| Silvius Cars Ltd | Wholesale & retail | 2025 |
| Simon Cook Plumbing & Heating Limited | Construction | 2003 |
| Simon Taylor Funeral Director Ltd | Other services | 2021 |
| Simple Safe Solutions Ltd | Professional & scientific | 2026 |
| Simpsons Fold (New Waltham) Management Limited | Households | 2004 |
| Sims Florists Limited | Wholesale & retail | 2008 |
| Sisaulius Trans Ltd | Transport & logistics | 2023 |
| Siskin Surveys Ltd | Professional & scientific | 2019 |
| Sismatico (U K) Limited | Manufacturing | 1996 |
| Sisters of Steel CIC | Administrative & support | 2025 |
| Site Service Engineering Limited | Administrative & support | 1992 |
| Sivaas Ltd | Wholesale & retail | 2022 |
| SJ Brooks Building Limited | Construction | 2025 |
| SJ Convenience Ltd | Wholesale & retail | 2021 |
| SJC ENT Limited | Health & social care | 2024 |
| SJG Roofing Lincs Limited | Construction | 2009 |
| SJJ Engineering Limited | Professional & scientific | 2015 |
| SJP Signalling Ltd | Professional & scientific | 2022 |
| SJS Agriculture Limited | Wholesale & retail | 1997 |
| SK Gynaecology Limited | Health & social care | 2022 |
| SKA Medical Services Limited | Health & social care | 2020 |
| Skak Property Limited | Real estate | 2020 |
| Skayl Digital Agency Limited | Professional & scientific | 2020 |
| SKB Fishing Tackle Limited | Wholesale & retail | 2012 |
| Skeleton Paintball Ltd | Wholesale & retail | 2022 |
| Skmp Trading Limited | Wholesale & retail | 2025 |
| Skuma Timba Contracts Limited | Construction | 2012 |
| Skuma Timba Limited | Wholesale & retail | 2007 |
| Sky Pirate Ltd | Manufacturing | 2018 |
| Skyflight MCR Ltd | Administrative & support | 2021 |
| Skylark Cottages Limited | Real estate | 2026 |
| Skyline Internet Limited | Information & communication | 2009 |
| Skymark Packaging International Limited | Manufacturing | 1987 |
| SL Distribution Ltd | Transport & logistics | 2016 |
| SL International Consultancy Limited | Wholesale & retail | 2020 |
| Slice & Grill Restaurant Ltd | Hospitality | 2025 |
| Slimzep Limited | Health & social care | 2025 |
| Sljl Holdings Limited | Professional & scientific | 2021 |
| Slot-Warehouse Ltd | Wholesale & retail | 2025 |
| SM Welding Inspection Services Limited | Construction | 2008 |
| Small COG Ltd | Information & communication | 2009 |
| Smart Dens Ltd | Wholesale & retail | 2019 |
| Smart Fulfilment Ltd | Transport & logistics | 2020 |
| Smart Move Lettings and Sales Limited | Real estate | 2012 |
| Smarter Labour Limited | Administrative & support | 2019 |
| Smartmov Ltd | Transport & logistics | 2025 |
| Smash ME Ltd | Hospitality | 2025 |
| Smee Engineering Services Ltd | Manufacturing | 2023 |
| Smith & Slater Developments Ltd | Real estate | 2024 |
| Smith Orthopaedics Limited | Health & social care | 2020 |
| SMITH63 Ltd | Extraterritorial | 2021 |
| Smmsalvage Limited | Wholesale & retail | 2025 |
| Smooth FS Ltd | Financial services | 2019 |
| Smooth Move Removals Ltd | Water & waste | 2018 |
| SMP Brainstorm Ltd | Wholesale & retail | 2025 |
| Smvsh AS Ltd | Hospitality | 2025 |
| SMZ Properties Limited | Real estate | 2017 |
| SN Automotive Limited | Wholesale & retail | 2022 |
| Snack Attack (Scunthorpe) Ltd | Hospitality | 2011 |
| Snack Attack Cafe Ltd | Hospitality | 2024 |
| Snack Attack Express Ltd | Hospitality | 2024 |
| Snake Group Limited | Arts & recreation | 2026 |
| Snap Auto Parts Ltd | Wholesale & retail | 2026 |
| Snap Crackle & Pork Ltd | Hospitality | 2020 |
| Snarewski Properties Ltd | Real estate | 2025 |
| Snelson Engineering Limited | Professional & scientific | 2009 |
| Sneyd's Wonderfeeds Ltd | Wholesale & retail | 2004 |
| SNL Logistics Ltd | Transport & logistics | 2024 |
| SNR Homes Limited | Real estate | 2025 |
| SNR Trans Ltd | Transport & logistics | 2019 |
| Sofia Transport Logistic Ltd | Transport & logistics | 2026 |
| SOK Retail Ltd | Wholesale & retail | 2023 |
| SOK UK Ltd | Wholesale & retail | 2023 |
| Soler Orthopaedics Ltd | Health & social care | 2020 |
| Soluteq Bioplastics Limited | Agriculture & fishing | 2022 |
| Solutions by Jody Limited | Wholesale & retail | 2007 |
| Solutions PLEDGE2LEARN Limited | Education | 2020 |
| Somi Trailers Limited | Manufacturing | 2003 |
| Somprasong Limited | Hospitality | 2017 |
| Sonic Sports Limited | Arts & recreation | 1998 |
| Soran Motors Ltd | Wholesale & retail | 2026 |
| SOS Recovery (Scunthorpe) Limited | Wholesale & retail | 2010 |
| South Bank Carpet and Furniture Ltd | Wholesale & retail | 2026 |
| South Devon General Surgical Services Ltd | Health & social care | 2023 |
| South Yorkshire Truss Solutions Limited | Manufacturing | 2023 |
| Southern Trident Limited | Wholesale & retail | 2017 |
| Southpark Commercials Limited | Wholesale & retail | 2017 |
| Southpark Self Storage Limited | Administrative & support | 2017 |
| Spa Buddy Ltd | Wholesale & retail | 2020 |
| Spa Care UK Ltd | Wholesale & retail | 2020 |
| Spalding Bowl Ltd | Real estate | 2022 |
| Spalding INT Market Ltd | Wholesale & retail | 2018 |
| Spannermonkeylincs Limited | Manufacturing | 2025 |
| Spannermonkeyrecovery Ltd | Manufacturing | 2025 |
| Sparkeit Limited | Manufacturing | 1984 |
| Spav-Inns Transport Limited | Transport & logistics | 2015 |
| Spavin Pallets Limited | Manufacturing | 2004 |
| SPB Group Limited | Administrative & support | 2005 |
| SPC Heating Ltd | Construction | 2014 |
| Special Ceilings Ltd | Construction | 2018 |