| Silk Capital Limited | Financial services | 2016 |
| Silk Route Properties Limited | Real estate | 2022 |
| Silkin House Limited | Real estate | 2025 |
| Silvaro Ltd | Manufacturing | 2015 |
| Silver Brick Properties Limited | Real estate | 2010 |
| Silver Lining Fostering Ltd | Health & social care | 2017 |
| Silver Property Ltd | Construction | 2025 |
| Silver Robin Publishing Ltd | Information & communication | 2026 |
| Silver Superstore Limited | Wholesale & retail | 2016 |
| Silverblade Limited | Information & communication | 2013 |
| Silvercoin Estates Limited | Real estate | 2018 |
| Silverdale Care Limited | Health & social care | 2017 |
| Silverdale Software Services Limited | Information & communication | 1989 |
| Silverline Developments Limited | Real estate | 2021 |
| Silverline Real Estates Limited | Real estate | 2022 |
| Silvertech Solutions Limited | Information & communication | 2019 |
| SIM Distributors Ltd | Wholesale & retail | 2020 |
| Simar Hothi Ltd | Transport & logistics | 2026 |
| Simarconstructions Limited | Construction | 2024 |
| Simcroft Care Ltd | Health & social care | 2025 |
| Simi Fabrics Ltd | Wholesale & retail | 2021 |
| Simi Shallon Ltd | Health & social care | 2023 |
| Simoh Global Ltd | Wholesale & retail | 2025 |
| Simon & C Limited | Construction | 2017 |
| Simple Accounting Services Ltd | Professional & scientific | 2023 |
| Simple Sanitaryware and Plumbing Trading AS Simple Sanitaryware Ltd | Wholesale & retail | 2024 |
| Simply Accounts (UK) Ltd | Administrative & support | 2013 |
| Simply Customise Limited | Wholesale & retail | 2025 |
| Simply the Right Properties Ltd | Real estate | 2021 |
| SIMPLYBUILD4YOU Limited | Construction | 2018 |
| Simran Property Limited | Real estate | 2016 |
| Simran UK Investments Ltd | Real estate | 2023 |
| Simrans Enterprises (UK) Limited | Wholesale & retail | 2016 |
| Simrantandon Limited | Construction | 2025 |
| Simrit Development Ltd | Construction | 2018 |
| Sims Gold Limited | Manufacturing | 2025 |
| Sims Office Cleaning Services Limited | Households | 2005 |
| Simta Capital Limited | Real estate | 2017 |
| Simta Limited | Financial services | 2018 |
| Sinclair Harris Ltd | Construction | 2025 |
| Sindia Life Coach Ltd | Other services | 2019 |
| Singcore Ltd | Wholesale & retail | 2023 |
| Singh & Kaur Estate Agents Ltd | Real estate | 2022 |
| Singh & LEE Ltd | Hospitality | 2018 |
| Singh & Shina Limited | Real estate | 2025 |
| Singh Baljinder Ltd | Transport & logistics | 2025 |
| Singh Bedrooms and Kitchens Limited | Manufacturing | 2020 |
| Singh Brothers Express Ltd | Wholesale & retail | 2023 |
| Singh Brothers Services Limited | Administrative & support | 2024 |
| Singh Developers Ltd | Construction | 2015 |
| Singh Distributions Ltd | Wholesale & retail | 2021 |
| Singh Empire Ltd | Real estate | 2026 |
| Singh Essential Limited | Wholesale & retail | 2022 |
| Singh Fitted Furniture Ltd | Manufacturing | 2025 |
| Singh Food and Wine Limited | Wholesale & retail | 2014 |
| Singh Food N Wines London Limited | Wholesale & retail | 2025 |
| Singh Kitchens &Bedrooms Ltd | Manufacturing | 2024 |
| Singh Painters Limited | Construction | 2025 |
| Singh Properties Ltd | Real estate | 2015 |
| Singh Property Investments Ltd | Construction | 2019 |
| Singh Repair & FIX Ltd | Other services | 2024 |
| Singh Services Ltd | Construction | 2015 |
| Singh Wardrobes Limited | Manufacturing | 2024 |
| Singh's Corner UK Ltd | Real estate | 2018 |
| SINGH4CARS Ltd | Wholesale & retail | 2025 |
| Singhal UK Ltd | Agriculture & fishing | 2014 |
| Singhnature Restaurant Limited | Hospitality | 2019 |
| Singhs Bakery Ltd | Hospitality | 2022 |
| Singhs Construction Ltd | Construction | 2024 |
| Singhs Food N Wine Limited | Wholesale & retail | 2025 |
| Singhs Grover Properties Ltd | Real estate | 2021 |
| Singhs Investment Firm Ltd | Real estate | 2022 |
| Singhs Property Investment Ltd | Real estate | 2026 |
| SIP Couriers Ltd | Transport & logistics | 2019 |
| Sipl (UK) Ltd | Real estate | 2020 |
| Sira Estates Limited | Real estate | 2020 |
| Siragugal C.I.C. | Health & social care | 2025 |
| Siraj Haulage Limited | Transport & logistics | 2025 |
| Sister Films Ltd | Information & communication | 2023 |
| Sisters Group Limited | Hospitality | 2018 |
| Sita Pure Wash Launderette Ltd | Administrative & support | 2025 |
| Sita Staffing Limited | Hospitality | 2017 |
| Sitad Consulting Limited | Information & communication | 2010 |
| Sitc Ltd | Information & communication | 2021 |
| Site Sphere Ltd | Information & communication | 2022 |
| Siteway Services Ltd | Administrative & support | 2026 |
| Sithara Films Limited | Information & communication | 2023 |
| Sizl Consortium Private Limited | Transport & logistics | 2020 |
| Sizzling Pans Ltd | Hospitality | 2024 |
| SJ Carroll Consulting Limited | Information & communication | 2013 |
| SJ Constructions UK 1 Ltd | Construction | 2023 |
| SJ Contractor London Ltd | Construction | 2018 |
| SJ LOG Limited | Transport & logistics | 2025 |
| SJ Roofing Group Ltd | Construction | 2024 |
| SJ Ventures Ltd | Hospitality | 2023 |
| SJG Pest Control Ltd | Administrative & support | 2024 |
| Sjosan Builders Ltd | Construction | 2022 |
| SJR Quality Cars Ltd | Wholesale & retail | 2013 |
| SJT Masterclass Ltd | Education | 2021 |
| SK Dhaliwal Limited | Real estate | 2021 |