| Scott Group Property (EH) Ltd | Real estate | 2025 |
| Scribble and Sketch Ltd | Wholesale & retail | 2025 |
| Scullerymagee Limited | Hospitality | 2021 |
| Sea COW Surf Company Ltd | Wholesale & retail | 2021 |
| Sean Brolly Electrical Ltd | Construction | 2023 |
| Sean Doherty Limited | Information & communication | 2017 |
| Search Workshop Supplies Ltd | Wholesale & retail | 2016 |
| Seasonal Outdoor Services Limited | Administrative & support | 2018 |
| Sedona DL Ltd | Hospitality | 2022 |
| Seeme Limited | Information & communication | 2021 |
| Segt Ltd | Wholesale & retail | 2013 |
| Selco Contractors Limited | Construction | 2000 |
| Select Electrical & Security Services Ltd | Construction | 2013 |
| Select Kidz (Derry) Limited | Hospitality | 2022 |
| Self Store (IRL) Ltd | Transport & logistics | 2018 |
| Selycon Ltd | Information & communication | 2026 |
| Senad Logistics Limited | Health & social care | 2023 |
| Sestina Music | Administrative & support | 2013 |
| SF Motofix Ltd | Wholesale & retail | 2026 |
| Sg-Fibre-Networks Ltd | Construction | 2025 |
| Sgnl Music Group Ltd | Information & communication | 2026 |
| Sgs-Irl Ltd | Professional & scientific | 2025 |
| Shaker&Stone Ltd | Wholesale & retail | 2026 |
| Shan Crochet Designs Ltd | Arts & recreation | 2025 |
| Shane Transport Ltd | Wholesale & retail | 2014 |
| Shannagh Group Ltd | Construction | 2018 |
| Sharon Peaker Flowers Limited | Wholesale & retail | 2005 |
| Shepherds Court Management Company Ltd | Households | 2009 |
| Sheq Management Services Ltd | Administrative & support | 2025 |
| Sheriffs Mountain Stables Ltd | Education | 2025 |
| Sherpa Restaurant Limited | Hospitality | 2025 |
| Shipkey Aparthotel Limited | Hospitality | 2018 |
| Shipquay Investments Limited | Construction | 2002 |
| Shipquay Stores Ltd | Wholesale & retail | 2026 |
| Shirttalesni Limited | Administrative & support | 2025 |
| Shivoo Pictures Ltd | Information & communication | 2021 |
| Shooting Starz Gymnastics Centre of Excellence C.I.C. | Arts & recreation | 2013 |
| Shore Road Developments Limited | Real estate | 2013 |
| Shoreline Utilities Limited | Construction | 2015 |
| Shoreview Holdings Limited | Financial services | 2026 |
| SIA Brow & Beauty Salon Limited | Other services | 2024 |
| Siarn Investments Limited | Real estate | 2019 |
| Siege City Ltd | Arts & recreation | 2025 |
| Simpco Limited | Real estate | 2016 |
| Simply Indian (Derry) Limited | Wholesale & retail | 2015 |
| Sinclair Incorporated Limited | Other services | 2019 |
| Sion Sports and Leisure Ltd | Extraterritorial | 2014 |
| Sipher Therapeutics Ltd | Manufacturing | 2025 |
| Sivakumar Surgical Assisting Limited | Health & social care | 2022 |
| SIX Cinnamon Hall Limited | Real estate | 2024 |
| SIX West Management Co NI Ltd | Households | 2022 |
| Sizing Solutions Limited | Professional & scientific | 2016 |
| Sjir NI Limited | Other services | 2026 |
| SJK Utility Services Ltd | Construction | 2019 |
| SK Facilities Group Ltd | Administrative & support | 2026 |
| SK Trading (N.I.) Ltd | Wholesale & retail | 2017 |
| Skai Automation Ltd | Professional & scientific | 2023 |
| SKD Electrical Limited | Construction | 2023 |
| Skeoge Plant & Haulage Limited | Construction | 2011 |
| Skill School HQ Ltd | Arts & recreation | 2025 |
| Skilled Contracts Ltd | Construction | 2018 |
| Skilled Operations Ltd | Construction | 2023 |
| Skint Hill Ltd | Professional & scientific | 2026 |
| SKYVAC.1 Ltd | Construction | 2018 |
| SL Harkin Contracts UK Limited | Construction | 2022 |
| Slevin Electrical Ltd | Construction | 2025 |
| Slim Jims (Derry) Ltd | Hospitality | 2015 |
| Sloane Projects Ltd | Real estate | 2016 |
| SM Devine Construction Limited | Real estate | 2024 |
| SM Devine Land and Property NI Ltd | Real estate | 2015 |
| SM Devine Ltd | Construction | 2018 |
| SM Legend Media Ltd | Professional & scientific | 2014 |
| SM Marketing Solutions Limited | Wholesale & retail | 2022 |
| SM Security (Ireland) Ltd | Administrative & support | 2019 |
| SMA Foods Limited | Hospitality | 2026 |
| Small Dog Productions Ltd | Professional & scientific | 2018 |
| Smart Save Utilities Ltd | Professional & scientific | 2016 |
| Smartreach Solutions Ltd | Information & communication | 2025 |
| Smartwall Install Limited | Construction | 2022 |
| Smartwall Limited | Construction | 2021 |
| SMC Civils Ltd | Construction | 2021 |
| SMD Real Estate Ltd | Real estate | 2025 |
| Smdb Healthcare Ltd | Wholesale & retail | 2024 |
| SMG Project Management Ltd | Administrative & support | 2016 |
| Smithdehn NI Ltd | Administrative & support | 2014 |
| SMK and Co Accounting Limited | Professional & scientific | 2025 |
| SML Contracts (Derry) Limited | Construction | 2016 |
| SMM Drylining Ltd | Construction | 2018 |
| SMR Diagnostics Limited | Health & social care | 2024 |
| Smrt Gallagher Ltd | Health & social care | 2025 |
| SMS Power Ltd | Construction | 2025 |
| SO Good Juice Ltd | Wholesale & retail | 2019 |
| Soal Creative Limited | Professional & scientific | 2023 |
| SOC Construction Limited | Construction | 2022 |
| Sodashui Ltd | Wholesale & retail | 2025 |
| Sohan S Kular Ltd | Hospitality | 2010 |
| Soitis Properties Limited | Real estate | 2022 |
| Solara Wellness Hub Ltd | Health & social care | 2025 |
| Solas Living Limited | Construction | 2025 |
| Somar Contracts Limited | Construction | 2017 |