| Sky Bull Ltd | Manufacturing | 2014 |
| Sky Electrics Ltd | Construction | 2020 |
| Sky Nails Bars Limited | Other services | 2014 |
| Skydgs Limited | Transport & logistics | 2024 |
| Skylight Business Limited | Administrative & support | 2019 |
| Skylight Olive Limited | Health & social care | 2014 |
| Skyline Future Ltd | Wholesale & retail | 2020 |
| Skyline Shopfitters Limited | Construction | 2018 |
| Skyward Commercial Ltd | Real estate | 2026 |
| Slavbuilders Ltd | Construction | 2023 |
| Sleek & Tidy Ltd | Administrative & support | 2025 |
| SLH Motor Parts Ltd | Wholesale & retail | 2018 |
| Slievo Limited | Administrative & support | 2011 |
| Slipform Technology Ltd | Construction | 2024 |
| SLK Automotive Ltd | Wholesale & retail | 2021 |
| SLK Ventures Ltd | Wholesale & retail | 2024 |
| Sloan Electrical Telecom and Data Limited | Energy | 2017 |
| Slomandaz Engineering Ltd | Construction | 2026 |
| Slywark IT Services Limited | Information & communication | 2015 |
| SMA Recruitment Ltd | Transport & logistics | 2024 |
| Smak Ltd | Administrative & support | 2026 |
| Smallsquad Ltd | Information & communication | 2020 |
| Smart Asbestos Solution Limited | Construction | 2017 |
| Smart Builders & Decorators Ltd | Construction | 2021 |
| Smart Construction & Build Ltd | Construction | 2018 |
| Smart Energy Essex Limited | Construction | 2019 |
| Smart EV Autos, Parts & Finance Ltd | Wholesale & retail | 2025 |
| Smart Sealants Ltd | Construction | 2025 |
| Smart Wheels Autos Ltd | Wholesale & retail | 2025 |
| Smartadrigeo Ltd | Manufacturing | 2025 |
| Smartsmales Limited | Wholesale & retail | 2025 |
| Smartytransport Ltd | Transport & logistics | 2025 |
| Smatra Group Limited | Professional & scientific | 2008 |
| SME Corporate Finance Limited | Professional & scientific | 1999 |
| SMG Homes Ltd | Construction | 2025 |
| Smily Signature Designs International Ltd | Construction | 2024 |
| Smith a T Limited | Wholesale & retail | 2019 |
| Smith FRA Limited | Manufacturing | 2024 |
| Smoothees Limited | Manufacturing | 2020 |
| Snape Computers Limited | Information & communication | 1983 |
| Snappy Schoolwear Limited | Wholesale & retail | 2019 |
| Snaresbrook Grange Management Company Limited | Households | 1997 |
| Sneddon Smart Solutions Ltd | Information & communication | 2024 |
| Snnc Ltd | Transport & logistics | 2021 |
| SO Creations Limited | Wholesale & retail | 2023 |
| Soare Logistic Limited | Transport & logistics | 2019 |
| Soccer Sphere Limited | Wholesale & retail | 2025 |
| Social Work Bridges Enterprise Limited | Education | 2016 |
| Soft Diamond Limited | Hospitality | 2017 |
| Soft Lemons Golf Ltd | Wholesale & retail | 2023 |
| Soft Nova Innovation Ltd | Information & communication | 2025 |
| Softcare Solutions Ltd | Health & social care | 2024 |
| Soga Investments Limited | Real estate | 2007 |
| Sohail Best Trading Ltd | Wholesale & retail | 2020 |
| Solace House Limited | Real estate | 2020 |
| Solar Simplicity Limited | Administrative & support | 2021 |
| Solarxpert Ltd | Energy | 2024 |
| Solase Consultancy Limited | Professional & scientific | 2005 |
| Solei Construction Ltd | Construction | 2023 |
| Solera Ltd | Construction | 2021 |
| Solerock Ltd | Construction | 2019 |
| Solomon Oduh Health Care Ltd | Health & social care | 2021 |
| Solomon Says Consulting Ltd | Information & communication | 2018 |
| Somax Enterprises Ltd | Health & social care | 2013 |
| Somed Medical Limited | Health & social care | 2009 |
| Sonis Properties Ltd | Real estate | 2023 |
| SONYA1974 Ltd | Health & social care | 2014 |
| SOS Heating and Maintenance Services Ltd | Construction | 2024 |
| Source to Safety Limited | Information & communication | 2012 |
| South African Kitchen Ltd | Hospitality | 2021 |
| South Coast Private Hire Limited | Wholesale & retail | 2014 |
| South Eastern Developments Limited | Real estate | 2024 |
| South Eastern Services Ltd | Households | 2025 |
| South West Essex Community Education Trust Limited | Education | 2011 |
| Southern Plant Hire Ltd | Administrative & support | 2015 |
| Sovereign Security London Ltd | Administrative & support | 2019 |
| SOW Property Services Ltd | Real estate | 2024 |
| Sowa Pharma Limited | Wholesale & retail | 2024 |
| SP Deliveries Ltd | Transport & logistics | 2026 |
| SP Omega Services Ltd | Construction | 2017 |
| SP Protection Limited | Administrative & support | 2003 |
| Spar Management Ltd | Arts & recreation | 2023 |
| SPARK4U Electrical Ltd | Wholesale & retail | 2023 |
| Sparks Mortgages Ltd | Financial services | 2023 |
| Sparks PAT Testing Limited | Professional & scientific | 2007 |
| Spartan Metal Recycling Limited | Water & waste | 2021 |
| Sparx Transport Ltd | Transport & logistics | 2025 |
| Special Assets & Services Ltd | Households | 2017 |
| Specialised Engines Limited | Wholesale & retail | 1980 |
| Spectracore Solutions Limited | Information & communication | 2025 |
| Spectrum Commercial Bodyshop Limited | Wholesale & retail | 2017 |
| Spectrum Vehicle Repairers (Essex) Limited | Wholesale & retail | 2019 |
| Spectrum Vehicle Repairers (Kent) Limited | Wholesale & retail | 2019 |
| Spectrum Vehicle Repairers Bodyshop Group Limited | Financial services | 2019 |
| Speed a Trans Ltd | Transport & logistics | 2016 |
| Spexia Services Limited | Information & communication | 2024 |
| Spice HUT Grays Ltd | Hospitality | 2025 |
| Spicy Top Ltd | Hospitality | 2020 |
| Spinns Social Care Consulting Ltd | Administrative & support | 2016 |
| Spiral-Red Limited | Water & waste | 2015 |