| "Cnoc NA RI" Developments Limited | Construction | 2006 |
| 'THE Causeway Craic' Ltd | Extraterritorial | 2022 |
| 125 Dairy Ltd | Agriculture & fishing | 2024 |
| 145 Investments Ltd | Real estate | 2024 |
| 15 Main Street Ltd | Hospitality | 2022 |
| 2050 Technologies Ltd | Construction | 2021 |
| 246 Self Container Storage Ltd | Transport & logistics | 2017 |
| 2B Engineering Ltd | Manufacturing | 2015 |
| 39K9 Ltd | Wholesale & retail | 2026 |
| 3TPOWER Ltd | Energy | 2013 |
| 42 Digital Ltd | Professional & scientific | 2017 |
| 4SM (N.I.) Limited | Information & communication | 2013 |
| 9TH Avenue Limited | Hospitality | 2013 |
| 9TH E Limited | Hospitality | 2018 |
| A & B Contracts (N.I.) Limited | Construction | 1998 |
| A & B Fire Equipment Ltd | Manufacturing | 2011 |
| A & C Components Ltd | Wholesale & retail | 2009 |
| A Burnside | Professional & scientific | 2015 |
| A W Contracts Ltd | Construction | 2014 |
| A&M Clarke Ltd | Real estate | 2026 |
| A. G. O'Neill Limited | Real estate | 1984 |
| A. R. D. Pubs Ltd | Hospitality | 2018 |
| A1 Distro Limited | Wholesale & retail | 2025 |
| A4 Accident & Repair Centre Ltd | Wholesale & retail | 2012 |
| A5 Autoshop Ltd | Wholesale & retail | 2021 |
| A5 Diner Ltd | Hospitality | 2023 |
| AA Specialist Wholesalers Limited | Water & waste | 2023 |
| Aa-Crete Ltd | Manufacturing | 2014 |
| Aairex Environmental UK Ltd | Manufacturing | 1994 |
| AB Coaching Life & Sport Ltd | Education | 2021 |
| AB Motors & Commercials Ltd | Wholesale & retail | 2014 |
| Abac (NI) Ltd | Extraterritorial | 2008 |
| ABC for PCS Ltd | Wholesale & retail | 2019 |
| Abcl Developments Ltd | Construction | 2018 |
| ABG Electrical & Security Ltd | Construction | 2021 |
| Absolute Catering Supplies Ltd | Wholesale & retail | 2022 |
| ACA a Limited | Professional & scientific | 2012 |
| ACA Architecture Limited | Professional & scientific | 2017 |
| ACA Construction Services (NI) Limited | Administrative & support | 2017 |
| Accent AI Technologies Ltd | Information & communication | 2025 |
| Ace Registrations Ltd | Wholesale & retail | 2020 |
| Ace Telecoms Ltd | Information & communication | 2017 |
| Acmeic Holdings Ltd | Professional & scientific | 2023 |
| ACR Direct Care Ltd | Health & social care | 2023 |
| Acres Consultancy Services Ltd | Professional & scientific | 2015 |
| ACS Civils Ltd | Construction | 2015 |
| Adam International Trade Ltd | Wholesale & retail | 2018 |
| Adams & Pollock Funeral Directors Limited | Other services | 2019 |
| Adhoc Maintenance Solutions Ltd | Professional & scientific | 2024 |
| Adman Civil Projects Limited | Construction | 2007 |
| Adman Construction Limited | Construction | 2020 |
| Adman Group Limited | Financial services | 2017 |
| Adman Plant Services Limited | Administrative & support | 2013 |
| Adman Services Limited | Construction | 2017 |
| Admanottjv Limited | Construction | 2023 |
| Admire Haircare Ltd | Wholesale & retail | 2025 |
| Adrian Devine Contracts Ltd | Construction | 2014 |
| Adrian Mccaffrey Trading Co Ltd | Manufacturing | 2013 |
| Adrian Pollock Cars Ltd | Wholesale & retail | 2020 |
| Advanced Cabling Contractors Ltd | Construction | 2019 |
| Advanced Concrete & Formwork Ltd | Construction | 2010 |
| Advanced Contracts Limited | Construction | 2016 |
| Advanced Engineering Group Ltd | Construction | 2013 |
| Advanced Holdings (N.I.) Limited | Financial services | 2024 |
| Advanced Plant Hire Ltd | Professional & scientific | 2022 |
| AER DRY Ltd | Manufacturing | 2018 |
| AER Fhorsa Limited | Energy | 2016 |
| Aerial Gymnastics Centre Limited | Arts & recreation | 2022 |
| Aetp Trustee Company Limited | Extraterritorial | 2018 |
| AFN Drainage Ltd | Construction | 2016 |
| AG Capital Ltd | Professional & scientific | 2019 |
| Age-On C.I.C. | Health & social care | 2015 |
| AGG Autos Ltd | Wholesale & retail | 2019 |
| Aghadaragh Holdings Ltd | Financial services | 2021 |
| Agharonan Farms Ltd | Agriculture & fishing | 2025 |
| Agri Contracts Limited | Agriculture & fishing | 2013 |
| Agri, Plant and Commercial Finance Limited | Financial services | 2016 |
| Agri-Power (Donegal) Ltd | Wholesale & retail | 2014 |
| AI Advanced Limited | Information & communication | 2023 |
| Aiden Kelly Commercials Ltd | Wholesale & retail | 2023 |
| Aiken Contracts Limited | Construction | 2026 |
| Ainsford Ltd | Information & communication | 2014 |
| Air Flow Innovations Ltd | Construction | 2024 |
| Aisen Aisen Ltd | Wholesale & retail | 2025 |
| AJ Smyth Properties Ltd | Real estate | 2024 |
| AJM Electrical Limited | Agriculture & fishing | 2011 |
| AJS Company Holdings Ltd | Financial services | 2014 |
| AJS Event Catering Limited | Hospitality | 2010 |
| AJS Promotions Ltd | Administrative & support | 2002 |
| AJS Shops Ltd | Wholesale & retail | 2020 |
| Alexander (Plant) Ltd | Administrative & support | 2013 |
| ALG Biogas Ltd | Energy | 2012 |
| ALG Farms Ltd | Agriculture & fishing | 2020 |
| Aligned Health Care Ltd | Health & social care | 2013 |
| ALL Beverage Services Ltd | Manufacturing | 2007 |
| ALL Business Advice Centre Ltd | Extraterritorial | 2008 |
| ALL Interiors (NI) Ltd | Wholesale & retail | 2014 |
| Alora Home Ltd | Wholesale & retail | 2021 |
| Alpha Flow Screeds Limited | Construction | 2015 |
| Alta Autos Limited | Wholesale & retail | 2018 |