| Scarlex Couriers Ltd | Transport & logistics | 2013 |
| Sces Property Ltd | Real estate | 2017 |
| Scientific Management International Group Limited | Professional & scientific | 2015 |
| Scientific Management International Limited | Manufacturing | 1992 |
| Scotty's Tooling Limited | Manufacturing | 2002 |
| Scratch Print Products Ltd | Manufacturing | 2014 |
| Scruse Holdings Ltd | Construction | 2026 |
| SE Properties and Management Group Limited | Real estate | 2023 |
| Sea Bridge Pro Ltd | Hospitality | 2025 |
| Sea Trade Group Ltd | Wholesale & retail | 2019 |
| Seabag Limited | Real estate | 1968 |
| Seabird Packaging Limited | Manufacturing | 2006 |
| Seafarers Management Solutions Ltd | Professional & scientific | 2022 |
| Seahorse Innovations Limited | Professional & scientific | 2016 |
| Sealock Limited | Manufacturing | 1983 |
| Seasons Enterprise Limited | Arts & recreation | 2025 |
| Second Half Ventures Ltd | Wholesale & retail | 2026 |
| Secura Monde International Limited | Manufacturing | 1996 |
| Secure Environments Limited | Administrative & support | 2015 |
| Secure Safe Storage - Andover Ltd | Transport & logistics | 2025 |
| Secureack Limited | Information & communication | 2022 |
| Secureshift Ltd | Information & communication | 2023 |
| Seeed Limited | Construction | 2003 |
| Seek Kaizen Ltd | Wholesale & retail | 2024 |
| Seeskisurf Ltd | Hospitality | 2022 |
| Segal & Co Ltd | Professional & scientific | 2012 |
| Selavee Escapes Ltd | Real estate | 2026 |
| Select Aerospace Technologies Limited | Wholesale & retail | 2003 |
| Self Hire FLY Ltd | Arts & recreation | 2019 |
| Senddoor Express Ltd | Wholesale & retail | 2025 |
| Senedy Averr Ltd | Wholesale & retail | 2025 |
| Senjo Construction Services Limited | Manufacturing | 2020 |
| Senjo Limited | Real estate | 2001 |
| Sentinelnet Ltd | Information & communication | 2025 |
| Sequoia Trading Ltd | Professional & scientific | 2010 |
| Serenity Expert Social Work Ltd | Health & social care | 2007 |
| Serenity Hair TLC Limited | Other services | 2017 |
| Serviss Pluss Ltd | Transport & logistics | 2021 |
| Sesanti Limited | Manufacturing | 2013 |
| Sets Andover Limited | Wholesale & retail | 2024 |
| Sets Garages Limited | Wholesale & retail | 2025 |
| Seymour Builders Limited | Construction | 1997 |
| Sgrw Limited | Professional & scientific | 2008 |
| SGW Property Developments Ltd | Construction | 2026 |
| SH & GS Property Group Limited | Real estate | 2017 |
| Shaan Business Services Limited | Administrative & support | 2022 |
| Shade Hairdressing Ltd | Other services | 2018 |
| Shahi RAJ Cuisine Ltd | Hospitality | 2021 |
| Shahin Catering Limited | Hospitality | 2019 |
| Shakespeare Builders ( Andover) Ltd | Construction | 2018 |
| Sharda Business Solutions Limited | Administrative & support | 2025 |
| Sharehoperr Ltd | Hospitality | 2025 |
| Sharper Haven & Co Limited | Manufacturing | 2025 |
| Shearmans Limited | Wholesale & retail | 2002 |
| Shelton & White Limited | Information & communication | 2017 |
| Shenton Global Limited | Professional & scientific | 2016 |
| Shenton Group Holdings Limited | Financial services | 2025 |
| Shergold Cyber Security Services Ltd | Information & communication | 2025 |
| Shineehav Ltd | Wholesale & retail | 2025 |
| Shining Hill Healthcare Limited | Health & social care | 2024 |
| Shiretoko Ltd | Financial services | 2017 |
| Shiva Yoga Ltd | Health & social care | 2025 |
| Shoes on Theatre Limited | Arts & recreation | 2018 |
| Shoreline Steel Structures Limited | Construction | 2020 |
| Sibley's Ltd | Wholesale & retail | 2024 |
| Sids Care Services Limited | Health & social care | 2022 |
| Sigma Beta CAD Ltd | Construction | 2020 |
| Signs of Change Ltd | Professional & scientific | 2020 |
| Sigvaris Britain Limited | Health & social care | 1992 |
| Silva Neves Consultancy Ltd | Professional & scientific | 2019 |
| Silva Neves Psychotherapy Limited | Health & social care | 2021 |
| Silver Badger Limited | Information & communication | 2020 |
| Silverwood Assets Limited | Administrative & support | 2017 |
| Silviutop Trans Ltd | Transport & logistics | 2017 |
| Simple Office Solutions Limited | Manufacturing | 2001 |
| Simple Snaps Ltd | Professional & scientific | 2021 |
| Simplex-Turbulo Company Limited | Transport & logistics | 1980 |
| Simply Essential Goods UK Ltd | Wholesale & retail | 2025 |
| Simplyhealth Access | Health & social care | 1922 |
| Simplyhealth Foundry Limited | Financial services | 2022 |
| Simplyhealth Funding Services Limited | Financial services | 1998 |
| Simplyhealth Group Limited | Health & social care | 2005 |
| Simplyhealth Guidance Limited | Health & social care | 2016 |
| Simplyhealth Holdings Limited | Health & social care | 2005 |
| Simplyhealth Nominees Limited | Financial services | 2005 |
| Simplyhealth People Limited | Health & social care | 2005 |
| Simplyhealth Venture Capital Limited | Financial services | 2022 |
| Simplyhealth Venture One Limited | Health & social care | 2023 |
| Simplyhealth Venture Two Limited | Information & communication | 2026 |
| Sinclair Youngs Rentals Limited | Administrative & support | 1995 |
| Sion Scent Limited | Manufacturing | 2023 |
| Sisterson Limited | Other services | 2023 |
| SJ Realty Limited | Real estate | 2020 |
| Sjam Systems Consulting Ltd | Professional & scientific | 2021 |
| SJB Scientific Limited | Professional & scientific | 2026 |
| Sjbb Limited | Information & communication | 2016 |
| SJC Designs Online Ltd | Professional & scientific | 2017 |
| SJK Media Ltd | Information & communication | 2010 |
| SK Pet Travel Experts Limited | Professional & scientific | 2023 |
| Skillfill Ltd | Administrative & support | 2025 |