| SMA2 Property Investment Ltd | Real estate | 2026 |
| Smart Associates (Productions) Limited | Information & communication | 2014 |
| Smart Developments (Cornwall) Limited | Construction | 2017 |
| Smart Finish Paint & Body Repairs Limited | Other services | 2025 |
| Smart Home Security Limited | Administrative & support | 2016 |
| Smart Interactive Ltd | Information & communication | 2004 |
| Smart People UK Limited | Administrative & support | 2006 |
| Smart Project Professionals Ltd | Information & communication | 2019 |
| Smart Repair North East Limited | Wholesale & retail | 2018 |
| Smart Repairs Lincolnshire Limited | Wholesale & retail | 2026 |
| Smarter Comparison Ltd | Information & communication | 2005 |
| Smartflow Couplings Ltd | Manufacturing | 2015 |
| Smarvin Limited | Health & social care | 2019 |
| Smethurst & Co LLP | | 2016 |
| Smethurst Accountancy Services Ltd | Professional & scientific | 2025 |
| Smile 4 YOU Online Limited | Wholesale & retail | 2026 |
| Smile Craft Family Care Limited | Health & social care | 2026 |
| Smile Land Limited | Health & social care | 2022 |
| SMITHPROPCO5 Ltd | Construction | 2025 |
| SMJ Pubs Limited | Hospitality | 2018 |
| Smoke EYE Publishing Ltd | Information & communication | 2012 |
| SMR Electrical Solutions Limited | Construction | 2024 |
| SMS Access Limited | Construction | 2018 |
| Smsh Investments Ltd | Real estate | 2026 |
| SMT (Lincs.) Enterprises Ltd. | Other services | 2018 |
| SMZ Medicals Ltd | Health & social care | 2014 |
| Snape Homes Limited | Construction | 2001 |
| Snax - Corner ( Lincs.) Ltd | Hospitality | 2025 |
| Sneaky Duck Catering Limited | Hospitality | 2018 |
| Snell Civil Engineering Limited | Construction | 2016 |
| Snell Electrical Services Limited | Construction | 2015 |
| SNJ Marketing Ltd | Professional & scientific | 2019 |
| Snodon Lodges Ltd | Hospitality | 2026 |
| Snugfit (Grimsby) Limited | Construction | 2024 |
| Soal Property Limited | Real estate | 2021 |
| Soap and Honey Limited | Professional & scientific | 2016 |
| Social Media Support Limited | Administrative & support | 2015 |
| SOF2024 Ltd | Transport & logistics | 2024 |
| Sofia Logistics Ltd | Transport & logistics | 2021 |
| Sojo Stay Group Ltd | Real estate | 2018 |
| Sojourn Ltd | Construction | 2015 |
| Solarsave Ltd | Construction | 2022 |
| Sole Foot Care Ltd | Other services | 2016 |
| Sole Sisters LDN Limited | Wholesale & retail | 2025 |
| Solid Entertainments Tickets Limited | Wholesale & retail | 2008 |
| Solihull Renovations Ltd | Administrative & support | 2016 |
| Solplus Energy Solutions Limited | Construction | 2015 |
| Solve Legal Limited | Professional & scientific | 2014 |
| Solvia Property Ltd | Real estate | 2026 |
| Somerby Vineyards Limited | Manufacturing | 2006 |
| Somerscales (Timber Merchants) Limited | Transport & logistics | 1983 |
| Somerscales Heavy Haulage Limited | Transport & logistics | 2009 |
| Somerscales Ltd | Extraterritorial | 2016 |
| Sonas Engineering Limited | Professional & scientific | 2025 |
| Sonic Light Ltd | Wholesale & retail | 2022 |
| Sooa & Associates Ltd | Other services | 2024 |
| Sophie Iona Limited | Arts & recreation | 2019 |
| SOR Transport Ltd | Transport & logistics | 2026 |
| Sorority Sisters Beauty Limited | Other services | 2022 |
| SOS Recruitment Solutions (London) Limited | Administrative & support | 2015 |
| Soufi Consortium Private Limited | Administrative & support | 2017 |
| Soundloc Ltd | Wholesale & retail | 2017 |
| Source Four Limited | Information & communication | 2003 |
| South Bank Alarms Ltd | Administrative & support | 1999 |
| South Bank Finance Ltd. | Real estate | 2002 |
| South Bank Marine (Charts) Limited | Other services | 1996 |
| South Bay Properties Limited | Households | 2003 |
| South Brand Builders Limited | Professional & scientific | 2001 |
| South Coast Chauffeurs Ltd | Transport & logistics | 2015 |
| South Coast Staffing Ltd | Health & social care | 2018 |
| South Humberside Suspended Ceilings Limited | Construction | 1977 |
| South Sea Lane Cottages Limited | Real estate | 2004 |
| South Stock Limited | Agriculture & fishing | 2013 |
| South West Glazing Services Ltd | Extraterritorial | 2011 |
| Southam Services (Lincs) Limited | Construction | 2017 |
| Southbank Asset Management Limited | Administrative & support | 2007 |
| Southcoates Lane Ltd | Real estate | 2019 |
| Sovereign Tiling Limited | Construction | 2019 |
| Sowmya Consultancy Ltd | Real estate | 2019 |
| SP Contract Services Ltd | Professional & scientific | 2018 |
| Space Between US Ltd | Health & social care | 2025 |
| Spaight FLY Fishing Limited | Wholesale & retail | 2023 |
| Spalding Apparel Limited | Wholesale & retail | 2009 |
| Sparge Technical Limited | Professional & scientific | 2020 |
| Sparkeys Property Ltd | Real estate | 2017 |
| Sparrow Golf Academy Limited | Education | 2010 |
| Spartan Property Developers Limited | Construction | 2015 |
| SPC International (Food) Limited | Wholesale & retail | 2000 |
| SPD Aerospace Ltd | Manufacturing | 2019 |
| Specialist Property Services Limited | Construction | 2017 |
| Specialist Vocational Training Limited | Education | 2008 |
| Spectre Safety Consultants Ltd | Professional & scientific | 2025 |
| Spectrum Chimney Sweeps & Services Ltd | Administrative & support | 2021 |
| Spectrum Fostering Agency Limited | Health & social care | 2012 |
| Spectrum Group Services Limited | Health & social care | 2018 |
| Spectrum Print Limited | Manufacturing | 2024 |
| Spektrum 24 Limited | Administrative & support | 2018 |
| SPH Property Services (GY) Limited | Construction | 2012 |
| Spinedent Limited | Health & social care | 2013 |
| Spinner Surf Ltd | Arts & recreation | 2021 |