| Smart Livin Limited | Extraterritorial | 2022 |
| Smart Shelves Company Limited | Wholesale & retail | 2016 |
| Smart Tomas Limited | Wholesale & retail | 2018 |
| Smartbox Self Storage Limited | Transport & logistics | 2004 |
| Smarte Carte UK Limited | Administrative & support | 2006 |
| Smartscan Limited | Manufacturing | 1989 |
| SMB Tranport Ltd | Transport & logistics | 2025 |
| Smhn Investments Limited | Real estate | 2025 |
| Smith and Sniff Industries Limited | Information & communication | 2023 |
| Smjs Property Ltd | Construction | 2023 |
| SML Europe Limited | Manufacturing | 1998 |
| Smoke & Braai Ltd | Hospitality | 2019 |
| Smores Properties Limited | Real estate | 2022 |
| Snak N Kans Ltd | Wholesale & retail | 2025 |
| Snapsalehouse Limited | Wholesale & retail | 2025 |
| SNL Holdings Ltd | Real estate | 2025 |
| Snooze Rooms Ltd | Hospitality | 2015 |
| Snowbridge Homes Limited | Construction | 2018 |
| Snuggly Ducklings Day Nursery Ltd | Health & social care | 2026 |
| So&Co Transport Ltd | Transport & logistics | 2025 |
| Sobefy Ltd | Wholesale & retail | 2020 |
| Socl Ltd | Professional & scientific | 2025 |
| Softgeter Ltd | Wholesale & retail | 2025 |
| SOFY22TRANS Ltd | Transport & logistics | 2025 |
| Solace Care Bureau Ltd | Health & social care | 2023 |
| Solar Union Limited | Manufacturing | 2010 |
| SOLAR4SHAW Ltd | Construction | 2020 |
| Solarizing Limited | Construction | 2014 |
| Solmaztek Ltd | Other services | 2022 |
| Soloris Ltd | Construction | 2024 |
| Soltan Sell Ltd | Information & communication | 2025 |
| Solution Care 247 Ltd | Public administration | 2017 |
| Solve Recruit UK Limited | Administrative & support | 2024 |
| Sonmill Ltd | Professional & scientific | 2024 |
| Sonowave Limited | Professional & scientific | 2017 |
| Sonya & Meryem Fast Food Ltd | Hospitality | 2018 |
| Sophenna Holdings Limited | Financial services | 2025 |
| Sorin Gosman Ltd | Wholesale & retail | 2017 |
| SOS Property Management Services Limited | Real estate | 2019 |
| Soteria Workwear Limited | Wholesale & retail | 2021 |
| Sotizzy Business Services Ltd | Information & communication | 2025 |
| Southern Group Laboratory Limited | Manufacturing | 1992 |
| Southern Halt Limited | Hospitality | 2022 |
| Southern Skies Health and Wellness Limited | Health & social care | 2020 |
| Sovereign Construction Group Limited | Construction | 2017 |
| SP Drivers Ltd | Other services | 2019 |
| SP Home Care Ltd | Health & social care | 2022 |
| SP Investments Ltd | Professional & scientific | 2016 |
| SP Nadolski Limited | Transport & logistics | 2017 |
| SP Sales Consultancy Limited | Professional & scientific | 2023 |
| Spaces 4 U Limited | Real estate | 2021 |
| Spaces Residential Ltd | Real estate | 2025 |
| Spark Guard Fire Safety Services Limited | Manufacturing | 2025 |
| Sparkle Pro Maintenance Ltd | Real estate | 2026 |
| Sparkle-Pro Cleaning Services Ltd | Administrative & support | 2025 |
| Sparklyn Ltd | Administrative & support | 2025 |
| Sparta Transport Ltd | Transport & logistics | 2024 |
| Spearhead Logistics Ltd | Transport & logistics | 2026 |
| Specialised Projects Limited | Manufacturing | 2005 |
| Spectrans One Ltd | Transport & logistics | 2025 |
| Speechless Global Ventures Limited | Transport & logistics | 2022 |
| Speedshift Solutions Ltd | Transport & logistics | 2024 |
| Spice Lemon Limited | Hospitality | 2025 |
| Spice Village Corby Limited | Hospitality | 2025 |
| Spike Design & Marketing Limited | Professional & scientific | 2002 |
| Spinney Close (Warmington) Management Company Limited | Households | 2021 |
| Spirol Industries Limited | Manufacturing | 1960 |
| Spitfire Energy Hold Co Limited | Administrative & support | 2025 |
| Spitfire Energy Limited | Administrative & support | 2024 |
| SPL Properties Ltd | Real estate | 2025 |
| Sports DUE Diligence Limited | Administrative & support | 2026 |
| Spot on Consulting Ltd | Professional & scientific | 2023 |
| Spot-On Healthcare Limited | Health & social care | 2017 |
| SPR Spray Paint Refurbishment Limited | Construction | 2022 |
| Spraylat International Limited | Manufacturing | 1992 |
| Square & Compass Auctioneers Ltd | Wholesale & retail | 2025 |
| Square Hippo Limited | Extraterritorial | 2020 |
| Squeeze Nature Limited | Manufacturing | 2025 |
| Squires Court (Kettering) Management Company Limited | Households | 1989 |
| Squirrels Day Nursery (Corby) Limited | Education | 2004 |
| Sr-Fr Services Ltd | Wholesale & retail | 2023 |
| SRB93 Logistics Ltd | Wholesale & retail | 2022 |
| SRG Park Holdings Limited | Real estate | 2009 |
| SRG Parks Limited | Real estate | 2015 |
| SRG Smart Repairs Ltd | Wholesale & retail | 2025 |
| SRM Lettings Limited | Real estate | 2016 |
| SRM Payroll Limited | Professional & scientific | 2017 |
| Sslproxy Limited | Transport & logistics | 2026 |
| Sstn Services Limited | Administrative & support | 2024 |
| ST Automotive (Raunds) Limited | Wholesale & retail | 2026 |
| ST Dunstan's Opco Limited | Real estate | 2014 |
| ST Logistics Ltd | Transport & logistics | 2022 |
| ST. James Snooker Club Limited | Arts & recreation | 2015 |
| ST. Whites Stone Limited | Manufacturing | 2003 |
| Staci the Breastfeeding Midwife Ltd | Information & communication | 2023 |
| Staff Recruitment UK Limited | Administrative & support | 2024 |
| Staffhive Ltd | Administrative & support | 2024 |
| Stafford Moor Limited | Hospitality | 2014 |
| Stamford Home FIX Ltd | Other services | 2020 |
| Stampenation Enterprises Limited | Administrative & support | 2025 |