| SJW Mill Consulting Limited | Professional & scientific | 2017 |
| SK Civils Limited | Construction | 2016 |
| SK Clothing Ltd | Wholesale & retail | 2025 |
| SK Electrical (Lincoln) Limited | Construction | 2025 |
| SK Homes Property Limited | Real estate | 2025 |
| SK8S (UK) Limited | Arts & recreation | 2011 |
| SKA & K (B) Ltd | Extraterritorial | 2026 |
| Skald Ltd | Arts & recreation | 2022 |
| Skaymanphillipsonpub Ltd | Hospitality | 2024 |
| SKB Social Care Ltd | Health & social care | 2021 |
| SKC Property Management Services Ltd | Households | 2025 |
| Skeggøx Ltd | Manufacturing | 2022 |
| Skegness and Charles Pubs Limited | Hospitality | 2026 |
| Skegness and Yorkshire Pubs Ltd | Hospitality | 2018 |
| Skegness Cricket Lawn Tennis & Sports Company Limited(The) | Real estate | 1921 |
| Skegness Hospitality Ltd | Hospitality | 2026 |
| Skelly Pizza Ltd | Hospitality | 2025 |
| Skidmore Building Contractors Ltd | Construction | 2020 |
| SKILLS4LIFE Ltd. | Education | 2014 |
| Skillsreach Limited | Professional & scientific | 2011 |
| Skin Rewind Limited | Health & social care | 2018 |
| Skincare Residence Limited | Health & social care | 2025 |
| Skircoat Project Management Limited | Professional & scientific | 2018 |
| Skwr Management Services Ltd | Professional & scientific | 2023 |
| Skybay Limited | Real estate | 2024 |
| Skybook Limited | Professional & scientific | 2004 |
| Skylark Build Ltd | Construction | 2018 |
| Skylark Construct Ltd | Construction | 2018 |
| Skylark Fostering Limited | Health & social care | 2023 |
| Skylark Holdings Ltd | Financial services | 2018 |
| Skylark Homes Ltd | Construction | 2011 |
| Skylark Living Ltd | Real estate | 2026 |
| Skylight 21 Homes Ltd | Health & social care | 2023 |
| Skylight Homes (Desborough) Ltd | Health & social care | 2025 |
| Skylight Homes (Melton) Ltd | Health & social care | 2026 |
| Skylight Homes (Newark) Ltd | Health & social care | 2025 |
| Skylight Homes Group Limited | Financial services | 2025 |
| Skyline Developers UK Ltd | Real estate | 2017 |
| Skyroo Limited | Wholesale & retail | 2024 |
| SL Hughs Limited | Professional & scientific | 2014 |
| Slawek K Trans Ltd | Transport & logistics | 2017 |
| Sleaford Ceilings Limited | Construction | 2011 |
| Sleaford Electrical and Refrigeration Co Ltd. | Construction | 1977 |
| Sleaford Engineering Services Limited | Manufacturing | 2012 |
| Sleaford Flooring Company Limited | Construction | 1982 |
| Sleaford Garden Centre and Farm Shop Limited | Wholesale & retail | 2002 |
| Sleaford Self Store Limited | Transport & logistics | 2009 |
| Sleatech Limited | Real estate | 2008 |
| Sleek N Purple Ltd | Wholesale & retail | 2025 |
| Sleeping Giant Haulage Ltd | Transport & logistics | 2024 |
| Sleepybobo Limited | Professional & scientific | 2016 |
| Slice Instant Italian Food Company Ltd | Administrative & support | 2019 |
| Slimey Hatch Studios Ltd. | Information & communication | 2022 |
| Slimsafe Ltd | Health & social care | 2025 |
| SLJ Electrical Solutions Limited | Construction | 2023 |
| SLK Property Development Ltd | Real estate | 2025 |
| SM & SK Investments Limited | Real estate | 2019 |
| Small Beer Holdings Limited | Financial services | 2022 |
| Small Beer Limited | Wholesale & retail | 1990 |
| Small Small CIC | Health & social care | 2025 |
| Small Talk Creative CIC | Professional & scientific | 2026 |
| Small Talk Productions Ltd | Arts & recreation | 2025 |
| Smart Automotive Limited | Wholesale & retail | 2016 |
| Smart Cloud Accountants Ltd | Professional & scientific | 2017 |
| Smart Ebay Deals UK Ltd | Manufacturing | 2026 |
| Smart HEN Wholesale Ltd | Wholesale & retail | 2018 |
| Smart Resourcing Investments Ltd | Financial services | 2024 |
| Smart Resourcing Ltd | Professional & scientific | 2021 |
| Smart SHM Limited | Manufacturing | 2016 |
| Smart Stays Group Ltd | Hospitality | 2023 |
| Smart Thinking Projects Ltd | Information & communication | 2022 |
| Smart Vision UK Ltd | Information & communication | 2004 |
| Smartfert Limited | Agriculture & fishing | 2022 |
| Smartrow Ltd | Construction | 2009 |
| Smartvalve Limited | Information & communication | 2016 |
| Smash Events Ltd | Administrative & support | 2020 |
| Smash Palace Ltd | Arts & recreation | 2025 |
| SMB Decorators Ltd | Construction | 2022 |
| SMB Safety Solutions Ltd | Professional & scientific | 2024 |
| SMD Traders Limited | Wholesale & retail | 2025 |
| Smeaton Properties Limited | Real estate | 2018 |
| SMG Holdco Ltd | Financial services | 2026 |
| Smile Excellence (Central Midlands) Ltd | Health & social care | 2020 |
| SMILES4MILES IT Solutions Ltd | Financial services | 2023 |
| Smith and Wood Limited | Real estate | 2020 |
| Smith Building Solutions Ltd | Construction | 2025 |
| Smith Civils Ltd | Construction | 2015 |
| Smith Plastering Limited | Construction | 2018 |
| Smith Property Holdings Ltd | Real estate | 2023 |
| Smiths Heating & Plumbing Ltd | Construction | 2020 |
| Smokemanz Grills Ltd | Hospitality | 2025 |
| Smooth Financial Solutions Ltd | Financial services | 2017 |
| Smooth Lettings Ltd | Real estate | 2022 |
| SMS Analytical Ltd | Professional & scientific | 2014 |
| SMS Automotive Ltd | Wholesale & retail | 2025 |
| SMS Corporate Partner Limited | Professional & scientific | 2009 |
| SMT Estates Limited | Real estate | 2018 |
| Smveins Ltd | Health & social care | 2015 |
| Sn&Co Limited | Wholesale & retail | 2019 |
| Sn's Tial Food Limited | Hospitality | 2026 |