| Accurating Limited | Real estate | 2007 |
| Ace Automotive Limited | Wholesale & retail | 2020 |
| Ace Energy Limited | Extraterritorial | 2008 |
| Ace Engineering Services Ltd | Construction | 2025 |
| Ace GAS Limited | Wholesale & retail | 2003 |
| Ace Highways Limited | Transport & logistics | 1975 |
| Ace Motoring Company Ltd | Wholesale & retail | 2025 |
| Ace Recycle Limited | Water & waste | 1992 |
| Acecco Ltd | Health & social care | 2026 |
| Achieve With SAT Ltd | Education | 2024 |
| Achievement in Mind Ltd. | Arts & recreation | 2013 |
| ACJ Detailing Limited | Construction | 2016 |
| Ackroyds (Accountancy & Taxation Services) Ltd | Professional & scientific | 2012 |
| Acorn Ryley Ltd | Wholesale & retail | 2025 |
| Acornity Ltd | Extraterritorial | 2025 |
| ACS Commercial Roofing Ltd | Professional & scientific | 2023 |
| ACS Inventories Ltd | Other services | 2012 |
| Activ Consulting Group Limited | Administrative & support | 2011 |
| Activate Accident Repair Group Limited | Wholesale & retail | 2019 |
| Activate Collision Solutions Limited | Wholesale & retail | 2020 |
| Activate Group Holdings Limited | Financial services | 2023 |
| Activate Group Limited | Financial services | 2015 |
| Activate Parts Limited | Wholesale & retail | 2008 |
| Active Care Chiropractic Limited | Health & social care | 2009 |
| Active Heritage Ltd | Education | 2011 |
| Activlux Ltd | Wholesale & retail | 2025 |
| Acuwave Limited | Financial services | 2017 |
| Adaa Properties Ltd | Real estate | 2026 |
| Adam Glassford Limited | Health & social care | 2013 |
| Adam I Joinery Ltd | Construction | 2023 |
| Adam Kenny Physiotherapy Ltd | Health & social care | 2020 |
| Adam Privat Hire Ltd | Transport & logistics | 2024 |
| Adam Worsick Joinery Limited | Construction | 2019 |
| Adam's Steak Box Ltd | Hospitality | 2025 |
| Adams Cafe Halifax Limited | Wholesale & retail | 2017 |
| Adamson Commercial Ltd | Professional & scientific | 2022 |
| Adamson Wray Ltd | Financial services | 2024 |
| Adaptis Care Solutions Ltd | Wholesale & retail | 2025 |
| Adbro Limited | Hospitality | 2003 |
| Addison Properties (Halifax) Limited | Construction | 2015 |
| Additions Accountancy Services (Halifax) Ltd | Professional & scientific | 2014 |
| Adele Wills Limited | Professional & scientific | 2012 |
| Aden Fitness & Wellbeing for Women Ltd | Arts & recreation | 2024 |
| Adenium Commodities Ltd | Financial services | 2022 |
| Adept Demolition Ltd | Construction | 2011 |
| Adhd Care Clinic Limited | Health & social care | 2026 |
| Adhd Clinics Ltd | Health & social care | 2020 |
| ADI Business Consultants Limited | Information & communication | 2015 |
| ADI Home Rentals Limited | Real estate | 2024 |
| ADJ Property Services Limited | Construction | 2022 |
| ADK Locum Services Ltd | Professional & scientific | 2012 |
| Adkins Limited | Professional & scientific | 2019 |
| ADL Distro Ltd | Transport & logistics | 2024 |
| ADO Equipment Limited | Wholesale & retail | 2019 |
| ADO PAY Ltd | Administrative & support | 2022 |
| ADO Restoration Limited | Wholesale & retail | 2023 |
| Adora Beds Ltd | Manufacturing | 2019 |
| Adormeh Excel & Care Limited | Health & social care | 2021 |
| Adpr Property Developments Limited | Construction | 2025 |
| ADR Analytics Ltd | Information & communication | 2026 |
| ADS Assets (Yorkshire) Limited | Real estate | 2022 |
| ADS Consultancy Services (Yorkshire) Ltd | Professional & scientific | 2018 |
| Adult Learning Group Ltd | Education | 2024 |
| Advanced Aesthetics of London Ltd | Other services | 2013 |
| Advanced Auto Services (Halifax) Limited | Wholesale & retail | 2003 |
| Advanced Building (NW) Ltd | Construction | 2005 |
| Advanced Entrance Systems Ltd | Professional & scientific | 2014 |
| Advanced GAS Yorkshire Limited | Construction | 2013 |
| Advanced Properties (NW) Ltd | Real estate | 2017 |
| Advanced Solutions (GB) Ltd | Construction | 2013 |
| Advanced Vending Solutions Ltd | Hospitality | 2006 |
| Advancement of Community Empowerment C.I.C. | Administrative & support | 2013 |
| Advent Corporate Finance Limited | Financial services | 2004 |
| Adventure Training Limited | Arts & recreation | 1989 |
| Advocate Garage Limited | | 2022 |
| AEB Lettings Ltd | Real estate | 2024 |
| Aebell Limited | Professional & scientific | 2010 |
| Aefm International Limited | Professional & scientific | 2026 |
| Aegle Abode Limited | Real estate | 2018 |
| AEK Properties Ltd | Real estate | 2022 |
| Aeronox Solutions Ltd | Administrative & support | 2025 |
| Aesthetics by Abbie Ltd | Other services | 2023 |
| Aetheris.Ai Ltd | Manufacturing | 2026 |
| AEW Merchandise Limited | Administrative & support | 2019 |
| Ae’Ko Atelier Limited | Wholesale & retail | 2025 |
| AF Wellness Solutions Limited | Arts & recreation | 2025 |
| Affordable Rentals (Residential) Ltd | Real estate | 2019 |
| Aficion Ltd | Information & communication | 2011 |
| Afiyah Wellbeing Ltd | Health & social care | 2023 |
| African Tourism Showcase Group Limited | Administrative & support | 2023 |
| Afrisec Ltd | Professional & scientific | 2023 |
| AFT Healthcare Ltd | Health & social care | 2021 |
| After Accident Care Team Limited | Wholesale & retail | 2006 |
| AG Bars Ltd | Hospitality | 2024 |
| AG Joinery & Building Maintenance Ltd | Manufacturing | 2022 |
| Agbisit Acquisitions Ltd | Professional & scientific | 2025 |
| AGE UK Calderdale & Kirklees | Health & social care | 2004 |
| AGP Project Services Ltd | Professional & scientific | 2025 |
| Agsj Enterprises Ltd | Real estate | 2021 |
| AH Tradeworld Ltd | Wholesale & retail | 2023 |