| Saneveny Ltd | Real estate | 2019 |
| Sano Property Holdings Limited | Other services | 2025 |
| Sanrizz (Guildford) Limited | Other services | 2004 |
| Sanrizz (Knightsbridge) Limited | Other services | 2001 |
| Sanrizz (ST Albans) Limited | Other services | 2005 |
| Sanrizz Academy Limited | Education | 2010 |
| Sanrizz Properties Limited | Real estate | 1985 |
| Sanvi Solutions Limited | Information & communication | 2019 |
| Saol Innovative Creations Ltd | Professional & scientific | 2017 |
| Sapicons Limited | Information & communication | 2010 |
| Sapphire & Co Ltd | Other services | 2010 |
| Sappho Bar Ltd | Hospitality | 2022 |
| Saribugday Limited | Hospitality | 2025 |
| Sarynakey UK Ltd | Administrative & support | 2019 |
| SAS Curries Limited | Hospitality | 2024 |
| SAS Waste Management Ltd | Water & waste | 2020 |
| Saso London Ltd | Other services | 2022 |
| Sathya SAI Services Limited | Information & communication | 2009 |
| Satpd Ltd | Real estate | 2026 |
| Saturn Owners Club Ltd | Professional & scientific | 2021 |
| Saucy Salads Ltd | Hospitality | 2026 |
| Savoury Box Ltd | Manufacturing | 2023 |
| Savoy Finance Limited | Administrative & support | 2020 |
| Saxon's Hospitality Ltd | Health & social care | 2018 |
| SB Electrical & Trade Services Limited | Wholesale & retail | 2024 |
| SCA International Limited | Professional & scientific | 2019 |
| SCG (GB) Limited | Professional & scientific | 2013 |
| SCH Consultancy Limited | Professional & scientific | 2018 |
| Schlesien Limited | Professional & scientific | 2012 |
| Scientific Project Management Ltd | Professional & scientific | 2025 |
| Scimitar Estates Ltd | Real estate | 1987 |
| SCL Projects Ltd | Other services | 2024 |
| Scott House Management (Hertford) Limited | Households | 2022 |
| Scott Keyes Limited | Extraterritorial | 2015 |
| Sculpt House Reformer Ltd | Other services | 2025 |
| SD Rock Ltd | Arts & recreation | 2024 |
| Seaess Investments Limited | Real estate | 2023 |
| Seaton Contracts Limited | Real estate | 2016 |
| Second Spell Ltd | Education | 2022 |
| Secura Real Estate Limited | Real estate | 2024 |
| Seditionaries Limited | Other services | 2005 |
| Segar Properties (Hyde Park) Limited | Real estate | 1962 |
| SEL Makeup Limited | Other services | 2023 |
| Select Roof & Building Ltd | Construction | 2022 |
| Self Made Girl Boss Ltd | Administrative & support | 2020 |
| Sels Kitchen Ltd | Wholesale & retail | 2025 |
| SEN Parent Mentor Limited | Education | 2025 |
| Sendmore Limited | Other services | 2004 |
| Senera One Global Ltd | Wholesale & retail | 2026 |
| Sensa Services Ltd | Construction | 2009 |
| Sensible Data UK Ltd | Wholesale & retail | 2024 |
| Sentinel 7 Ltd | Other services | 2016 |
| Sentinel Planning Limited | Administrative & support | 2012 |
| Seogene Services LLP | | 2023 |
| Septest Limited | Manufacturing | 2022 |
| Seraph Industries Ltd | Financial services | 2020 |
| Serenitea Social Ltd | Health & social care | 2025 |
| Service Source Europe Ltd | Wholesale & retail | 2018 |
| SET Property Company Limited | Construction | 2020 |
| Seven 12 Associates Limited | Real estate | 2024 |
| Seven Degrees Retail Ltd | Hospitality | 2024 |
| Seven Property Portfolio Ltd | Real estate | 2021 |
| Seventh 12TH Limited | Financial services | 2022 |
| Seymour Investments Limited | Real estate | 2006 |
| SG Wealth LLP | | 2026 |
| SH Property Assets Limited | Real estate | 2026 |
| Shake N Bake Potters Bar Ltd | Hospitality | 2022 |
| Shaldon Investments Limited | Real estate | 1987 |
| Shambi Property Developments Ltd | Real estate | 2025 |
| Shapa Ltd | Wholesale & retail | 2024 |
| Sharma Assets Ltd | Real estate | 2025 |
| Sharma Mansions Ltd | Households | 2025 |
| Sharpline Developments Limited | Real estate | 2018 |
| Sharpline Electrical Limited | Manufacturing | 2023 |
| Sharpline Solutions Limited | Other services | 2017 |
| Shearwater Built Asset Consultancy Ltd | Professional & scientific | 2016 |
| Sherfield Investments Limited | Administrative & support | 2021 |
| SHERINGHAM1 Ltd | Real estate | 2016 |
| Sherwood Equestrian Limited | Wholesale & retail | 2001 |
| Sheval Services Ltd | Real estate | 2018 |
| Shift Healthcare Ltd | Health & social care | 2020 |
| Shine & Design Ltd | Wholesale & retail | 2019 |
| Shinecraft Solutions Co Ltd | Professional & scientific | 2025 |
| Shinex Ltd | Information & communication | 2012 |
| Ship-It-Xpress Solutions Ltd | Transport & logistics | 2018 |
| Shirley Watson Consultancy Limited | Professional & scientific | 2014 |
| Shnatz Ltd | Professional & scientific | 2011 |
| Shoe Theory Limited | Manufacturing | 2017 |
| Shot Girling Limited | Administrative & support | 2021 |
| Shrieking Violet Limited | Wholesale & retail | 2002 |
| Side Chase Ltd | Construction | 2026 |
| Signage Studio Ltd | Manufacturing | 2021 |
| Silkz Limited | Real estate | 2019 |
| Silver Beech Limited | Other services | 2026 |
| Silver Capital Advisory Limited | Professional & scientific | 2018 |
| Silver Heights Properties Ltd | Real estate | 2017 |
| Silver Homes Investments Limited | Real estate | 2015 |
| Silver Homes Management Limited | Households | 2025 |
| Silver Ridge Limited | Administrative & support | 2010 |
| Silver Walk Freehold Limited | Real estate | 2000 |