| Square Holdings Limited | Real estate | 2015 |
| Square Real Estate Ltd | Real estate | 2021 |
| SR Autolab Limited | Wholesale & retail | 2026 |
| SR Farm Trading Ltd | Agriculture & fishing | 2020 |
| SRD Holdings N.I Ltd | Financial services | 2022 |
| SRE Farms Limited | Agriculture & fishing | 2025 |
| Srjw Holding Ltd | Financial services | 2024 |
| SRL Global Ltd | Wholesale & retail | 2019 |
| SS Farms Ltd | Agriculture & fishing | 2018 |
| Ssbl Developments Ltd | Construction | 2025 |
| SSS Security Ltd | Construction | 2020 |
| Staffordc UK Ltd | Professional & scientific | 2024 |
| Stand Point to the Sun LP | | 2019 |
| Stanfield Spencer Limited | Other services | 2018 |
| Stanfrey Limited | Wholesale & retail | 2023 |
| Stangmore Farm Ltd | Agriculture & fishing | 2008 |
| Stanwin Lettings Ltd | Real estate | 2021 |
| Star BUS and Taxi Hire Ltd | Transport & logistics | 2022 |
| Stateofthearts Ltd | Other services | 2021 |
| Stayzi Property Management Ltd | Real estate | 2026 |
| Steadystepper Ltd | Transport & logistics | 2024 |
| Steelworx Ltd | Manufacturing | 2014 |
| Steen Commercials Limited | Manufacturing | 2010 |
| Steen Engineering Ltd | Manufacturing | 2019 |
| Steer Safe Accident Management Ltd | Professional & scientific | 2020 |
| Stella Maris Pilgrimages Ltd | Administrative & support | 2025 |
| Stellar Electrical Solutions Ltd | Construction | 2023 |
| Step Training and Learning Limited | Real estate | 2004 |
| Stephen Sheridan Tours Limited | Administrative & support | 2014 |
| Stewart Consulting IRE Ltd | Professional & scientific | 2003 |
| Stewart Engineering (NI) Limited | Manufacturing | 2011 |
| Stewartstown Development Association Limited | Administrative & support | 1992 |
| STM Constructors Limited | Construction | 2020 |
| Stonepark Engineering Limited | Financial services | 2021 |
| Strawberry Lane Management Company Ltd | Households | 2018 |
| Strickland International Limited | Financial services | 2006 |
| Strickland Ireland Limited | Manufacturing | 2011 |
| Strom Wheels Ltd | Wholesale & retail | 2025 |
| Strood Cuisine Ltd | Hospitality | 2015 |
| Strufort Ltd | Manufacturing | 2025 |
| Su's Welcome Ltd | Hospitality | 2020 |
| Summer Garden Foods Ltd | Manufacturing | 2021 |
| Summer Garden Salads Ltd | Wholesale & retail | 2011 |
| Summerisland Consultancy Ltd | Professional & scientific | 2024 |
| Sunlite N.I. Limited | Construction | 2022 |
| Sunny Spot Limited | Other services | 2023 |
| Sunshine Takeaway Limited | Hospitality | 2025 |
| Supreme Foods Ireland Ltd | Manufacturing | 2016 |
| Surepath Coaching & Consulting Ltd | Professional & scientific | 2025 |
| Sweet Spot BDA Ltd | Wholesale & retail | 2024 |
| Sweetez Limited | Wholesale & retail | 2014 |
| Swerve Padel Ltd | Arts & recreation | 2026 |
| Swift Logistics Transport Limited | Transport & logistics | 2011 |
| Swiftflow Ltd | Administrative & support | 2025 |
| Swingsight Ltd | Information & communication | 2026 |
| Sydney Brown & SON Ltd | Construction | 2003 |
| Sydney Mcmullan Limited | Agriculture & fishing | 2014 |
| Syerla Commercial Properties Ltd. | Real estate | 2021 |
| Syerla Developments Ltd | Real estate | 2015 |
| Syerla Enterprises Ltd | Agriculture & fishing | 2012 |
| Syerla Farms Ltd | Agriculture & fishing | 2015 |
| Syerla Finance Limited | Financial services | 2017 |
| Syerla Holdings Ltd | Professional & scientific | 2006 |
| Syerla Homes Ltd | Real estate | 2015 |
| Syerla Properties Limited | Construction | 2013 |
| Sylkie Ireland Ltd | Wholesale & retail | 2020 |
| Synes Services Ltd | Professional & scientific | 2025 |
| Synk Bathrooms Ltd | Construction | 2023 |
| S’More the Merrier Ltd | Wholesale & retail | 2021 |
| T & B Mckenna Ltd | Agriculture & fishing | 2017 |
| T & M Truck Parts Ltd | Wholesale & retail | 2022 |
| T & S Properties (Tyrone) Ltd | Real estate | 2026 |
| T and H Solutions Ltd | Financial services | 2025 |
| T and M Properties Ballytroddan Ltd | Real estate | 2025 |
| T&B Group Holdings Ltd | Financial services | 2018 |
| T.J. Loughlin Contracts Limited | Construction | 2013 |
| T.J. Loughlin Limited | Construction | 1981 |
| T.J.Mckenna and SON Limited | Manufacturing | 1978 |
| Tailored Image Holdings Ltd | Professional & scientific | 2021 |
| Tailored Image Ltd | Wholesale & retail | 1998 |
| TAL 32 Limited | Financial services | 2025 |
| Tamnamore Limited | Hospitality | 2011 |
| Tangent Engineering (IRL) Ltd | Professional & scientific | 2021 |
| TAQ Mechanical Ltd | Construction | 2024 |
| TAQ Property Ltd | Real estate | 2024 |
| Tatathao Ltd | Wholesale & retail | 2024 |
| Taylor Group (Ireland) Ltd | Construction | 2010 |
| Taylormade Credit Limited | Professional & scientific | 2026 |
| TB Media Group Limited | Professional & scientific | 2025 |
| TBC (NI) Limited | Wholesale & retail | 2007 |
| TD Cherry Limited | Extraterritorial | 2022 |
| TD Rigging Ltd | Construction | 2023 |
| Tech 4.0 Ltd | Information & communication | 2020 |
| Tech Group Ltd | Information & communication | 2021 |
| TED Clarke Memorial Trust | Arts & recreation | 2013 |
| Tedco Ltd | Construction | 2020 |
| Teely Farms | Agriculture & fishing | 2018 |
| Teemore Ltd | Wholesale & retail | 2014 |
| Teide Breac Ltd | Information & communication | 2019 |
| Tennyson Murray Ltd | Hospitality | 2026 |