| Shreelakshmikantam Limited | Manufacturing | 2023 |
| Shreoshi Lettings Limited | Real estate | 2024 |
| Shri Pragathi Consultancy Ltd | Information & communication | 2018 |
| Shri Vatsa Associates Limited | Real estate | 2022 |
| Shri Vatsa IT Associates Ltd | Information & communication | 2012 |
| Shridauji Limited | Real estate | 2023 |
| Shruti Collective CIC | Education | 2025 |
| SHU Aromi Ltd | Hospitality | 2019 |
| SHU Consulting Limited | Professional & scientific | 2023 |
| Shumilov Limited | Health & social care | 2020 |
| Shutter Brothers Limited | Manufacturing | 2025 |
| Shutter Town Ltd | Wholesale & retail | 2018 |
| Sidcup Catering Limited | Hospitality | 2025 |
| Sidd IT Consultancy Ltd | Information & communication | 2011 |
| Siddall Developments Limited | Households | 2020 |
| Siddhi Consultancy Ltd | Professional & scientific | 2017 |
| Siddhi V Limited | Health & social care | 2020 |
| Siddhi Vinayak Homes Limited | Real estate | 2021 |
| Sidhu Construction Services Limited | Construction | 2016 |
| Sidhu Investment Properties Ltd | Real estate | 2023 |
| Sigsec Kent Ltd | Construction | 2022 |
| SIH Solutions Ltd | Professional & scientific | 2011 |
| Sila Investments Limited | Real estate | 2015 |
| Silestia Ltd | Health & social care | 2022 |
| Silk Alternative Finance Ltd | Construction | 2021 |
| Silodia Limited | Real estate | 2019 |
| Silve Construction Limited | Construction | 2019 |
| Silver Breeze One Ltd | Professional & scientific | 2015 |
| Silver Housing PVT Ltd | Real estate | 2025 |
| Silver Peptides Ltd | Wholesale & retail | 2026 |
| Silver Sunrise Services Ltd | Professional & scientific | 2022 |
| Sima Sweets & Olives Ltd | Professional & scientific | 2019 |
| Simon & Co Accountancy Ltd | Professional & scientific | 2014 |
| Simon & Co Accountancy Services LLP | | 2022 |
| Simon James Grounds Maintenance Ltd | Construction | 2021 |
| Simon's Home Ltd | Real estate | 2022 |
| Simple Secure Storage Limited | Transport & logistics | 2024 |
| Simply Sushi UK Ltd | Hospitality | 2023 |
| Simpson's Place Management Company Limited | Households | 1999 |
| SIN Developments Ltd | Real estate | 2021 |
| Sinclair Court (Freehold) Company Ltd | Real estate | 2013 |
| Sinclair Court Management (Beckenham) Limited | Households | 1971 |
| Sine Screen Ltd | Information & communication | 2022 |
| Sinfield Supplies Ltd | Wholesale & retail | 2020 |
| Singh Brothers Construction & Developments Ltd | Construction | 2026 |
| Single File Ltd | Administrative & support | 2012 |
| Singlehurst Consulting Limited | Professional & scientific | 2003 |
| Sinic Holdings Limited | Financial services | 2025 |
| SIT2SLEEP Ltd | Wholesale & retail | 2026 |
| Sivas Property Limited | Real estate | 2020 |
| SIX String Fingerpicking Limited | Education | 2021 |
| SJ Access Solutions Ltd | Construction | 2024 |
| SJ Construction & & Environmental Limited | Construction | 2025 |
| Sjani Limited | Construction | 2020 |
| SJB Assessments Ltd | Administrative & support | 2011 |
| SJC Dance & Performing Arts Ltd | Arts & recreation | 2025 |
| SJC Projects Ltd | Professional & scientific | 2019 |
| SJM Carpets Limited | Construction | 2023 |
| SJM French Polishers & Specialist Decorating Ltd | Construction | 2021 |
| SJM Holdings London Ltd | Financial services | 2026 |
| SJM Specialist Decorations Ltd | Construction | 2022 |
| SJO Author Ltd | Wholesale & retail | 2025 |
| SJS Quantity Surveying Limited | Professional & scientific | 2025 |
| SK Executive Services Limited | Administrative & support | 2019 |
| SK Top Mobiles Limited | Wholesale & retail | 2019 |
| Skill UP Training Academy Ltd | Education | 2020 |
| Skilton Hire Limited | Administrative & support | 2017 |
| Skilton Skips Ltd | Water & waste | 2014 |
| Skinhub-London Ltd | Other services | 2022 |
| Skipper Holdings Limited | Financial services | 2022 |
| Skipper Properties Limited | Real estate | 2021 |
| SKO Property Investments and Managment Ltd | Real estate | 2024 |
| SKR Homes Ltd | Other services | 2017 |
| Skridge Media Ltd | Professional & scientific | 2024 |
| Sky Dental Clinic Orpington Limited | Health & social care | 2024 |
| Sky Roofing (SE) Ltd | Construction | 2024 |
| Skyblue Contracting (UK) Ltd | Construction | 2014 |
| Skycity Properties Ltd | Real estate | 2015 |
| Skye Accounting Limited | Professional & scientific | 2017 |
| Skylark Regeneration Ltd | Professional & scientific | 2026 |
| Skyline Facade and Cladding Ltd | Construction | 2022 |
| Skyline VFX Ltd | Arts & recreation | 2021 |
| Skylon Holdings Limited | Financial services | 2026 |
| Skyward Solutions Limited | Information & communication | 2007 |
| Slavic Clean Ltd | Administrative & support | 2026 |
| SLE M&E Ltd | Professional & scientific | 2021 |
| Slgm Properties Ltd | Real estate | 2015 |
| Slgr Limited | Administrative & support | 2020 |
| Slick Taxis Ltd | Transport & logistics | 2019 |
| Slobod Group Ltd | Construction | 2020 |
| Slopesmj Limited | Households | 2021 |
| Small Steps Together Ltd | Education | 2021 |
| Smart Car & Van Hire Limited | Administrative & support | 2007 |
| Smart DRY Cleaning Ltd | Other services | 2022 |
| Smart Drywall Limited | Construction | 2025 |
| Smart Gift Solutions Limited | Arts & recreation | 2014 |
| Smart Ironing & DRY Cleaning Limited | Other services | 2013 |
| Smart Plumbing Services Ltd | Construction | 2017 |
| Smart Repair Insurance Services Limited | Wholesale & retail | 2009 |
| Smarter Therapy Ltd | Health & social care | 2021 |