| Scott Art Limited | Professional & scientific | 2018 |
| Scrowe Limited | Households | 2020 |
| Scrowe Properties Limited | Real estate | 2025 |
| Scsl Properties Limited | Real estate | 2021 |
| Sea-Change Projects Limited | Other services | 2007 |
| Sea-Dek Limited | Other services | 2007 |
| Seabridge Media Ltd | Wholesale & retail | 2025 |
| Seaford Glass Ltd | Extraterritorial | 2025 |
| Seagull Marketing & Consulting Limited | Professional & scientific | 2016 |
| Seasons END Air Conditioning Ltd | Energy | 2017 |
| Secret Hamper Ltd | Wholesale & retail | 2016 |
| Seewall Limited | Professional & scientific | 2005 |
| Segrave & Pocknell Limited | Professional & scientific | 2026 |
| Seismicc Limited | Education | 2009 |
| Select a Plan Electrical Services Limited | Other services | 2007 |
| Self & Co | | 1997 |
| SEN Mortgage Solutions Ltd | Financial services | 2023 |
| SEO - Sels Limited | Professional & scientific | 2004 |
| SET Scaffolding Ltd | Construction | 2026 |
| Sexy Beers Limited | Professional & scientific | 2005 |
| Sexy Lagers Limited | Professional & scientific | 2005 |
| Sfrogers Limited | Construction | 2014 |
| Shagal Limited | Real estate | 2017 |
| Shakespeare Property Limited | Real estate | 2017 |
| Shane Anderson Construction Limited | Construction | 2025 |
| Shanghai Lijiaqi Machinery Trading Co., Ltd. | Administrative & support | 2023 |
| Shardview Ltd | Professional & scientific | 2014 |
| Shaun Baker Car Care Ltd | Wholesale & retail | 2015 |
| She-Dee Ltd | Wholesale & retail | 2006 |
| Sheldon Bishop Limited | Real estate | 2009 |
| Shepherd Engineering (Anglian) Limited | Other services | 2007 |
| Shireen Limited | Wholesale & retail | 2021 |
| Shorelands Financial Services Ltd | Professional & scientific | 2020 |
| Short Term Accommodation Ltd | Real estate | 2026 |
| Showcase Plastics Ltd | Construction | 2019 |
| Showcase Windows and Doors Ltd | Construction | 2008 |
| Shree London Ltd | Wholesale & retail | 2020 |
| Shrublands Bentley Ltd | Real estate | 2025 |
| Sightline Limited | Financial services | 2025 |
| Sigma Trading Co., Ltd | Administrative & support | 2023 |
| Sign and Design Services Limited | Professional & scientific | 2017 |
| Signal Speak UP Ltd | Administrative & support | 2023 |
| Silicon Alley Limited | Wholesale & retail | 1994 |
| Silkworm Store Limited | Manufacturing | 2023 |
| Silky Properties Ltd | Real estate | 2023 |
| Silverlight Security Limited | Administrative & support | 2022 |
| Simon Frazer Limited | Information & communication | 2025 |
| Singam & Co Limited | Professional & scientific | 1997 |
| Sirius Development Ltd | Administrative & support | 2019 |
| Siskin Sales Ltd | Wholesale & retail | 2024 |
| Siskin Tech Ltd | Information & communication | 2023 |
| Siti Ltd | Real estate | 2022 |
| SIX Consulting Ltd | Professional & scientific | 2011 |
| SJ Acquisition Holdings Ltd | Financial services | 2024 |
| SJA Electrical Services Ltd | Construction | 2022 |
| SJE Holdingco Limited | Financial services | 2026 |
| SJE Investments Limited | Construction | 2026 |
| SJH Electrical Ltd | Construction | 2023 |
| SJM Network Services Limited | Administrative & support | 2020 |
| Skc-Trade Ltd | Other services | 2020 |
| Skills Coach Ltd | Administrative & support | 2020 |
| Skin-Rg Ltd | Manufacturing | 2011 |
| Skippers Ground Maintenance Limited | Administrative & support | 2015 |
| Skywalker Ventures Ltd | Professional & scientific | 2017 |
| SL JAY Commercial Ltd | Real estate | 2024 |
| SL JAY Investments Limited | Real estate | 2016 |
| Slater Galpin Passive Fire Protection Ltd | Public administration | 2022 |
| Slatwall Warehouse Limited | Extraterritorial | 2010 |
| Sleepy in My Teepee Limited | Arts & recreation | 2025 |
| Slice (Chelmsford) Ltd | Hospitality | 2011 |
| Slide-A-Glide Limited | Manufacturing | 2003 |
| Slim and Trim (Witham) Limited | Arts & recreation | 2005 |
| Slotaspect Property Management Limited | Real estate | 1998 |
| Small Waste Limited | Administrative & support | 2011 |
| Smallfields Commercial Limited | Professional & scientific | 2023 |
| Smallfields Estates Limited | Construction | 2021 |
| Smallfields Holdings Limited | Financial services | 2024 |
| Smart Auto Services Limited | Professional & scientific | 1995 |
| Smart Vending Solutions Ltd | Wholesale & retail | 2022 |
| Smartweb Publishers Ltd | Administrative & support | 2016 |
| SMB Booster Ltd | Administrative & support | 2025 |
| SMB Electrical Contractors Limited | Construction | 2009 |
| Smiths of Essex Ltd | Wholesale & retail | 2016 |
| Smoke Vent Limited | Manufacturing | 2013 |
| Smoke Vent Response Limited | Manufacturing | 2022 |
| Smokehouse Yard Freehold Limited | Real estate | 2024 |
| SMW Homes Limited | Real estate | 2016 |
| Snpshot Media Ltd | Professional & scientific | 2025 |
| SOC & SON Ltd | Transport & logistics | 2019 |
| Soda Cellar Limited | Wholesale & retail | 2017 |
| Sofis Limited | Manufacturing | 1985 |
| Soft Play Haus Ltd | Arts & recreation | 2025 |
| Solarin Capital Ltd | Administrative & support | 2021 |
| Solitaire (Essex) Limited | Real estate | 2026 |
| Solitaire Plumbing and Heating Limited | Construction | 2015 |
| Solutions for Sport Limited | Arts & recreation | 2026 |
| Sophies Tea Rooms Ltd | Hospitality | 2025 |
| Soul Priority Ltd | Health & social care | 2023 |
| Sound and Vision Technology Limited | Professional & scientific | 1994 |
| South East Real Estate Ltd | Real estate | 2023 |