| SGR Mechanical Services Ltd | Construction | 2019 |
| Shadbolt Properties Limited | Real estate | 2020 |
| Shades Technics Limited | Manufacturing | 1991 |
| Shadeworks Studio Ltd | Manufacturing | 2026 |
| Shaftesbury Quay Management Co. Limited | Households | 1985 |
| Shamrock House RTM Company Limited | Households | 2011 |
| Shano Limited | Households | 1972 |
| Shaun Marin Limited | Professional & scientific | 2015 |
| Shawe Physio Ltd | Other services | 2015 |
| Shaws of Darwen Limited | Manufacturing | 2015 |
| Shaz (UK) Limited | Professional & scientific | 2014 |
| Shaz Contractors Limited | Professional & scientific | 2016 |
| Sheen Properties Limited | Real estate | 2021 |
| Shepherd Bush Tutors Ltd | Health & social care | 2015 |
| Shepherds Estate Agents Limited | Real estate | 2006 |
| Shepherds Estate Agents Property Holdings Limited | Real estate | 2020 |
| Sheraton Mews Management Limited | Households | 2010 |
| Sherwood Grange Residents Association Limited | Households | 1987 |
| Shevlin Marketing Ltd | Professional & scientific | 2025 |
| Shilaorganic Pakistan Ltd | Wholesale & retail | 2025 |
| Shiny Media Limited | Information & communication | 2021 |
| Shiremoor (Northumberland Park) Management Company Limited | Households | 2004 |
| Shirley Road (Acocks Green) Management Limited | Households | 2004 |
| Shopgift Limited | Wholesale & retail | 1987 |
| Shorts Management Services Limited | Professional & scientific | 2025 |
| Showroom Construction Limited | Other services | 2021 |
| Shrini Ltd | Financial services | 2026 |
| Sicilia Bella (Hoddesdon) Ltd | Hospitality | 2020 |
| Sico Consultancy Ltd | Information & communication | 2024 |
| Sigma Networks Holdings Limited | Financial services | 2019 |
| Sigma Networks Limited | Information & communication | 2000 |
| Signal Court Management Company Limited | Households | 1999 |
| Signallers Croft Management Company Limited | Households | 2026 |
| Signs 4 U Limited | Professional & scientific | 2025 |
| Silkmead Farm Estates Ltd | Real estate | 2025 |
| Silver Hill Building Services Limited | Construction | 2026 |
| Silverbird Advisory Ltd | Professional & scientific | 2024 |
| Silverfields (Raunds) Management Company Limited | Households | 2017 |
| Silverhive Limited | Information & communication | 2021 |
| Silverline Property Developments Limited | Real estate | 2006 |
| Silvertronic Limited | Manufacturing | 1986 |
| Simhaa Creations Limited | Administrative & support | 2010 |
| Simm Tronic Limited | Manufacturing | 1992 |
| Simple Choices Limited | Wholesale & retail | 2024 |
| Simply Built Ltd | Construction | 2019 |
| Simply CE & Fire Rated Product Limited | Administrative & support | 2012 |
| Simply the Pests Ltd | Administrative & support | 2019 |
| Simpson Courier Service Limited | Transport & logistics | 2003 |
| Sinclair Roofing Ltd | Real estate | 2011 |
| Sisters Keepers Christian Fellowship Limited | Other services | 2019 |
| SIX Construction Limited | Construction | 2016 |
| Siya Tech Ventures Ltd | Information & communication | 2015 |
| Sizeland & Sizeland Property Ltd | Construction | 2017 |
| Sizzle Catering Co Limited | Hospitality | 2024 |
| Sjfgas Ltd | Construction | 2019 |
| Skalene Limited | Professional & scientific | 2008 |
| Sketchd Ltd | Information & communication | 2013 |
| SKH Recruitment Ltd | Administrative & support | 2024 |
| Skylark Grange Management Company Limited | Households | 2025 |
| Skytop Limited | Real estate | 2000 |
| SLG Property Group Ltd | Real estate | 2026 |
| Slim Fluence Limited | Health & social care | 2025 |
| Sliplan Management Company Limited | Households | 1979 |
| Sloane Properties Ltd | Real estate | 2016 |
| Smart Foods Taste Limited | Hospitality | 2025 |
| Smart Inc UK Ltd | Manufacturing | 2000 |
| Smart Property Hertfordshire Ltd | Real estate | 2021 |
| Smash Bros Solutions Ltd | Hospitality | 2024 |
| Smith Rigging Ltd | Information & communication | 2021 |
| Smith's of Ongar Limited | Hospitality | 2014 |
| Smiths of Wapping Ltd | Hospitality | 2011 |
| Smooth Way Limited | Wholesale & retail | 2015 |
| Smoothie Fresh Ltd | Wholesale & retail | 2013 |
| Snaplight Flat Management Company Limited | Households | 1990 |
| Snork Tech Ltd | Professional & scientific | 2016 |
| SO Many of US Productions Ltd | Information & communication | 2024 |
| Social Spectrum Ltd | Health & social care | 2025 |
| Sole Concepts Limited | Professional & scientific | 2011 |
| Sole Developments Limited | Other services | 2013 |
| Sole Ideas Limited | Other services | 2011 |
| Solutions for Metalwork Limited | Professional & scientific | 2015 |
| Solvworks Advisory Ltd | Professional & scientific | 2026 |
| Somerby View Residents Management Company Limited | Households | 2025 |
| Sominian Investments Limited | Real estate | 2015 |
| Somvad Ltd | Information & communication | 2025 |
| Soper Square Company Limited | Households | 2005 |
| Sophie Harley London Limited | Professional & scientific | 2015 |
| Sorenzo Ltd | Professional & scientific | 2023 |
| Sorin Enterprise Ltd | Construction | 2022 |
| Soror Holdings Limited | Health & social care | 2018 |
| Soul Assets Ltd | Extraterritorial | 2026 |
| Soul Intentions Ltd | Extraterritorial | 2026 |
| Soul Seed Wellness Limited | Hospitality | 2025 |
| Sound Service U.K. Limited | Wholesale & retail | 2020 |
| South Aston Apartments Management Company Limited | Households | 1996 |
| South Gare Engineering Ltd | Professional & scientific | 2025 |
| Southern Gate (Five) Management Company Limited | Households | 1989 |
| Southern Gate (Four) Management Company Limited | Households | 1989 |
| Southfield Residents Association Limited | Households | 1983 |
| Southpaw Dog Store Limited | Wholesale & retail | 2020 |