| Smart Auto Clinic Ltd | Wholesale & retail | 2025 |
| Smart Property Holdings Ltd | Real estate | 2016 |
| Smoked Birch Enterprises Limited | Wholesale & retail | 2020 |
| Snax Vending Ltd | Hospitality | 2022 |
| SNC International Ltd | Transport & logistics | 2024 |
| Solacht Ltd | Information & communication | 2026 |
| Solmatix Ltd | Professional & scientific | 2008 |
| Sora Solutions Ltd | Professional & scientific | 2023 |
| SP MAC Services Limited | Construction | 2023 |
| Spring & Airbrake Ireland Limited | Wholesale & retail | 2005 |
| Ssdj Events Ltd | Arts & recreation | 2016 |
| Steepleview Developments Limited | Real estate | 2016 |
| Steepleview Homes Limited | Real estate | 2022 |
| Steepleview Properties Limited | Real estate | 2009 |
| Stephen Addis Consulting Limited | Professional & scientific | 2020 |
| Stewart Home's Ltd | Real estate | 2021 |
| Stewarts Homefront Ltd | Construction | 2025 |
| Stout and About Merch Limited | Manufacturing | 2025 |
| Stratiuum (UK) Ltd | Information & communication | 2023 |
| STS (1988) Ltd | Transport & logistics | 2011 |
| Superior Vape Ltd | Administrative & support | 2017 |
| Survsec Limited | Construction | 2017 |
| Symphony Coatings (Northern Ireland) Limited | Manufacturing | 2025 |
| Sysco Foods NI Limited | Wholesale & retail | 2007 |
| Systemic Solutions FF Ltd | Professional & scientific | 2024 |
| Taekwon-Do (NI) Ltd | Arts & recreation | 2006 |
| Tantastic Group Ltd | Financial services | 2025 |
| Target Express Parcels Limited | | 1998 |
| TAZ Developments Limited | Construction | 2017 |
| Tenfire Limited | Wholesale & retail | 2025 |
| TFS Fire & Security Ltd | Other services | 2023 |
| THE Auction Yard Limited | Wholesale & retail | 2010 |
| THE Belfast Biltong Company Limited | Extraterritorial | 2020 |
| THE Dunlady Arms Limited | Wholesale & retail | 2020 |
| THE Mortgage DOC Limited | Financial services | 2023 |
| THE Poolco Ltd | Water & waste | 2024 |
| THE Present Tree Ltd | Wholesale & retail | 2013 |
| THE Wedding Hub NI Ltd | Information & communication | 2025 |
| THE Well House Cottages Limited | Wholesale & retail | 2022 |
| THE Woof Top Hotel Ltd | Agriculture & fishing | 2025 |
| Theswimco Ltd | Education | 2024 |
| TJ Hood Holdings Ltd | Financial services | 2025 |
| TJ Hood Transport Ltd | Transport & logistics | 1999 |
| TL Solar Limited | Construction | 2022 |
| TLG 93 Ltd | Arts & recreation | 2026 |
| TMC Services Belfast Ltd | Construction | 2022 |
| TMF International (Belfast) Limited | Transport & logistics | 2021 |
| TMF International Transport Limited | Transport & logistics | 2015 |
| Topregal UK Limited | Wholesale & retail | 2021 |
| Total Blinds Limited | Manufacturing | 2016 |
| Total Football Performance Limited | Education | 2026 |
| TPX Handling Ltd | Transport & logistics | 2026 |
| Trained by DT Belfast Ltd | Arts & recreation | 2025 |
| Transport Training Board for Northern Ireland | Real estate | 1991 |
| Transport Training Services (NI) Ltd | Transport & logistics | 2013 |
| Tulisa Ltd | Hospitality | 2021 |
| Tully Consultancy Ltd | Professional & scientific | 2025 |
| Tutoring N.I Ltd | Education | 2023 |
| Ulster Clay Pigeon Shooting Association | Arts & recreation | 1991 |
| Ultra Cleaning Solutions Ltd | Wholesale & retail | 2020 |
| Unique Kitchen & Bedroom Design Ltd | Manufacturing | 2024 |
| Unitech Services Group Limited | Other services | 2004 |
| United Tyre Company Limited | Wholesale & retail | 1978 |
| Valleys Gymnastics Academy Limited | Arts & recreation | 2011 |
| Vehicle Service Centre (N.I.) Limited | Wholesale & retail | 2025 |
| Vets Compared Ltd | Information & communication | 2026 |
| Vupix Ltd | Information & communication | 2025 |
| W J B Moore Building Contractors Limited | Agriculture & fishing | 2008 |
| W M Building & Driveway Specialists Ltd | Administrative & support | 2023 |
| Waterway Industrial Limited | Manufacturing | 2021 |
| Watsons Wind Ltd | Manufacturing | 2025 |
| Whiteside Haulage & Plant Hire Ltd | Transport & logistics | 2026 |
| Wilde Campers Limited | Manufacturing | 2023 |
| WIN Hill Enterprises Ltd | Agriculture & fishing | 2012 |
| WKO Trading Ltd | Wholesale & retail | 2022 |
| Z H Recycling Ltd | Extraterritorial | 2024 |
| Zafco UK Holding Ltd | Wholesale & retail | 2016 |