| SNW Consulting MK Limited | Real estate | 2020 |
| SO Clean Services Ltd | Administrative & support | 2025 |
| SO Prem Ltd | Administrative & support | 2024 |
| SO Solid Construction Limited | Construction | 2024 |
| Soamazing Ltd | Health & social care | 2024 |
| Soaring Seasons Limited Limited | Real estate | 2023 |
| Soaring Wings Care Services Ltd | Health & social care | 2025 |
| Sobre MI C.I.C. | Administrative & support | 2025 |
| Socforge Consulting Ltd | Professional & scientific | 2026 |
| Sochev Food and Services Ltd | Wholesale & retail | 2025 |
| Social Justice International CIC | Professional & scientific | 2015 |
| Social P.A. Ltd | Administrative & support | 2022 |
| Social Pioneers Limited | Professional & scientific | 2009 |
| Social Steering Limited | Information & communication | 2019 |
| Socius Investing Limited | Professional & scientific | 2015 |
| Sodiaal UK Limited | Wholesale & retail | 1977 |
| Soekm Limited | Information & communication | 2016 |
| Sofa Lounge Limited | Wholesale & retail | 2013 |
| Sofetech Safety Connects UK Limited | Professional & scientific | 2026 |
| Sofine Furniture Ltd | Wholesale & retail | 2025 |
| Softamber Limited | Information & communication | 2020 |
| Softek Healthcare Solutions Limited | Information & communication | 2007 |
| Softlife Holdings Limited | Professional & scientific | 2015 |
| Softpawa Limited | Information & communication | 2017 |
| Softsyncai Limited | Information & communication | 2026 |
| Softxnet Consulting Ltd | Information & communication | 2013 |
| Soglaze Protection and Indemnity Company Limited | Financial services | 2026 |
| Sohobasement Limited | Information & communication | 2016 |
| SOK Group Ltd | Wholesale & retail | 2024 |
| Soki 80 Ltd | Other services | 2019 |
| Sokoke Ltd | Wholesale & retail | 2021 |
| SOL Eco Services Limited | Construction | 2009 |
| Sola Diagnostics UK Ltd | Professional & scientific | 2024 |
| Solace Care Support Services Ltd | Health & social care | 2026 |
| Solace Consult Limited | Administrative & support | 2017 |
| Solair Services Limited | Transport & logistics | 2024 |
| Solanes Limited | Manufacturing | 2018 |
| Solange Diamant Ltd | Professional & scientific | 2011 |
| Solanki Associates Limited | Professional & scientific | 2010 |
| Solar FM Services Ltd | Construction | 2023 |
| Solar Partner Limited | Construction | 2016 |
| Solari Living Ltd | Real estate | 2022 |
| Solariis Group Ltd | Wholesale & retail | 2025 |
| Solaris Horizon Energy Ltd | Construction | 2025 |
| Solarisk Consulting Ltd | Professional & scientific | 2024 |
| Sole BIZ Limited | Wholesale & retail | 2023 |
| Sole Enterprisis Limited | Health & social care | 2023 |
| Soli Consulting Ltd | Professional & scientific | 2023 |
| Solid Accounts Ltd | Professional & scientific | 2021 |
| Solid Mirror Properties Limited | Real estate | 2023 |
| Solid Stone Paving Limited | Construction | 2018 |
| Solid Systems Info Tech Ltd | Information & communication | 2017 |
| Solidaire Law Limited | Professional & scientific | 2023 |
| Solidoak Property Investments Limited | Real estate | 2026 |
| Solidus Roofing Ltd | Construction | 2026 |
| Solifi Group (UK) Limited | Other services | 1993 |
| Solihull BSF Schools (Holdings) Limited | Financial services | 2006 |
| Solihull BSF Schools Limited | Construction | 2006 |
| Solimhealthuk Ltd | Health & social care | 2025 |
| Solis Productions Ltd | Information & communication | 2024 |
| Solix Group Ltd | Professional & scientific | 2026 |
| Solmere Electrical Ltd | Construction | 2020 |
| Solo Connects Limited | Other services | 2025 |
| Solomon Housing Incorporation Private Limited | Construction | 2026 |
| Solomon Incorporation Private Limited | Information & communication | 2025 |
| Solore Group Limited | Professional & scientific | 2026 |
| Sols Health UK Ltd | Health & social care | 2020 |
| Solstice Hair Ltd | Other services | 2025 |
| Soltaro Limited | Construction | 2015 |
| Soltaro-Uk Ltd | Construction | 2025 |
| Soltherm External Insulations Ltd | Wholesale & retail | 2016 |
| Solution Nest Ltd | Information & communication | 2025 |
| Solution Properties Limited | Real estate | 2014 |
| Solution to Healthcare Limited | Administrative & support | 2023 |
| Solutions (MK) Ltd | Information & communication | 2025 |
| Solutions Benchmark Systems Ltd | Information & communication | 2026 |
| Solutions Tech Ltd | Wholesale & retail | 2017 |
| Solutions Through Knowledge Contracts Limited | Information & communication | 2003 |
| Solutions-Forge Ltd | Information & communication | 2025 |
| Solvocoat Additives & Chemicals Ltd | Wholesale & retail | 2020 |
| Solvotrin Therapeutics (UK) Limited | Health & social care | 2018 |
| Solvyn Care Ltd | Health & social care | 2026 |
| SOM Coffee MK Ltd | Hospitality | 2024 |
| Somali Diaspora Foundation Ltd | Other services | 2017 |
| Somaplus Limited | Professional & scientific | 2022 |
| Somerset Equipment Finance (UK) Ltd | Administrative & support | 2011 |
| Somerset Schools 1 (Holdings) Limited | Construction | 2010 |
| Somerset Schools 1 Limited | Construction | 2010 |
| Somewhatmedia Limited | Professional & scientific | 2023 |
| Somnium Recruitment Ltd | Administrative & support | 2018 |
| Somsons General Accountancy Ltd | Professional & scientific | 2026 |
| SON of Major Ltd | Manufacturing | 2025 |
| Sonatest Ltd | Manufacturing | 1965 |
| Sonatest NDE Limited | Administrative & support | 1985 |
| Soneira Ltd | Wholesale & retail | 2025 |
| Sonepar UK Limited | Financial services | 2014 |
| Sonesq Ltd | Professional & scientific | 2022 |
| Songbird Creations Limited | Information & communication | 2009 |
| Sonic Bass Limited | Administrative & support | 2015 |
| Sonobelle Medical Ltd | Health & social care | 2026 |