| 1 Stop Safety 2015 Ltd | Professional & scientific | 2019 |
| 360 Fitout Ltd | Construction | 2025 |
| 360 Leisure Limited | Real estate | 2016 |
| 3DFA Carpentry & Construction Ltd | Construction | 2025 |
| 4 Energy Solutions Limited | Professional & scientific | 2019 |
| 4C Coffee House and Kitchen Ltd | Hospitality | 2020 |
| 7 Oaks Green Management Ltd | Households | 2017 |
| 8 Castleblayney Road Ltd | Construction | 2024 |
| A & a Leeman Contracts Ltd | Construction | 2015 |
| A & E Crozier Ltd | Agriculture & fishing | 2017 |
| A & J Plumbing Services Ltd | Construction | 2019 |
| A & M Trailers Ltd | Manufacturing | 2008 |
| A W Control Systems Ltd | Manufacturing | 2007 |
| A Wilson Contracts Ltd | Construction | 2010 |
| A&A Crawford Ltd | Real estate | 2023 |
| A&M Commercials Group Limited | Wholesale & retail | 2021 |
| A&M Commercials Limited | Wholesale & retail | 1999 |
| A&M Logistics Ireland Ltd | Transport & logistics | 2011 |
| A-One Control Holdings Ltd | Financial services | 2025 |
| A-One Control Properties Ltd | Real estate | 2025 |
| A.T. and T. Rentals Limited | Other services | 1988 |
| A1 Construction (NI) Ltd | Construction | 2014 |
| A:Mac Aesthetics Ltd | Health & social care | 2019 |
| AAM Management and Lettings Limited | Real estate | 2023 |
| Abacus Inns Ltd | Hospitality | 2013 |
| Abbey Electrical (Armagh) Ltd | Construction | 2026 |
| Abbey Financial Services (N.I.) Limited | Financial services | 2008 |
| Abbey Lane Properties Armagh Ltd | Real estate | 2022 |
| Abdam Trading Limited | Financial services | 2019 |
| Abelo (NI) Ltd | Wholesale & retail | 2025 |
| ABM Motor Group Ltd | Wholesale & retail | 2019 |
| Abme Drive Thru Limited | Hospitality | 2024 |
| Abme Holdings Ltd | Financial services | 2022 |
| Abme Ltd | Professional & scientific | 2022 |
| Abode Living Solutions Limited | Construction | 2021 |
| Abraham Installations Limited | Construction | 2015 |
| AC Fuels Ltd | Wholesale & retail | 2026 |
| Acdc Signs Ltd | Manufacturing | 2014 |
| ACF Mechanical Ltd | Construction | 2022 |
| ACS - Abbey Contract Services Limited | Construction | 2024 |
| Acur Electrical Ltd | Construction | 2021 |
| Acur Ltd | Construction | 2011 |
| AD Electricity Ltd | Energy | 2017 |
| Addg Properties Limited | Real estate | 2021 |
| ADH Transport Ltd | Transport & logistics | 2023 |
| ADL Tile & Stone Contracts Ltd | Wholesale & retail | 2024 |
| Adrian & Maura Mcnally Ltd | Wholesale & retail | 2005 |
| Advance Financial Services (NI) Ltd | Financial services | 2013 |
| Advanced Building Consultants Limited | Professional & scientific | 2019 |
| Advanced Ceramic Engineering Ltd | Manufacturing | 2012 |
| Advanced Flooring Systems Ltd | Construction | 2021 |
| AFS Freight Ltd | Transport & logistics | 2019 |
| Agas Plumbing Limited | Construction | 2023 |
| Aghavilly Farms Ltd | Agriculture & fishing | 2022 |
| Agquip Machinery Limited | Manufacturing | 2024 |
| Agri Competitions Ltd | Arts & recreation | 2020 |
| Agway NI Ltd | Agriculture & fishing | 2025 |
| AIC Energy Limited | Energy | 2021 |
| AIC Environmental Engineering Ltd | Financial services | 2024 |
| AIC Group Limited | Manufacturing | 2016 |
| AIC Holdings Limited | Manufacturing | 2021 |
| AIC Pensions & Investments Ltd | Financial services | 2018 |
| AIC Waste Management Limited | Water & waste | 2020 |
| Aidan Mccrystal Assets Limited | Administrative & support | 2012 |
| Aidan Mccrystal Properties Limited | Real estate | 2012 |
| AIG Nomad Motors Limited | Wholesale & retail | 2025 |
| Airbnb Solutions Ltd | Real estate | 2024 |
| Alan Buckley Coaching Limited | Health & social care | 2024 |
| Alan Simpson Refrigeration, Air Conditioning & Electrical Ltd | Manufacturing | 2008 |
| Alcm Limited | Professional & scientific | 2018 |
| Alexanders of Markethill (Furnishings) Limited | Wholesale & retail | 2003 |
| Alive Environmental Ltd | Professional & scientific | 2019 |
| ALL Nations Church Belfast | Other services | 2025 |
| Allans IP Limited | Financial services | 2026 |
| Allen Electrical Contracts Ltd | Construction | 2021 |
| Alles Ltd | Other services | 2019 |
| Allied Cbam Limited | Professional & scientific | 2025 |
| Allied Group Limited | Other services | 2017 |
| Allied Property Rentals Ltd | Real estate | 2025 |
| Alora Rejuvenation Limited | Health & social care | 2021 |
| Alper Limited | Wholesale & retail | 2023 |
| Alvin Wallace Transport Limited | Transport & logistics | 2020 |
| Amber Arrow Holding Company Limited | Financial services | 2021 |
| Amca Properties Limited | Real estate | 2022 |
| AMN Civils and Construction Ltd | Construction | 2019 |
| AMN Murray Properties Limited | Real estate | 2022 |
| AMP Industrial Services Limited | Construction | 2023 |
| Amrak Management Services Ltd | Professional & scientific | 2022 |
| AN Gael Whiskey Ltd | Manufacturing | 2022 |
| Ancaeo Holdings Ltd | Professional & scientific | 2026 |
| Andrew Murphy Transport Ltd | Transport & logistics | 2016 |
| Annagora Enterprises Limited | Professional & scientific | 2019 |
| Annahill Livestock Ltd | Agriculture & fishing | 2024 |
| Annahugh Haulage Ltd | Transport & logistics | 2021 |
| Annareagh Ltd | Professional & scientific | 2022 |
| Annareagh Properties Limited | Real estate | 2025 |
| Annvale Construction (Armagh) Ltd | Construction | 2017 |
| Annvale Construction (Contracts) Ltd | Construction | 2025 |
| Annvale PVC Ltd | Manufacturing | 2003 |
| Annvale Windows & Doors Limited | Construction | 2024 |