2025 |
| Arise Church Lincoln | Other services | 2001 |
| Ariva Properties Limited | Real estate | 2020 |
| ARK Confined Space Training Ltd | Education | 2026 |
| Arleen Wild Limited | Arts & recreation | 2005 |
| ARM Poultry Limited | Agriculture & fishing | 2016 |
| Arma Drylining Ltd | Construction | 2019 |
| Arma Property Consultants Ltd | Real estate | 2025 |
| Arma Property Holdings Ltd | Real estate | 2025 |
| Arma Roofing and Building Ltd | Construction | 2022 |
| Armstrong Joinery Ltd | Construction | 2024 |
| Arnatt Consulting Ltd | Information & communication | 2025 |
| Arnold Anaesthesia Ltd | Health & social care | 2019 |
| Aroldo Ltd | Agriculture & fishing | 2019 |
| Aroqua Ltd. | Professional & scientific | 1999 |
| ARP Solutions (SZC) Ltd | Hospitality | 2025 |
| Arrazzaq Consultancy Limited | Information & communication | 2014 |
| Arris Engineering Limited | Professional & scientific | 2026 |
| Arrow Delivery Services Ltd | Transport & logistics | 2017 |
| Arsf Limited | Health & social care | 2013 |
| Arslan Ashraf UK Limited | Wholesale & retail | 2026 |
| Art Pizza Ltd | Hospitality | 2026 |
| Art Reaction Limited | Professional & scientific | 2013 |
| Artco Holding Ltd | Financial services | 2021 |
| Artech Designs Limited | Professional & scientific | 2014 |
| Artemis Care Limited | Health & social care | 2017 |
| Artgm Ltd | Other services | 2019 |
| Arthauss Furniture Ltd | Wholesale & retail | 2015 |
| Artimus Ltd | Construction | 2009 |
| Artradex Ltd | Information & communication | 2014 |
| Artur Packowski Building Services Ltd | Construction | 2021 |
| Artur Wrobel Ltd | Transport & logistics | 2014 |
| Arturus Group Ltd | Financial services | 2025 |
| Arturus Property Management Ltd | Hospitality | 2025 |
| ARV (PVT) Limited | Wholesale & retail | 2026 |
| Arviteni Ltd | Information & communication | 2019 |
| Arxis Ltd | Real estate | 2024 |
| AS Radiology Ltd | Health & social care | 2012 |
| ASA Real Estate Holdings Ltd | Real estate | 2026 |
| Asali Designs Ltd | Wholesale & retail | 2020 |
| Asap Socks Ltd | Wholesale & retail | 2024 |
| Asbesafe Environmental Limited | Water & waste | 2016 |
| Asbesafe Limited | Water & waste | 2018 |
| Asbestos Compliance Management Services Limited | Professional & scientific | 2010 |
| Asbestos in Homes Limited | Extraterritorial | 2010 |
| ASC Metals Lincoln Trustees Limited | Administrative & support | 2025 |
| Ascari Limited | Information & communication | 2003 |
| Ascension Analysis Services Limited | Professional & scientific | 2022 |
| Ascensus Communications C.I.C. | Information & communication | 2023 |
| Ascensus Media Ltd | Financial services | 2016 |
| Ascensus Property LLP | | 2016 |
| ASF 20 Ltd | Professional & scientific | 2020 |
| ASF Installations Ltd | Construction | 2018 |
| ASH Cottage Animal Care Ltd | Other services | 2022 |
| ASH Country Homes Ltd | Construction | 2020 |
| ASH Dowie Design Ltd | Professional & scientific | 2019 |
| ASH Grove (Sudbrooke) Management Company Limited | Households | 2018 |