| 11MST Ltd | Construction | 2020 |
| 132 Hillsborough Road Management Company Limited | Households | 2025 |
| 1880 Video Productions C.I.C. | Professional & scientific | 2018 |
| 1ST Call Plumbing Limited | Other services | 2017 |
| 1ST for Properties Ltd | Real estate | 2023 |
| 24/7 Immaculate Cleaning Limited | Administrative & support | 2024 |
| 24H Home Express Deliveries Limited | Transport & logistics | 2018 |
| 2B:CREATIVE (N.I.) Ltd | Professional & scientific | 2002 |
| 3 Peaks Recruitment Limited | Professional & scientific | 2026 |
| 365 Beauty & Services Limited | Other services | 2025 |
| 365 Beauty Ltd | Other services | 2025 |
| 3D Group N Ireland Ltd | Manufacturing | 2024 |
| 3NE Ltd | Professional & scientific | 2015 |
| 3SB Group Ltd. | Construction | 2017 |
| 4 Corners Sign Print & Display Limited | Manufacturing | 2015 |
| 45/50 Limited | Other services | 2019 |
| 4DIAMONDS Ltd | Hospitality | 2022 |
| 4GOODFOOD Limited | Wholesale & retail | 2017 |
| 79 Orion Star Holding Limited | Financial services | 2025 |
| 80ANTRIMST Ltd | Hospitality | 2024 |
| 865 Cyber Security Limited | Information & communication | 2022 |
| 888HOMES Ltd | Hospitality | 2020 |
| A 1 Concrete Limited | Manufacturing | 2002 |
| A a Pegasus NET Trading Limited | Wholesale & retail | 2025 |
| A C 4 Haulage Ltd | Transport & logistics | 2016 |
| A C Electrics N.I. Ltd | Construction | 2025 |
| A H Assist Ltd | Other services | 2023 |
| A&W Residential Ltd | Real estate | 2024 |
| A.& S. Donaldson (Northern Ireland) Limited | Wholesale & retail | 1973 |
| A.C. Automotive Services Ltd | Wholesale & retail | 2024 |
| A.E.C. Properties Ltd | Real estate | 2016 |
| A.S.A. Merchandising (N.I.) Ltd | Administrative & support | 1999 |
| A.W. Ennis (N.I.) Limited | Extraterritorial | 1995 |
| A1 Digital Marketing Ltd | Information & communication | 2025 |
| A1 Marsden Recovery Specialists Limited | Professional & scientific | 2013 |
| AA Restaurant Ltd | Hospitality | 2018 |
| AB Nationality Ltd | Administrative & support | 2025 |
| Ab&E Group Limited | Real estate | 2021 |
| ABA Business Group Limited | Health & social care | 2017 |
| Abbey Label Systems Limited | Manufacturing | 2018 |
| Abco Divers Limited | Construction | 1998 |
| Abco Marine Services Ltd | Construction | 2020 |
| Abcord Building Services Limited | Construction | 1986 |
| Abcord Holdco Limited | Financial services | 2024 |
| Abernethy Thallon Ltd | Administrative & support | 2016 |
| ABO Energy Northern Ireland Ltd | Construction | 2010 |
| Abouharb Holdings Ltd | Financial services | 2026 |
| Abouharb Ltd | Health & social care | 2011 |
| ABR Trading Limited | Hospitality | 2018 |
| AC (UK) Limited | | 2005 |
| AC Connects Consultancy Limited | Administrative & support | 2018 |
| AC Rentaplant Limited | Administrative & support | 2014 |
| Accident Hub NI Ltd | Wholesale & retail | 2023 |
| Ace Drains (N.I.) Ltd | Water & waste | 2022 |
| Aces Jewellers Limited | Wholesale & retail | 2014 |
| Acpinky Ltd | Wholesale & retail | 2026 |
| ACR Logistics UK Limited | | 1996 |
| Active Dansa Ltd | Arts & recreation | 2018 |
| Activityni Ltd | Education | 2021 |
| Actonian Consultancy Ltd | Professional & scientific | 2023 |
| Ad-Vance Engineering (Lisburn) Ltd | Professional & scientific | 2012 |
| Adair Family Discretionary Trust Limited | Other services | 2018 |
| Adam Consulting Limited | Real estate | 2019 |
| Adamos Enterprises LP | | 2017 |
| Adaptiv Governance & Risk Limited | Professional & scientific | 2026 |
| Adas Calibration Centre Ltd | Wholesale & retail | 2021 |
| Adas Driver Solutions Ltd | Wholesale & retail | 2020 |
| Adatur Ltd | Hospitality | 2022 |
| Adavion Ltd | Manufacturing | 2020 |
| Adbugs Limited | Professional & scientific | 2005 |
| Adcrete Limited | Wholesale & retail | 2016 |
| Adgey Awnings and Shutters Ltd | Manufacturing | 2015 |
| Admitt Ltd | Professional & scientific | 2025 |
| Advance Business Management LLP | | 2017 |
| Advance Embryology Solutions Ltd | Professional & scientific | 2021 |
| Advance Veterinary Care Ltd | Professional & scientific | 2010 |
| Advanced Care (NI) Ltd | Health & social care | 2012 |
| Advanced Marketing (NI) Ltd | Wholesale & retail | 2007 |
| Advertlab Ltd | Information & communication | 2022 |
| Aethergy Ltd | Professional & scientific | 2020 |
| AFF Solo Warrior LP | | 2020 |
| Affect Ltd | Manufacturing | 2020 |
| Africa Bulk LP | | 2024 |
| Africa Christian Textbooks (Acts) International C.I.C. | Other services | 2023 |
| Afterglass Group Ltd | Hospitality | 2026 |
| AGL (Belfast) Limited | Transport & logistics | 2017 |
| Agota International Ltd | Wholesale & retail | 2020 |
| AGR Global Limited | Financial services | 2026 |
| Agra DIA International Manpower Services Limited | Administrative & support | 2025 |
| Agri and Garden Ltd | Extraterritorial | 2013 |
| Agri-Temps NI Limited | Administrative & support | 2024 |
| AHM Developments Limited | Real estate | 2004 |
| Air Consulting Global Limited | Professional & scientific | 2014 |
| Air N.I Ltd | Professional & scientific | 2022 |
| Airfibre Limited | Information & communication | 2014 |
| AJ Print & Embroidery Limited | Manufacturing | 2023 |
| Aj.Fowler Holdings Ltd | Financial services | 2026 |
| Aj.Fowler Properties Ltd | Real estate | 2025 |
| Ajjor Ltd | Wholesale & retail | 2020 |
| AJM Optical Management Ltd | Health & social care | 2018 |