| SON & Moon Ltd | Hospitality | 2019 |
| SON Joinery Limited | Construction | 2015 |
| Sona Space Ltd | Hospitality | 2025 |
| Soulbound Security Ltd | Information & communication | 2025 |
| Source Financial Limited | Information & communication | 2012 |
| Source Maintenance Solutions Limited | Construction | 2026 |
| South William Street Projects Ltd | Real estate | 2022 |
| Southhall Travel & Services Ltd | Wholesale & retail | 2025 |
| Space Hub Ltd | Water & waste | 2019 |
| Sparkling Maids Limited | Administrative & support | 2003 |
| SPC Consulting (NI) Limited | Professional & scientific | 2013 |
| SPD (Derry) Ltd | Hospitality | 2013 |
| Spencer Catering Co. Ltd | Hospitality | 2019 |
| Spencer Road Developments Limited | Real estate | 2013 |
| Spencer Road Parking & Storage Ltd | Real estate | 2025 |
| Sperrinfinn Ltd | Hospitality | 2026 |
| SPN Property Ltd | Real estate | 2015 |
| Sport Tees Holdings Limited | Wholesale & retail | 2025 |
| Sportbnk Ltd | Information & communication | 2025 |
| SPR Assets Ltd | Real estate | 2022 |
| Spratt Vehicle Solutions Ltd | Wholesale & retail | 2024 |
| Springhill Meadows Limited | Real estate | 2016 |
| Springtown Cash & Carry Limited | Wholesale & retail | 1992 |
| Springtown Kitchens Limited | Manufacturing | 2013 |
| Sproules Jewellers Limited | Wholesale & retail | 2014 |
| SR Skye Limited | Arts & recreation | 2012 |
| Sripada Dent Ltd | Health & social care | 2023 |
| ST Columb's School of Music Ltd | Education | 2019 |
| ST Pauls Books and Gifts Ltd | Wholesale & retail | 2026 |
| ST Raphael Property Ltd | Real estate | 2018 |
| ST Services London Ltd | Information & communication | 2026 |
| ST. Canice's Educational Trust | Professional & scientific | 1987 |
| ST. Columb's Diocesan Trust | Professional & scientific | 1977 |
| ST. Columbs Park Reconciliation Trust | Administrative & support | 1993 |
| STA Audio Visual Limited | Professional & scientific | 2015 |
| Stake Tech Limited | Information & communication | 2025 |
| Star 3 Group Ltd | Wholesale & retail | 2017 |
| Star Arcade Limited | Extraterritorial | 2021 |
| Star Commercial Properties Limited | Construction | 2021 |
| Star Connections Dating Ltd | Other services | 2024 |
| Star Value Limited | Wholesale & retail | 1997 |
| Statik Home Ltd | Information & communication | 2005 |
| Station 8 Social Media Limited | Professional & scientific | 2024 |
| Station Accommodations Limited | Hospitality | 2018 |
| Steam & Generation Services (NI) Ltd | Manufacturing | 2011 |
| Steve Reid Roofing Ltd | Construction | 2011 |
| Stewart & Mcconnell Building Contractors (Derry) Limited | Construction | 1979 |
| STN Derry Ltd | Hospitality | 2023 |
| Stonebrook Developments Limited | Construction | 2012 |
| Stoneybrook Management Company Ltd | Extraterritorial | 2014 |
| Stookeen Limited | Real estate | 2018 |
| STORAGE4YOU Limited | Real estate | 2019 |
| Store & Go Limited | Transport & logistics | 2019 |
| Storm Enterprises Ltd | Hospitality | 2021 |
| Stormlick Ltd | Health & social care | 2018 |
| Strabane Road Developments Limited | Construction | 2018 |
| Strae Group Ltd | Financial services | 2021 |
| Straeview Limited | Construction | 2013 |
| Strategic Support (NI) Ltd | Professional & scientific | 2023 |
| Strathmore Medical & Legal Services Ltd. | Health & social care | 2013 |
| Stratum Management Ltd | Professional & scientific | 2021 |
| Structure Tech Design Ltd | Professional & scientific | 2019 |
| Student Services Centre Ltd | Professional & scientific | 2024 |
| Studio 2 Creative Enterprises C.I.C. | Arts & recreation | 2016 |
| Studio Red I Limited | Professional & scientific | 2001 |
| STUDIO53 Enterprises Ltd | Hospitality | 2022 |
| Stunt City Ltd | Arts & recreation | 2023 |
| Stute Youth & Community Hub | Arts & recreation | 2024 |
| SUB Fresh Restaurants Ltd | Hospitality | 2009 |
| Sudbury Avant Garde Developments Limited | Construction | 2024 |
| Sudbury Developments Limited | Construction | 2019 |
| Summerland Store Limited | Wholesale & retail | 2026 |
| Sunny Days Ltd | Information & communication | 2019 |
| Sunny Days Media Ltd | Information & communication | 2023 |
| Super Limited | Wholesale & retail | 2024 |
| Superior Two Ltd | Wholesale & retail | 2018 |
| SUPPLEMENTS101 Ltd | Wholesale & retail | 2025 |
| Supplybuy Limited | Extraterritorial | 2012 |
| Sure GAS Utilities Ltd | Construction | 2015 |
| Suredrains Ltd | Construction | 2025 |
| Surefill Insulation Limited | Manufacturing | 2012 |
| Surepath Surveying Ltd | Construction | 2025 |
| Swan Salon Ltd | Other services | 2017 |
| Swan Spa Culmore Ltd | Other services | 2017 |
| SWF Holdings (Derry) Ltd | Financial services | 2019 |
| Swift Shift Services Ltd | Information & communication | 2023 |
| Swilly Abbey Ltd | Professional & scientific | 2025 |
| Swilly Sky Ltd | Administrative & support | 2026 |
| Switch Business Systems (NI) Limited | Information & communication | 2014 |
| Swyft-Hr Ltd | Administrative & support | 2025 |
| Syenna Eglinton Limited | Other services | 2017 |
| Synckit Limited | Information & communication | 2022 |
| Synergy Personal Training Ltd | Arts & recreation | 2019 |
| T Linton Contracts Ltd | Construction | 2026 |
| T MAC Joinery Ltd | Construction | 2022 |
| T O'Connell (Utilities) Limited | Construction | 2011 |
| T Street Cafe Limited | Hospitality | 2019 |
| T&C Property Management Company Limited | Households | 2021 |
| T&E Howie Limited | Professional & scientific | 2013 |
| T&V Medical Limited | Health & social care | 2017 |