| Shivaamsh Consulting Limited | Information & communication | 2024 |
| Shivansfood Ltd | Hospitality | 2026 |
| Shivasphere UK Ltd | Wholesale & retail | 2024 |
| Shivrani Properties Ltd | Real estate | 2026 |
| Shomit Mitter Ltd | Health & social care | 2012 |
| Shopnoor Ltd | Wholesale & retail | 2025 |
| Shot Supplements Limited | Health & social care | 2026 |
| Show Scenery Ltd | Manufacturing | 2020 |
| Shreada Ltd | Information & communication | 2020 |
| Shree Krupa Limited | Professional & scientific | 2022 |
| Shru London Limited | Other services | 2023 |
| Shruthilaya Ltd | Other services | 2020 |
| Shuangman Industrial Co., Ltd | Wholesale & retail | 2023 |
| SHY Shot Ltd | Professional & scientific | 2024 |
| SI Fashion Ltd | Wholesale & retail | 2026 |
| Sibnix Limited | Wholesale & retail | 2026 |
| Siddle Software Limited | Information & communication | 2025 |
| Sidi Property Investment Limited | Construction | 2022 |
| Sidra Domiciliary Care Limited | Health & social care | 2022 |
| Sieben & Co Ltd | Information & communication | 2024 |
| Sierra Sports Development Limited | Arts & recreation | 2015 |
| Sifanoor Investments Limited | Real estate | 2018 |
| Sifanoor Property (Management) Limited | Households | 2016 |
| Sigaram Limited | Wholesale & retail | 2022 |
| Signal and Rail Admin Services Limited | Professional & scientific | 2021 |
| Signal Technology Limited | Professional & scientific | 1996 |
| Signature Chauffeur Hire (London) Ltd | Transport & logistics | 2008 |
| Significant Figures Ltd | Professional & scientific | 2014 |
| Signlink Limited | Information & communication | 2013 |
| Signs Studio (London) Ltd | Construction | 2009 |
| Siguan Ltd | Professional & scientific | 2026 |
| Silva Cleaning Limited | Administrative & support | 2003 |
| Silverback Photography and Logistics Ltd | Transport & logistics | 2019 |
| Silverstone CHP LP | | 2025 |
| Silvertree Accounting Services Ltd | Professional & scientific | 2012 |
| Silvertree Business Services Ltd | Professional & scientific | 2015 |
| Silvertree Properties Ltd | Real estate | 2022 |
| Simba Construction and Design Ltd | Construction | 2025 |
| Simcox Investments Limited | Real estate | 2015 |
| Simeogieme Ltd | Manufacturing | 2008 |
| Simi Food & Wine Ltd | Wholesale & retail | 2025 |
| Simon & Co Accountants Ltd. | Professional & scientific | 2007 |
| Simple Investments Ltd | Hospitality | 2016 |
| Simple Science Limited | Information & communication | 1997 |
| Simplex Capital Ltd | Real estate | 2016 |
| Sinai Properties Ltd | Wholesale & retail | 2025 |
| Sinoworld Trading Ltd | Wholesale & retail | 2026 |
| Sinu Events Hub Limited | Professional & scientific | 2018 |
| Siorc Group Ltd | Arts & recreation | 2020 |
| Sipson Caravans Limited | | 1963 |
| Sira and Sons Ltd | Construction | 2019 |
| Sirius Homes Ltd | Real estate | 2021 |
| Sister Mountain Ltd | Professional & scientific | 2022 |
| Sitaram IT Services Limited | Information & communication | 2018 |
| SIX Savoy Court Limited | Other services | 1985 |
| SJ Business Consultancy Ltd | Information & communication | 2017 |
| SJ Shar Limited | Information & communication | 2019 |
| SJC Eurasia Ltd | Professional & scientific | 2019 |
| SJZ Business Ltd | Wholesale & retail | 2024 |
| SK Acton Limited | Financial services | 2022 |
| SK Banbury Limited | Transport & logistics | 2002 |
| SK Bath Limited | Financial services | 2021 |
| SK Canterbury 1 Limited | Financial services | 2021 |
| SK Consulting Properties Ltd | Real estate | 2024 |
| SK Consulting Solutions Ltd | Professional & scientific | 2012 |
| SK Dynamics Ltd | Transport & logistics | 2020 |
| SK Enterprise JV Limited | Financial services | 2023 |
| SK Frome Limited | Transport & logistics | 2014 |
| SK Heathrow Limited | Financial services | 2020 |
| SK JV 5 Holdco Limited | Transport & logistics | 2006 |
| SK JV 5 Midco Limited | Transport & logistics | 2011 |
| SK JV Bidco Limited | Financial services | 2022 |
| SK Leyton Limited | Real estate | 2023 |
| SK Propco Limited | Real estate | 2021 |
| SK Ramsgate Limited | Financial services | 2026 |
| SK Salisbury Limited | Transport & logistics | 2020 |
| SK Wednesbury Limited | Transport & logistics | 2011 |
| SK West Brom Limited | Financial services | 2022 |
| Skallides Ltd | Manufacturing | 2025 |
| Skangalaxy Ltd | Information & communication | 2025 |
| Skanwave Limited | Information & communication | 2023 |
| Skellywag Limited | Professional & scientific | 2009 |
| Skerry 2 Ltd | Construction | 2017 |
| Skill X Academy Ltd | Education | 2025 |
| Skin Love & Care Ltd | Health & social care | 2025 |
| Skincarnate Ltd | Wholesale & retail | 2019 |
| Skladem Ecom Ltd | Wholesale & retail | 2025 |
| SKM Contracting Ltd | Construction | 2015 |
| SKS Universal Ltd | Hospitality | 2024 |
| Skvp Ruislip Ltd | Hospitality | 2024 |
| Sky 2 Sea Limited | Extraterritorial | 2001 |
| Skyhawk Group Ltd. | Administrative & support | 2020 |
| Skyline Four Ltd | Other services | 2022 |
| Skyline Global Solutions Limited | Information & communication | 2013 |
| Slant Sustainable Technologies Ltd | Manufacturing | 2023 |
| Slawomir Galka Building & Maintenance Services Ltd | Construction | 2020 |
| Slgk Ltd | Arts & recreation | 2022 |
| SLR Estates Ltd | Real estate | 2024 |
| SM Advisory Services Limited | Professional & scientific | 2023 |
| Smakai Construction Ltd | Construction | 2019 |