| Sienna Tanning and Beauty Studio Ltd | Other services | 2019 |
| Sievingnectar Limited | Information & communication | 2007 |
| Sigma Asset Management Solutions Ltd | Administrative & support | 2022 |
| Signature Bathrooms Wirral Ltd | Administrative & support | 2011 |
| Signature Event Structure Specialists Ltd | Construction | 2018 |
| Signature Holdings (Wirral) Ltd | Other services | 2022 |
| Signature SEW Ltd | Manufacturing | 2024 |
| Significant Interpreting Limited | Administrative & support | 2012 |
| Sigona Engineering Solutions Ltd | Information & communication | 2024 |
| Sihallsailing Ltd | Education | 2023 |
| Silburn-Wilder Group Ltd | Professional & scientific | 2025 |
| Silver Barrel Ltd | Hospitality | 2025 |
| Silver Fern Design Ltd. | Real estate | 1994 |
| Silver Forge Living Ltd | Hospitality | 2024 |
| Simex Systems Limited | Professional & scientific | 2004 |
| Simi Soft Ltd | Information & communication | 2022 |
| Simna Ltd | Information & communication | 2025 |
| Simon Barnes Properties Limited | Real estate | 2005 |
| Simon Kershaw & Associates Limited | Financial services | 2002 |
| Simon Parkes Ltd | Professional & scientific | 2018 |
| Simple Productions Limited | Arts & recreation | 1994 |
| Simple Property Management Ltd | Real estate | 2023 |
| Simplified.Id Ltd | Information & communication | 2008 |
| Simply Better Safety Ltd | Professional & scientific | 2017 |
| Simply Claim Ltd | Professional & scientific | 2024 |
| Simply Skin Store Ltd | Wholesale & retail | 2024 |
| Simply Sunshine Ltd | Manufacturing | 2024 |
| Simplyzenith Ltd | Wholesale & retail | 2017 |
| Sinclair (Wirral) Ltd | Administrative & support | 2011 |
| Sine Wave Media Ltd. | Information & communication | 2017 |
| Sinfom Ltd | Information & communication | 2008 |
| Singsongs Music Limited | Information & communication | 2005 |
| Singularity Software Ltd | Information & communication | 2025 |
| SIR James Properties Ltd | Administrative & support | 2014 |
| Siren Property Developments Ltd | Construction | 2021 |
| Sirius Integrated Building Services Ltd | Professional & scientific | 2020 |
| Sirius Medical Ltd | Health & social care | 2023 |
| Site Skills Knowhow Ltd | Administrative & support | 2019 |
| Site Specific Testing Limited | Professional & scientific | 2018 |
| Site Support Services (North West) Limited | Administrative & support | 2004 |
| Sivamal Limited | Wholesale & retail | 2026 |
| Sivaram Ltd | Wholesale & retail | 2018 |
| Sixwood Limited | Administrative & support | 2005 |
| SJ Body Contour Ltd | Other services | 2024 |
| SJ Finance Services Ltd | Professional & scientific | 2020 |
| SJB Catering Services Limited | Hospitality | 2017 |
| SJB Classic Cars Limited | Wholesale & retail | 2018 |
| SJB Memorials and Grave Care Limited | Other services | 2021 |
| SJD Distribution Ltd | Wholesale & retail | 2025 |
| SJF Property Consultancy Ltd | Professional & scientific | 2025 |
| SJL Electrical Wirral Limited | Construction | 2021 |
| SJM (NW) Property Ltd | Real estate | 2026 |
| SJM 2050 Limited | Administrative & support | 2021 |
| SJP TSA Ltd. | Education | 2014 |
| SJS Care & Support Services Ltd | Health & social care | 2024 |
| SJV Fractional Services Ltd | Professional & scientific | 2025 |
| Skbpm Ltd | Construction | 2023 |
| Skg-Ic Ltd | Professional & scientific | 2020 |
| Skillsbase Northwest Ltd | Education | 2016 |
| Skillsgen Limited | Information & communication | 2000 |
| Skin & Beauty HQ Ltd | Other services | 2024 |
| Skin LDN Ltd | Wholesale & retail | 2016 |
| Skip IT 4 U Limited | Professional & scientific | 2016 |
| Skipso Ltd | Information & communication | 2008 |
| SKN LAB HQ Ltd | Other services | 2026 |
| SKP Advisory Services Ltd | Professional & scientific | 2021 |
| Sky Saving Deals Limited | Wholesale & retail | 2025 |
| Skyhire Access Solutions Limited | Administrative & support | 2012 |
| Skylava Properties Ltd | Real estate | 2026 |
| Skyline Joinery & Install Ltd | Construction | 2023 |
| Skyline Property Letting Limited | Real estate | 2025 |
| Skymentor Limited | Professional & scientific | 2026 |
| SL Lettings Limited | Real estate | 2026 |
| SL Logistic Services Limited | Professional & scientific | 2025 |
| Slab City Comics Limited | Wholesale & retail | 2016 |
| Slack Business Management & Taxes Ltd | Information & communication | 2025 |
| Slater & Green Limited | Education | 2024 |
| Slater Marine Limited | Transport & logistics | 2012 |
| SLB Edwards Ltd | Professional & scientific | 2016 |
| SLC Administrative Services Ltd | Administrative & support | 2025 |
| SLD Legal Consultancy Ltd | Professional & scientific | 2026 |
| Sleepy Sloth Ltd | Wholesale & retail | 2025 |
| Slipstream Leisure Services Ltd | Manufacturing | 2025 |
| SLW Property Holdings Limited | Real estate | 2022 |
| SM & JR Developments Ltd | Real estate | 2026 |
| SM Adhd Consultancy Ltd | Health & social care | 2022 |
| SM Balti House Ltd | Hospitality | 2023 |
| SM Civils & Consultancy Ltd | Construction | 2025 |
| SM Digital Consultancy Limited | Information & communication | 2019 |
| SM Wizard Wash Ltd | Administrative & support | 2022 |
| Small Claims Services Limited | Professional & scientific | 2016 |
| Small Steps Early Years Ltd | Education | 2015 |
| Smart Advantage Ltd | Information & communication | 2021 |
| Smart Distribution Solutions Limited | Other services | 2012 |
| Smart Financial Products Limited | Financial services | 2016 |
| Smart Heating and Home Ltd | Construction | 2021 |
| Smart Home Advice Ltd | Information & communication | 2021 |
| Smart Independent Financial Advice Ltd | Financial services | 2021 |
| Smart Later Life Ltd | Administrative & support | 2023 |
| Smart Living North West Ltd | Real estate | 2024 |