| Rntl Ltd | Real estate | 2021 |
| Robb Trading Ltd | Wholesale & retail | 2015 |
| Robinson Property Group Ltd | Real estate | 2017 |
| Rock of Fire Centre Ltd | Health & social care | 2019 |
| Rock Wonder Design Limited | Manufacturing | 2023 |
| Rockcote NI Ltd | Construction | 2024 |
| Rocksure Fire & Security Ltd | Wholesale & retail | 2024 |
| Rocky Place Investments Ltd | Financial services | 2025 |
| Rogar Haulage Ltd. | Transport & logistics | 2018 |
| Roodney Limited | Wholesale & retail | 2025 |
| Roofclad Profiles Limited | Manufacturing | 2007 |
| Rookbay Management LLP | | 2013 |
| Rose Carant Ltd | Real estate | 2015 |
| Rosses Enterprises Limited | Real estate | 2017 |
| Routineroo Ltd | Information & communication | 2024 |
| ROY Hanna Motors Limited | Wholesale & retail | 2018 |
| Runto Trading Limited | Wholesale & retail | 2024 |
| S and L Property Ltd | Real estate | 2018 |
| S C Rentals (Antrim) Ltd | Administrative & support | 2019 |
| S Trade International Ltd | Wholesale & retail | 2021 |
| S&E Caretrade Ltd | Wholesale & retail | 2012 |
| S.L. FRY Limited | Construction | 2015 |
| S.W. Gordon & Co Limited | Real estate | 1963 |
| Sacha Henry Limited | Construction | 2025 |
| Sakura NI Property Ltd | Real estate | 2024 |
| SAM Residential Homes Limited | Construction | 2016 |
| Satcare Health Limited | Administrative & support | 2022 |
| Sativaate Ltd | Health & social care | 2023 |
| Savage Collectables Ltd | Wholesale & retail | 2024 |
| Schrader Electronics Limited | Manufacturing | 1991 |
| Scratch Golf Performance Ltd | Arts & recreation | 2026 |
| Sdij Group Ltd | Real estate | 2025 |
| Seamless Laundry Ltd | Administrative & support | 2024 |
| Seanita Limited | Construction | 2022 |
| Seaview 87 Management Company Limited | Households | 2023 |
| Sentry Plant Hire Ltd | Hospitality | 1999 |
| Seqas ( Specialised External Quality Assessment Service) Ltd | Information & communication | 2025 |
| Sequoia for Business Limited | Professional & scientific | 2024 |
| Serene Meadow Limited | Health & social care | 2024 |
| Sfblueprint Ltd | Professional & scientific | 2024 |
| Sfoods Limited | Hospitality | 2025 |
| Sgrc NO. 1 Limited | Information & communication | 2018 |
| Shades Contracts Ltd | Construction | 2006 |
| Shadow Films Limited | Information & communication | 2020 |
| Shanes Castle Estates Company Limited | Agriculture & fishing | 1982 |
| Shankbridge Limited | Real estate | 2022 |
| Shannon Site Solutions Ltd | Construction | 2013 |
| Shauneen Horner Ltd | Health & social care | 2025 |
| Shawkins Associates Ltd | Other services | 2024 |
| Shopilix Limited | Wholesale & retail | 2025 |
| Shortheath Holdings Ltd | Financial services | 2024 |
| Shuz 4 U Antrim Limited | Wholesale & retail | 2021 |
| Sidera Ltd | Health & social care | 2025 |
| Silverpine Housing Ltd | Real estate | 2025 |
| Simba Developments NO.1 Limited | Construction | 2021 |
| Simba Developments NO.2 Limited | Construction | 2024 |
| Simpsons Newsagents Limited | Wholesale & retail | 2026 |
| Sinclair Estates and Property (NI) Ltd | Real estate | 2023 |
| Sinrg Limited | Construction | 2025 |
| Sisk Response Services Limited | Construction | 2019 |
| SIX Mile Autos & SM Hire Ltd | Wholesale & retail | 2025 |
| SIX Mile Water Trust | Other services | 2013 |
| Sixmile Accountancy Ltd | Professional & scientific | 2025 |
| SJA Groundworks Limited | Construction | 2019 |
| SJP Housing Limited | Real estate | 2022 |
| Skelpielimmer Ltd | Arts & recreation | 2024 |
| Skinakin Ltd | Professional & scientific | 2018 |
| Skycrew Ltd | Transport & logistics | 2024 |
| Skye (UK) Limited | Wholesale & retail | 2013 |
| Skyhook Antrim | Extraterritorial | 2013 |
| Slaughdon Ltd | Wholesale & retail | 2013 |
| Small & Marken Solicitors Limited | Professional & scientific | 2011 |
| Sola Studios Antrim Ltd | Arts & recreation | 2026 |
| Solsted Ltd | Professional & scientific | 2019 |
| SOM Properties NO.3 (NI) Ltd | Real estate | 2019 |
| Soulo Games Ltd | Information & communication | 2025 |
| Source Development International Limited | | 2001 |
| SP Group Global Ltd | Construction | 2016 |
| Spantherm Limited | Construction | 2011 |
| Sperrin Manufacturing Limited | Real estate | 2015 |
| Spins N Wins Ltd | Wholesale & retail | 2022 |
| Splash Academy N.I. Limited | Education | 2025 |
| Split Level Developments Limited | Real estate | 2016 |
| Sporting Links Limited | Arts & recreation | 2024 |
| Sports Cards NI Ltd | Wholesale & retail | 2026 |
| Spray Craft Limited | Construction | 2024 |
| Springfarm Architectural Mouldings Group Ltd | Financial services | 2024 |
| Springfarm Architectural Mouldings Limited | Manufacturing | 1990 |
| Springvale Farmland LLP | | 2025 |
| Springwell Contracts Ltd | Construction | 2020 |
| Srcl Limited | | 2008 |
| Stack IT High NI Limited | Wholesale & retail | 2024 |
| Stagforge Ltd | Manufacturing | 2023 |
| Star Cargo Balikbayan Services Ltd | Transport & logistics | 2026 |
| Steven Fisher Resin Ltd | Construction | 2023 |
| Stewart Commercials Ltd | Administrative & support | 2013 |
| Stewart Property Investments Ltd | Real estate | 2018 |
| Sthigh Start Limited | Wholesale & retail | 2025 |
| Stitch and Weave Limited | Hospitality | 2023 |
| STJ Enterprises Ltd | Wholesale & retail | 2025 |