| 10X Publishing Ltd | Information & communication | 2021 |
| 14KR Ltd | Professional & scientific | 2024 |
| 160B Consulting Ltd | Professional & scientific | 2017 |
| 2 UR DOR Ltd | Extraterritorial | 2005 |
| 23 Beverage Edge Limited | Wholesale & retail | 2025 |
| 24/7 Trailer Services Ltd | Administrative & support | 2013 |
| 25 Glandore Avenue Management Company Limited | Households | 2023 |
| 26 Joy Avenue Children's Club Ltd | Health & social care | 2017 |
| 2D Holdings Ltd | Real estate | 2023 |
| 3 Entertainment Sunderland Ltd | Hospitality | 2019 |
| 33 Green Limited | Financial services | 2019 |
| 3CG Consulting Limited | Professional & scientific | 2022 |
| 3D FM Ireland Ltd | Other services | 2025 |
| 4M Integrated Control Solutions Limited | Professional & scientific | 2026 |
| 54 Degrees Design Ltd | Professional & scientific | 2016 |
| 9T3 Design Limited | Information & communication | 2021 |
| A a Hydraulics Limited | Manufacturing | 2006 |
| A Gormley Ltd | Construction | 2019 |
| A J Wylie Machinery LLP | | 2025 |
| A Mccrory & Co Ltd | Professional & scientific | 2022 |
| A Timely Snow Limited | Wholesale & retail | 2025 |
| A&J Burrows (NI) Limited | Real estate | 2016 |
| A-Gen (NI) Ltd | Manufacturing | 2011 |
| A-One Shuttering Limited | Administrative & support | 2002 |
| A-X Manufacturing Ltd | Manufacturing | 2019 |
| A1 Electrical & Lighting Ltd | Construction | 2025 |
| AA Star Taxis Ltd | Transport & logistics | 2021 |
| AAM (N.I.) Ltd | Other services | 2010 |
| Aassk Ltd | Health & social care | 2022 |
| AB Lifting & Testing Services Ltd | Manufacturing | 2019 |
| Abbey Private Nursing Home Ltd | Health & social care | 2011 |
| ABM Parts Limited | Wholesale & retail | 2024 |
| Abmb Motors Ltd | Wholesale & retail | 2024 |
| Abode Ireland Ltd | Manufacturing | 2022 |
| Absolute Printing Ltd | Manufacturing | 2009 |
| Absolute Protection and Wealth Ltd | Financial services | 2017 |
| Accident First Choice Management NI Ltd | Other services | 2019 |
| Ace Animal Aids Ltd | Professional & scientific | 2008 |
| Ace Coaches Ltd | Transport & logistics | 2024 |
| Ace International Group Limited | Wholesale & retail | 2024 |
| Acer Electrical Limited | Construction | 2018 |
| Achieve Academy Ltd | Education | 2025 |
| Acker Developments Limited | Financial services | 1994 |
| Acrow Formwork (N.I.) Ltd | Wholesale & retail | 2003 |
| Acrow Formwork Ltd | Wholesale & retail | 2017 |
| Acrow Rental (NI) Ltd | Administrative & support | 2012 |
| Active Maintenance Solutions Limited | Construction | 1999 |
| Acute Engineering Surveys Limited | Professional & scientific | 2005 |
| Adaco on the Go Ltd | Hospitality | 2025 |
| Adair Systems and Software Ltd | Professional & scientific | 2018 |
| Adapt Global Solutions Ltd | Wholesale & retail | 2020 |
| Adapt GSE Ltd | Wholesale & retail | 2020 |
| Adeles Apothecary Ltd | Wholesale & retail | 2018 |
| Adon Connect Ltd | Wholesale & retail | 2025 |
| Advance Accounting (NI) Ltd | Professional & scientific | 2014 |
| ADW Agri Services Ltd | Wholesale & retail | 2022 |
| ADY Enterprises Ltd | Financial services | 2021 |
| AEA Financial Services Ltd | Financial services | 2026 |
| Aecentus Limited | Professional & scientific | 2013 |
| Aepp LLP | | 2018 |
| Aerio Biogas Limited | Professional & scientific | 2017 |
| AF Farm Services Limited | Agriculture & fishing | 2010 |
| AG Nutritional Services Ltd | Agriculture & fishing | 2022 |
| Aggregate Recycling Consultants Ltd | Professional & scientific | 2023 |
| Aghareany Limited | Professional & scientific | 2006 |
| Aghh Ltd | Financial services | 2017 |
| Aghla More Limited | Real estate | 2012 |
| Aghlabeg Limited | Financial services | 2023 |
| Agri Business Solutions Ltd | Agriculture & fishing | 2014 |
| Agri Performance Plumbing Ltd | Agriculture & fishing | 2017 |
| Agri Performance Products Ltd | Agriculture & fishing | 2012 |
| Agri-Forage Solutions Ltd | Agriculture & fishing | 2020 |
| Agrispeed Ltd | Manufacturing | 2016 |
| AHC Contracts Limited | Professional & scientific | 2021 |
| AHK Accounting Limited | Professional & scientific | 2014 |
| AHK Developments (NI) Limited | Real estate | 2014 |
| AHK Investments (NI) Limited | Real estate | 2012 |
| Aidan Quinn Solicitors Ltd | Extraterritorial | 2014 |
| Aillefroide Nord LLP | | 2014 |
| Aillefroide SUD LLP | | 2014 |
| Aimaros Ltd | Professional & scientific | 2025 |
| Airductni Ltd | Manufacturing | 2025 |
| AJ Global Trade Ltd | Professional & scientific | 2026 |
| AJC Motorworx Ltd | Wholesale & retail | 2024 |
| AJH Transport (2026) Ltd | Transport & logistics | 2026 |
| Ajsm Healthcare Limited | Health & social care | 2021 |
| AJT Transport Consultancy Ltd | Professional & scientific | 2012 |
| Albert Mews Developments Limited | Construction | 2005 |
| Aleden Contracts UK Ltd | Construction | 2019 |
| ALL Lights OUT Ltd | Extraterritorial | 2024 |
| ALL Vehicle Rentals Ltd | Administrative & support | 2015 |
| Allie Digital CIC | Information & communication | 2024 |
| Ally Holdings Ltd | Real estate | 2020 |
| Almax Trading Co Ltd | Wholesale & retail | 2025 |
| Almond Catering N.I. Ltd | Hospitality | 2017 |
| ALP Farms Limited | Agriculture & fishing | 2013 |
| Alpha Media Group Limited | Information & communication | 2016 |
| Alpha Newspapers Limited | Information & communication | 2005 |
| Alpha Wind Ltd | Construction | 2019 |
| Alskea (Belvoir) Ltd | Construction | 2024 |