| Seren Project Solutions Ltd | Professional & scientific | 2024 |
| Serena Sartorial Ltd | Manufacturing | 2019 |
| Serenaratna Ltd | Wholesale & retail | 2024 |
| Serendipity Interim Management Ltd. | Professional & scientific | 2014 |
| Serene Residential Ltd. | Real estate | 2025 |
| Serenity Care Agency Ltd | Health & social care | 2021 |
| Serious Software Limited | Information & communication | 2011 |
| Served Technologies Limited | Information & communication | 2023 |
| Service Assured Ltd | Administrative & support | 2018 |
| Service Innovation Group-Uk Limited | Administrative & support | 1979 |
| Service Management Solutions Ltd | Information & communication | 2019 |
| Service Renewals Limited | Wholesale & retail | 2011 |
| Service Wrap IT Limited | Information & communication | 2014 |
| Servicefill Limited | Construction | 2014 |
| SET Medical Ltd | Health & social care | 2020 |
| SET Residential Ltd | Real estate | 2021 |
| Setai Investment Limited | Manufacturing | 2020 |
| Sethi & Madhan Ltd | Manufacturing | 2019 |
| Setl Limited | Information & communication | 2019 |
| Setomctech Ltd | Information & communication | 2017 |
| Setu Holdings Ltd | Financial services | 2025 |
| Setu Investments Ltd | Information & communication | 2025 |
| Seva Developments Group Ltd | Construction | 2026 |
| Sevai Technologies Ltd | Information & communication | 2020 |
| Sevastian Chauffeur Ltd | Transport & logistics | 2026 |
| Seven & I Limited | Wholesale & retail | 2015 |
| Seven & Seven Producer's Sales Service Limited | Information & communication | 2010 |
| Seven ATE Foods Ltd | Manufacturing | 2024 |
| Seven Pines Consulting Ltd | Professional & scientific | 2023 |
| Seven Seeded Limited | Manufacturing | 2006 |
| Seven Star Investment UK Limited | Hospitality | 2026 |
| Sevendec Health Limited | Manufacturing | 2025 |
| SEVENOCEANS2 Properties Limited | Construction | 2025 |
| Seventeen Ferncroft Limited | Real estate | 1988 |
| Seventeen Well Ltd | Health & social care | 2026 |
| Seventhseason Limited | Administrative & support | 2018 |
| SEVENTY8 Clothing Limited | Wholesale & retail | 2016 |
| Sevid Ltd | Construction | 2021 |
| Sevulara Properties Ltd | Real estate | 2019 |
| Sewing Alterations Ltd | Professional & scientific | 2025 |
| Sexton Villas Limited | Households | 2015 |
| Sexy Sumo Ltd | Real estate | 2024 |
| Seymour Court (Eversley Park Road N21) Management Limited | Real estate | 1976 |
| Seymour Court Freeholders Limited | Real estate | 2011 |
| Seymour Road Services Limited | Real estate | 2011 |
| Seyon IT Consulting Ltd | Information & communication | 2017 |
| SF Stefan Civil Ltd | Construction | 2019 |
| SFA Saniflo UK Ltd | Wholesale & retail | 1979 |
| SG Invest Ltd | Financial services | 2024 |
| SG Residential and Commercial Limited | Administrative & support | 2016 |
| SG47 Limited | Real estate | 2025 |
| SGA Learning Ltd | Education | 2018 |
| SGB Associates Limited | Professional & scientific | 2004 |
| Sgconvey Limited | Real estate | 2024 |
| SGD Carpentry&Joinery Ltd | Construction | 2022 |
| SGD Designs Ltd | Manufacturing | 2018 |
| SGK Property-Services Limited | Real estate | 2020 |
| Sglhomes Ltd | Households | 2017 |
| SGN Advisors Limited | Professional & scientific | 2017 |
| SGO Design and Build Ltd | Construction | 2025 |
| SGP International Limited | Real estate | 2018 |
| SGS Consultants Ltd | Administrative & support | 2022 |
| SGS Global Consultancy Ltd | Information & communication | 2018 |
| Sgss Gurdwara Watford CIC | Other services | 2023 |
| SGT Global Limited | Professional & scientific | 2025 |
| SH Consulting Group Limited | Information & communication | 2022 |
| SH Professional Care Ltd | Health & social care | 2022 |
| Sha-Ma Consultancy Ltd | Manufacturing | 2022 |
| Shaafia Ltd | Financial services | 2018 |
| Shaan Xpress Limited | Hospitality | 2025 |
| Shabab Limited | Transport & logistics | 2025 |
| Shabach Limited | Real estate | 2020 |
| Shabbar-Al-Mujtaba Limited | Real estate | 2014 |
| Shabron Investments Limited | Real estate | 2021 |
| Shadfeb Limited | Professional & scientific | 2016 |
| Shah's Properties & Investment Ltd | Real estate | 2021 |
| Shah-Dawes Ltd | Real estate | 2025 |
| Shahashra Entertainments Limited | Arts & recreation | 2023 |
| Shahtaj Ltd | Wholesale & retail | 2025 |
| Shai Consulting Limited | Information & communication | 2024 |
| Shaifta Partners Ltd | Professional & scientific | 2023 |
| Shaitrii Limited | Professional & scientific | 2024 |
| Shakespeare Court Woodville Road Management Co. Limited | Households | 1984 |
| Shala Building Company Ltd | Real estate | 2023 |
| Shalli Price Ltd | Wholesale & retail | 2025 |
| Sham Gate Shipping Services Ltd | Transport & logistics | 2021 |
| Sham Performance Ltd | Wholesale & retail | 2026 |
| Shamrock Accounting, Tax and Payroll Limited | Professional & scientific | 2018 |
| Shamsher Ltd | Health & social care | 2022 |
| Shamsher Real Estate Ltd | Real estate | 2025 |
| Shan Business Partnerships Ltd | Professional & scientific | 2016 |
| Shan CARE24 Ltd | Administrative & support | 2021 |
| Shand Mining Limited | Professional & scientific | 1975 |
| Shandilya Properties Limited | Real estate | 2018 |
| Shaneel Mexico Limited | Wholesale & retail | 2020 |
| Shankwill LP | | 2017 |
| Shanmith Ltd | Wholesale & retail | 2015 |
| Shannon Integrated Services Limited | Construction | 2008 |
| Shannon Medical & Training Limited | Other services | 2010 |
| Shannon Rail Limited | Transport & logistics | 2006 |