| Sholzs Services Limited | Health & social care | 2023 |
| Shop to Go Ltd | Other services | 2018 |
| Shopdop Limited | Wholesale & retail | 2025 |
| Shopera Ltd | Wholesale & retail | 2026 |
| Shophandler Limited | Wholesale & retail | 2021 |
| Shopibuy Ltd | Wholesale & retail | 2025 |
| Shopify Solutions Ltd | Construction | 2019 |
| Shoppingwithdoja Ltd | Wholesale & retail | 2020 |
| Shopseemly Limited | Wholesale & retail | 2019 |
| Shotsbyab Ltd | Professional & scientific | 2024 |
| Showlife Ltd | Arts & recreation | 2023 |
| Shree Agate Limited | Administrative & support | 2025 |
| Shree Vinayak Exports and Imports Ltd | Wholesale & retail | 2026 |
| Shrestha Homes & Property Ltd | Real estate | 2026 |
| Shri RAM Property & Management Limited | Households | 2019 |
| Shriss Limited | Manufacturing | 2026 |
| Shub Builders Limited | Construction | 2025 |
| Shubh Kitchen and Bedroom Ltd | Manufacturing | 2025 |
| Shumi Marketing Ltd | Education | 2024 |
| SI Sempre Limited | Administrative & support | 2018 |
| SIA Global Services Ltd. | Transport & logistics | 2013 |
| Siart Scaffolding Limited | Construction | 2024 |
| SIB GAS & Plumbing Ltd | Other services | 2010 |
| SIC Pervais Magna Ltd | Wholesale & retail | 2026 |
| Sichys Media and Marketing Network Limited | Wholesale & retail | 2012 |
| Sichys Ventures Ltd | Information & communication | 2023 |
| Sidarav Limited | Construction | 2025 |
| Siddique Brothers Ltd | Wholesale & retail | 2024 |
| Sidhu Group Ltd | Construction | 2019 |
| Sidhuz Construction Ltd | Construction | 2024 |
| Siegener Sabithos London Education and Management Academy Ltd | Education | 2009 |
| Sierra Barrè Ltd | Wholesale & retail | 2025 |
| SIG Decorating Ltd | Construction | 2015 |
| Sigitas Ltd | Other services | 2013 |
| Sigma IT and Management Services Limited | Construction | 2012 |
| Sign Shine Ltd | Manufacturing | 2015 |
| Signature 187 Limited | Manufacturing | 2023 |
| Signature Property Management Services Ltd | Real estate | 2023 |
| SIGNATURE19 Ltd | Professional & scientific | 2025 |
| Signet Technology Ltd | Information & communication | 2025 |
| SIGNKRAFT3D Ltd | Wholesale & retail | 2024 |
| Signmycard Ltd | Wholesale & retail | 2025 |
| Sike Property Maintenance Limited | Construction | 2014 |
| Sile Ltd | Transport & logistics | 2021 |
| Silent Fresh Services Ltd | Administrative & support | 2025 |
| Silhouextz Ltd | Public administration | 2023 |
| Silkcare Consultancy Ltd | Professional & scientific | 2026 |
| Silva Chrome Services Limited | Transport & logistics | 2024 |
| Silva Crest Limited | Real estate | 2023 |
| Silver END Homes Limited | Construction | 2009 |
| Silvera Glamour Luxury Ltd | Wholesale & retail | 2024 |
| Silvercrest Data Services Ltd | Information & communication | 2025 |
| Silverdean Limited | Construction | 2017 |
| Silvernest Investments Limited | Real estate | 2024 |
| Silvys Shiny Service Ltd | Administrative & support | 2025 |
| Sima Transport Ltd | Transport & logistics | 2016 |
| Simas Transport Ltd | Transport & logistics | 2022 |
| Simbo Properties Limited | Financial services | 2020 |
| Simeon Daniels Properties Ltd | Real estate | 2025 |
| Simeonbeth Care Limited | Transport & logistics | 2022 |
| Simhans Ltd | Health & social care | 2024 |
| Simi Green Limited | Administrative & support | 2021 |
| Simi-Wonu Healthcare Ltd | Health & social care | 2023 |
| Simion Interiors Ltd | Construction | 2023 |
| Simky Fried Chicken Ltd | Hospitality | 2026 |
| Simo Meats UK Ltd | Wholesale & retail | 2023 |
| Simon's DJ Ltd | Arts & recreation | 2026 |
| Simona Miron Driving School Ltd | Education | 2022 |
| Simple Accident Holdings Limited | Financial services | 2010 |
| Simple Claims Limited | Administrative & support | 2004 |
| Simple Dayout Limited | Administrative & support | 2010 |
| Simple Delicacy Limited | Health & social care | 2018 |
| Simple East (Holdings) Limited | Administrative & support | 2009 |
| Simple Self Drive Ltd | Transport & logistics | 2004 |
| Simple Settings Childrens Home Ltd | Health & social care | 2024 |
| Simple Settings Ltd | Health & social care | 2022 |
| Simple Tech Solutions (UK) Ltd | Information & communication | 2013 |
| Simpley Organic Limited | Wholesale & retail | 2025 |
| Simply Checks Limited | Wholesale & retail | 2014 |
| Simply Global Group Ltd | Information & communication | 2025 |
| Simply Mamycook Ltd | Hospitality | 2025 |
| Simply Quran School Limited | Education | 2014 |
| Simplythato Limited | Administrative & support | 2011 |
| Simya Logistics Ltd | Transport & logistics | 2023 |
| Sinachi Properties Limited | Real estate | 2026 |
| Sinani Education Ltd | Education | 2025 |
| Sinani Pool Table Ltd | Hospitality | 2023 |
| Sincere Care Ltd | Health & social care | 2008 |
| Sindons Limited | Professional & scientific | 2020 |
| Singh Bricklayers (London) Ltd | Construction | 2024 |
| Singh Design & Build Limited | Construction | 2016 |
| Singh Doors and Windows Ltd | Construction | 2023 |
| Singh Properties Dagenham Ltd | Other services | 2017 |
| Singh Property and Contruction Limited | Construction | 2019 |
| Singla Developers Limited | Construction | 2025 |
| SIR Shine Alot Ltd | Other services | 2015 |
| Sirac Foods Limited | Hospitality | 2021 |
| Sircioc Limited | Construction | 2015 |
| Sircu Services Ltd | Construction | 2025 |
| Sireesha Solutions Ltd | Information & communication | 2017 |