| Storely Ltd | Wholesale & retail | 2026 |
| Stran-Wiches Limited | Hospitality | 2022 |
| Strawhill Estate Spirits Company Ltd | Manufacturing | 2017 |
| STRIVE2THRIVE (N.I.) Ltd | Health & social care | 2022 |
| Stroove Ltd | Real estate | 2024 |
| Stuart Best & Associates Limited | Health & social care | 2011 |
| Student Comps Ltd | Wholesale & retail | 2021 |
| Studio 7 Entertainment Limited | Information & communication | 2024 |
| Studio Affect Ltd | Professional & scientific | 2024 |
| Studyseed Publishing Ltd | Information & communication | 2016 |
| Style Rack Ltd | Wholesale & retail | 2017 |
| Sublimating Limited | Hospitality | 2025 |
| Sullivans Engineering Limited | Professional & scientific | 2021 |
| Sunbeds Raze Ltd | Other services | 2025 |
| Sunnyside Holdco NI Limited | Financial services | 2025 |
| Sunnyside Nurseries Limited | Agriculture & fishing | 2018 |
| Sunrise Autos Garage Ltd | Wholesale & retail | 2025 |
| Superior Construction (IRE) Limited | Construction | 2024 |
| Superior Facilities Management Ltd | Real estate | 2010 |
| Superstars Daycare & Afterschool Ltd | Health & social care | 2021 |
| Supply Chain Distribution Services Limited | Professional & scientific | 2021 |
| Sure Safe Boilers Ltd | Construction | 2023 |
| Surehomeni Ltd | Construction | 2026 |
| Surrey Estates Limited | Real estate | 1989 |
| Sushi Astra NI Ltd | Hospitality | 2025 |
| Sustain First AID Limited | Professional & scientific | 2008 |
| Sustar Developments Ltd | Construction | 2020 |
| Sustar Developments NO2 Ltd | Construction | 2025 |
| Sutherland Mitchell Limited | Professional & scientific | 2010 |
| SVR Go Holdings Ltd | Wholesale & retail | 2020 |
| SVR Go Ltd | Administrative & support | 2022 |
| SWB Car Centre Limited | Wholesale & retail | 2025 |
| Symbiosis Community Ltd | Wholesale & retail | 2025 |
| Synora Limited | Information & communication | 2025 |
| Synthesis in Praxis Ltd | Professional & scientific | 2023 |
| T & J Auto Centre Ltd | Wholesale & retail | 2024 |
| T & S Properties (NI) Ltd | Real estate | 2011 |
| T Duke Ltd | Professional & scientific | 2019 |
| T MC Alinden & Co Limited | Construction | 2014 |
| T Scullion Electrical Ltd | Construction | 2017 |
| T&K Smith Limited | Hospitality | 2022 |
| T-Mac Property Ltd | Real estate | 2025 |
| T-Safe UK Ltd | Wholesale & retail | 2018 |
| T.W. Haffey & Sons Limited | Agriculture & fishing | 1963 |
| T2T Hire & Sales Ltd | Administrative & support | 2024 |
| Table Church | Other services | 2017 |
| Taboo Donuts Ltd | Manufacturing | 2018 |
| Tactical Retreat Ltd | Wholesale & retail | 2019 |
| Taghnevan Sports Limited | Arts & recreation | 2007 |
| Taibhse Holdings Ltd | Financial services | 2023 |
| Talentify Limited | Professional & scientific | 2023 |
| Tall Oaks Enterprises Ltd | Wholesale & retail | 2025 |
| Tall River Lodge Limited | Real estate | 2025 |
| Tamnaghmore Off-Road Centre Ltd | Arts & recreation | 2019 |
| Tamnamore Joinery Ltd | Manufacturing | 2011 |
| Tamnavelton Ltd | Energy | 2017 |
| Tamnyvane Ltd | Construction | 2026 |
| Tandragee Fuels & Oils Limited | Wholesale & retail | 2018 |
| Tankcube Ltd | Manufacturing | 2021 |
| Tanton Solutions Ltd | Information & communication | 2025 |
| Tanzo Limited | Health & social care | 2024 |
| Taranto Holdings Limited | Construction | 2019 |
| Tarnyia Properties Ltd | Households | 2025 |
| Tate Stevenson Architects Limited | Professional & scientific | 2005 |
| Taughlumny Poultry Ltd | Agriculture & fishing | 2012 |
| Taught Media Limited | Information & communication | 2012 |
| Taulbridge Limited | Real estate | 2024 |
| Tavanagh Limited | Real estate | 2016 |
| Taylor Sales & Distribution Ltd | Hospitality | 2007 |
| Taylor Specialist Services Ltd. | Construction | 2024 |
| Taylors Fashion Opticians Ltd | Wholesale & retail | 2014 |
| TBS Labs Ltd | Information & communication | 2026 |
| TC Bedding & Haulage Ltd | Agriculture & fishing | 2019 |
| TC Insulation Ltd | Construction | 2014 |
| TCG (NI) Ltd | Wholesale & retail | 2014 |
| TD Outside Catering Limited | Hospitality | 2023 |
| Team Frankly Limited | Administrative & support | 2014 |
| Team Mechanical Ltd | Construction | 2010 |
| Teddycare Enterprise Ltd | Manufacturing | 2025 |
| Tela Labs Ltd | Information & communication | 2026 |
| Telford Consultancy Limited | Professional & scientific | 2017 |
| Telford Property Enterprises Limited | Real estate | 2026 |
| Templecarn Limited | Wholesale & retail | 2018 |
| Tenom Limited | Hospitality | 2016 |
| Terra Novaterra Limited | Manufacturing | 2024 |
| Terrawash Limited | Manufacturing | 2025 |
| Tesel Ltd | Information & communication | 2024 |
| TFK Holdings Limited | Financial services | 2025 |
| TFM Portadown Limited | Hospitality | 2019 |
| TGH Property Investment Ltd | Real estate | 2026 |
| TGK Foods Ltd | Hospitality | 2020 |
| TGL Snacks Limited | Hospitality | 2021 |
| THE 1825 Project Limited | Education | 2001 |
| THE 4TH Trimester Ltd | Health & social care | 2022 |
| THE Antrim Down and Armagh Rural Support Network (T.A.D.A.) | Health & social care | 2000 |
| THE ARK Private Day Nursery Ltd | Health & social care | 2010 |
| THE Beeches Professional and Therapeutic Services Limited | Health & social care | 1994 |
| THE Beeches Resource Centre | Education | 1990 |
| THE Bottom Drawer Store (NI) Limited | Wholesale & retail | 2014 |
| THE Boundaries Management Company (Lurgan) Limited | Hospitality | 2012 |