| Spearco Construction Ltd | Construction | 2023 |
| Spearman Handyman Services Ltd | Construction | 2025 |
| Spearman Interiors Ltd | Administrative & support | 2016 |
| Special Grace & Mercy Healthcare Ltd | Health & social care | 2025 |
| Special Grace and Mercy Online Ltd | Wholesale & retail | 2024 |
| Special Grace and Mercy Properties Ltd | Construction | 2023 |
| Specialist Bodyshop Services Ltd | Wholesale & retail | 2024 |
| Specialist Care Improvement Ltd | Health & social care | 2024 |
| Specialist Recruitment Ltd | Administrative & support | 2015 |
| Spectrum Consult Properties Ltd | Real estate | 2019 |
| Spectrum Financial Advice Limited | Financial services | 2012 |
| Speedtruck Valeriu Ltd | Transport & logistics | 2017 |
| Speedy Consulting Ltd | Administrative & support | 2017 |
| Speedy Send Limited | Administrative & support | 2020 |
| Spera in DEO Consulting Limited | Information & communication | 2014 |
| Spiess Properties Limited | Real estate | 2024 |
| Spinney Pre-School Limited | Health & social care | 2024 |
| Spire Scientific and Logistics Limited | Transport & logistics | 2016 |
| Spit Productions Ltd | Information & communication | 2023 |
| Spoja Awosika Global Resources Limited | Transport & logistics | 2023 |
| Sporting Inspirations CIC | Arts & recreation | 2004 |
| SPORTING4SCHOOLS JT Limited | Education | 2025 |
| Sports 4 Newfuture Ltd | Arts & recreation | 2024 |
| Spratt's Housing Management Ltd | Households | 2012 |
| Spray Foam Removal Essex Limited | Construction | 2025 |
| Spring Hills Care Consultants Ltd | Health & social care | 2016 |
| Spring House RTM Company Limited | Households | 2017 |
| SPRING4TH Limited | Administrative & support | 2024 |
| Springfield (Blocks A,B,J,K) Management Company Limited | Households | 1995 |
| Springfield (Blocks C,D,E,F,G,H) Management Company Limited | Households | 1995 |
| Springfield D.C. Ltd | Health & social care | 2024 |
| Springflow Consulting Ltd | Real estate | 2013 |
| Sprout X Ltd | Hospitality | 2020 |
| Spurs Ltd | Other services | 2022 |
| SPZ Cars Ltd | Wholesale & retail | 2024 |
| SQ North RTM Company Limited | Households | 2011 |
| SQL DBM Solutions Ltd | Information & communication | 2012 |
| Squid Capital & Advisory Limited | Financial services | 2021 |
| Squid Group Franchise Limited | Professional & scientific | 2023 |
| Squid Systems Limited | Information & communication | 2025 |
| Squidbroker Limited | Professional & scientific | 2021 |
| Squiddy Ltd | Information & communication | 2020 |
| Squires (London Road) Management Company Limited | Households | 1996 |
| SR Letease Ltd | Real estate | 2026 |
| SRE Private Ltd | Health & social care | 2022 |
| Sririmas Thai Massage & Wellness Ltd | Other services | 2024 |
| Srisiri Thai Massage Wellness & Spa Ltd | Other services | 2024 |
| Srisuwan Thai Massage & Wellness Ltd | Other services | 2023 |
| Srivigi Ltd | Health & social care | 2021 |
| SRN Bespoke Limited | Manufacturing | 2026 |
| SRS Products Limited | Manufacturing | 1986 |
| SRU91 Ltd | Transport & logistics | 2019 |
| SS General Services Limited | Health & social care | 2016 |
| SS GP Locum Services Limited | Health & social care | 2018 |
| SS Locum Health Limited | Health & social care | 2016 |
| Ss&D Property Services Ltd | Real estate | 2024 |
| Ssara Ltd | Transport & logistics | 2020 |
| Ssddk Properties Ltd | Real estate | 2024 |
| SSE Electrical Ltd | Construction | 2013 |
| SSE Holdings Ltd | Financial services | 2017 |
| SSE Solar Energy Ltd | Extraterritorial | 2011 |
| ST Andrews Court Freehold Company Limited | Real estate | 2024 |
| ST Christopher's Place (Ruislip) Management Company Limited | Households | 2005 |
| ST Christopher’S Place (Ruislip) RTM Company Limited | Households | 2012 |
| ST Clare Hospice Trading Company Limited | Wholesale & retail | 1994 |
| ST Clare West Essex Hospice Care Trust | Health & social care | 1997 |
| ST Edmunds Estates Ltd | Administrative & support | 2018 |
| ST Lewis Staffing Services Ltd | Administrative & support | 2022 |
| ST Line Ltd | Wholesale & retail | 2025 |
| ST Mary at Hill Limited | Real estate | 2011 |
| ST Marys Vicarage Residents Management Company Limited | Households | 2018 |
| ST Pauls (Stepney) Residents Management Company Limited | Households | 2018 |
| ST Utilities Ltd | Administrative & support | 2025 |
| ST. Gregories Court Residents Association Limited | Households | 2000 |
| ST. Mark's West Essex Catholic School | Education | 2011 |
| Stable Mews Cattery Limited | Other services | 2012 |
| Stableway Properties Ltd | Real estate | 2025 |
| Stade Care Ltd | Health & social care | 2023 |
| Stafford Court Management Company (1983) Limited | Households | 1983 |
| Staidworth Homes Limited | Real estate | 2024 |
| Staidworth Limited | Professional & scientific | 2021 |
| Stainforth Consulting Limited | Information & communication | 2017 |
| Stairs on CNC Ltd | Manufacturing | 2024 |
| Stamford Yard Limited | Households | 2002 |
| Stamford Yard RTM Company Limited | Households | 2012 |
| Stamp Engineering Ltd | Professional & scientific | 2014 |
| Stand OUT Consultancy Limited | Health & social care | 2023 |
| Stanford Rivers Limited | Real estate | 2005 |
| Stanley Lodge (Islington) Limited | Households | 1999 |
| Stansted Air Lodge Ltd | Hospitality | 2024 |
| Stapletyre HCW Limited | Other services | 2019 |
| Star Care Quality Ltd | Administrative & support | 2014 |
| Star Cuts Chingford Limited | Other services | 2017 |
| Star IT Consulting Ltd | Information & communication | 2018 |
| Star Shine Tech Ltd | Wholesale & retail | 2023 |
| Starjunk Ltd | Wholesale & retail | 2020 |
| Stark Shift Ltd | Real estate | 2016 |
| Starline Roofing and Building Ltd | Construction | 2025 |
| Starling Lodge RTM Company Limited | Households | 2015 |
| Stars & Crowns Ltd | Administrative & support | 2023 |