| Snowbird Christmas Trees Ltd | Agriculture & fishing | 2022 |
| Society of Model Aeronautical Engineers Limited(The) | Arts & recreation | 1948 |
| Soil Conservation Limited | Agriculture & fishing | 2022 |
| Sojlinfin Ltd | Wholesale & retail | 2021 |
| Sokanya Foods Limited | Wholesale & retail | 2026 |
| Solar Forever Ltd | Construction | 2024 |
| Solo Atelier Interior Design Ltd | Professional & scientific | 2023 |
| Soloamore Ltd | Hospitality | 2020 |
| Sonia Perkins Ltd | Wholesale & retail | 2011 |
| Soodgra Ltd | Wholesale & retail | 2021 |
| Sooteh Delan Ltd | Hospitality | 2016 |
| Sophie Burkett Limited | Professional & scientific | 2007 |
| Soulace Limited | Manufacturing | 2012 |
| Soulor Consulting Ltd | Professional & scientific | 2012 |
| South Holland Property Rentals Limited | Real estate | 2021 |
| South Witham Interiors Ltd | Construction | 2015 |
| South Witham Landscapes Ltd | Administrative & support | 2023 |
| Sovereign Energy Ltd | Construction | 2024 |
| Spartan Detailing Limited | Administrative & support | 2024 |
| Specialised Auto Maintenance Ltd | Wholesale & retail | 2011 |
| Specialised Chemicals Limited | Wholesale & retail | 1973 |
| Spectrum Physiotherapy Ltd | Health & social care | 2011 |
| Spectrum Wellness and Performance Ltd | Health & social care | 2017 |
| Speediweld Autos Limited | Wholesale & retail | 2005 |
| Spellbindingsky Ltd | Administrative & support | 2020 |
| Spidim Ltd | Construction | 2024 |
| Spitalgate Developments Limited | Other services | 2009 |
| Splf Ltd | Wholesale & retail | 2021 |
| Spore & Anvil Ltd | Agriculture & fishing | 2025 |
| Sportex AL -Sports Surfaces Ltd | Construction | 2018 |
| Sportex AL Holdings Ltd | Real estate | 2023 |
| Sportex AL Limited Partnership | | 2013 |
| Spring Green Homes Ltd | Real estate | 2024 |
| Spring Lane Services Limited | Wholesale & retail | 2003 |
| Springfield Maintenance Services Ltd | Construction | 2017 |
| Sprinters Edge Ltd | Arts & recreation | 2023 |
| Sqlutions Limited | Information & communication | 2007 |
| Square Root Accounting Ltd | Professional & scientific | 2026 |
| Squeaky Clean by Alex's Team Ltd | Administrative & support | 2024 |
| SRG Elite Sportswear Ltd | Wholesale & retail | 2019 |
| SRI Venkateshwara Enterprises Ltd | Wholesale & retail | 2022 |
| SSB Complete Ltd | Hospitality | 2023 |
| SSD Hotels Limited | Hospitality | 2025 |
| Ssema & Co. Limited | Wholesale & retail | 2026 |
| SSH Healthcare Ltd | Health & social care | 2013 |
| SSW Leadership Limited | Professional & scientific | 2021 |
| ST Vehicles Ltd | Wholesale & retail | 2026 |
| Stable View Management Limited | Households | 2025 |
| Stadia Group Limited | Wholesale & retail | 2009 |
| Stage and Prosper Ltd | Hospitality | 2021 |
| Stainby Stone Ltd. | Mining & quarrying | 2016 |
| Stake Your Claim Limited | Financial services | 2011 |
| Stamford Property Company Limited | Construction | 1995 |
| Stamford Shepherd Huts Ltd | Manufacturing | 2020 |
| Steamtorch Ltd | Administrative & support | 2020 |
| Stef 79 Limited | Construction | 2018 |
| Step Ahead Productions Ltd | Arts & recreation | 2019 |
| Sterling & Stone Properties Ltd | Real estate | 2025 |
| Stetersmo Ltd | Administrative & support | 2021 |
| Steve Squirrel Ltd | Other services | 2025 |
| Steve Turner Design Limited | Professional & scientific | 2000 |
| Stewart RE Limited | Financial services | 1999 |
| Stewart Thorpe (Agricultural Services) Limited | Wholesale & retail | 1979 |
| Stirz Limited | Hospitality | 2020 |
| Stitch & Co UK Limited | Wholesale & retail | 2024 |
| Stoatally Different Ltd | Professional & scientific | 2023 |
| Stoical LLP | | 2006 |
| Stoke Rochford Catering Ltd | Hospitality | 2026 |
| Stoke Rochford Golf Club (1924) Ltd | Arts & recreation | 2021 |
| Stoke Rochford Golf Club Ltd | Arts & recreation | 2017 |
| Stommpy UK Limited | Manufacturing | 2014 |
| Stone (2018) Company | Financial services | 2019 |
| Stone Day Limited | Real estate | 2021 |
| Stone Designs & Construction Ltd | Construction | 2020 |
| Stonebow Financial Services Limited | Financial services | 2014 |
| Stonebow Financial Solutions Ltd | Financial services | 2025 |
| Stoneleigh Financial Services LLP | | 2004 |
| Stoneway Developments Limited | Construction | 1999 |
| Stop & Play Limited | Information & communication | 2024 |
| Strawlock LLP | | 2023 |
| Strays of Market Harborough Ltd | Hospitality | 2020 |
| Strays of Newark Limited | Hospitality | 2020 |
| Strays of Oakham Limited | Hospitality | 2020 |
| Strays of Stamford Limited | Hospitality | 2019 |
| Streamline Badger LLP | | 2014 |
| Street by IPE Ltd | Wholesale & retail | 2023 |
| Street Houses Limited | Real estate | 2003 |
| Strensham LLP | | 2006 |
| Stroud Partners LLP | | 2007 |
| Studdridge Limited | Financial services | 2017 |
| Studio Lumo Limited | Extraterritorial | 2015 |
| Stump Cross Associates Limited | Professional & scientific | 1999 |
| Sturgii LLP | | 2009 |
| Stweissntu Limited | Professional & scientific | 2025 |
| Sudbrook Park Limited | Other services | 2021 |
| Sudwelle Properties Limited | Real estate | 2017 |
| Suited Solutions Limited | Construction | 2012 |
| Summit Norway Limited | Financial services | 2011 |
| Sun YU Ltd | Hospitality | 2015 |
| Sunnybank Limited | Hospitality | 2003 |