| ST James Secretaries Limited | Professional & scientific | 1998 |
| ST Johns Village Lettings Limited | Real estate | 2025 |
| ST Johns Village Rentals Limited | Professional & scientific | 2026 |
| ST Marks Management Limited | Households | 1998 |
| ST Mary's Cash & Carry Ltd | Wholesale & retail | 2024 |
| ST Mary's Football Group Limited | Professional & scientific | 2009 |
| ST Mary's Independent School Ltd. | Education | 2013 |
| ST Mary's Training Ground Limited | Real estate | 2009 |
| ST Marys Catering Limited | Professional & scientific | 2010 |
| ST Marys Lettings Ltd | Real estate | 2024 |
| ST Marys SPV Limited | Professional & scientific | 2000 |
| ST Marys Stadium Limited | Extraterritorial | 1999 |
| ST Michael Medical Services Ltd | Health & social care | 2025 |
| ST Michael's Hall Property Management Limited | Real estate | 1996 |
| ST Michaels Street Southampton Limited | Households | 2016 |
| ST Monica Takeaway Ltd | Hospitality | 2019 |
| ST MONICA88 Limited | Hospitality | 2026 |
| ST Pauls Court (Winchester) Limited | Households | 1987 |
| ST Peters House Bishops Waltham Limited | Households | 1994 |
| ST Peters Property Management Limited | Administrative & support | 2004 |
| ST Prime Digital Ltd | Wholesale & retail | 2025 |
| ST Woodrow Care 1 Ltd | Health & social care | 2019 |
| ST. Agatha's Trust | Arts & recreation | 1987 |
| ST. Andrew's Coffee House Limited | Hospitality | 2017 |
| ST. Ann's Court Residents Management Company Limited | Households | 2003 |
| ST. George's Educational Services Ltd | Education | 2023 |
| ST. Georges (Bursledon) Management Company Limited | Households | 1981 |
| ST. Johns (Hedge END) Residents Limited | Households | 2016 |
| ST. Mary's Training Centre Limited | Professional & scientific | 1994 |
| ST. Paul's Place (Property) Limited | Households | 2010 |
| ST. Paul's Place (Winchester) Limited | Households | 1987 |
| ST. Peter Street Management Company Limited | Households | 2013 |
| ST. Peters Construction Limited | Extraterritorial | 2008 |
| St.Cyms Ltd | Transport & logistics | 2021 |
| STA Security and Facility Management Limited | Administrative & support | 2024 |
| Staars LLP | | 2002 |
| Stable Productions Limited | Information & communication | 2022 |
| Stable Rock Limited | Wholesale & retail | 2016 |
| Stablescale Ltd | Professional & scientific | 2025 |
| Stableyard Investments Limited | Financial services | 2018 |
| Stackd Gym Wear Ltd | Wholesale & retail | 2023 |
| Stackregime Ltd | Information & communication | 2026 |
| Staff International Limited | Other services | 2023 |
| Staff.Zone Limited | Administrative & support | 2018 |
| Staffing Solutions Healthcare Specialist Ltd | Administrative & support | 2022 |
| Stafford House Developments Limited | Construction | 1989 |
| Stafford House Limited | Real estate | 2022 |
| Stafford Property Portfolio Ltd | Real estate | 2026 |
| Stag & Spaniel Estates Limited | Real estate | 2025 |
| Stag Carpentry and Contractors Ltd | Construction | 2025 |
| Stag Gate Mews RTM Company Ltd | Households | 2014 |
| Stag Gates Properties Limited | Real estate | 2008 |
| Stag Homes Limited | Real estate | 2014 |
| Stag Mews Management Company Limited | Households | 2012 |
| Stag Properties Southern Ltd | Real estate | 2025 |
| Stage 4 Limited | Hospitality | 2007 |
| Stage BLU Limited | Hospitality | 2021 |
| Stage Seven Limited | Hospitality | 2020 |
| Staggered Trading Limited | Manufacturing | 2007 |
| Stags in the Community C.I.C. | Other services | 2017 |
| Stainton Prop Co Ltd | Real estate | 2026 |
| Stakks Pancake House Limited | Hospitality | 2015 |
| Stakks@Chandlers Ford Ltd | Hospitality | 2018 |
| Stalbridge Park Homes Limited | Construction | 2020 |
| Stalev Construction Ltd | Construction | 2024 |
| Stalla Limited | Hospitality | 2022 |
| Staltosi Financial Planning Limited | Financial services | 2026 |
| Staltosi Property Limited | Real estate | 2018 |
| Stalwart Consults International Ltd | Information & communication | 2026 |
| Stam Limited | Professional & scientific | 2025 |
| Stampout Ltd | Administrative & support | 2024 |
| Stanbridge Family Office Ltd | Financial services | 2018 |
| Stanbridge Group Limited | Professional & scientific | 1991 |
| Stanbridge Wealth Limited | Financial services | 2019 |
| Stand OUT Spaces Ltd | Real estate | 2025 |
| Standard Trading and Logistic LLP | | 2012 |
| Standards Care Limited | Administrative & support | 2017 |
| Standu Ltd | Transport & logistics | 2019 |
| Stanelco RF Technologies Limited | Manufacturing | 1997 |
| Stanikzai Ltd | Wholesale & retail | 2023 |
| Stanil UK Ltd | Financial services | 2025 |
| Stanislas Media Limited | Information & communication | 2018 |
| Stanley Diorite Ltd. | Manufacturing | 2013 |
| Stanmore Hampshire Limited | Real estate | 2020 |
| Stanwell Rest Home Limited | Health & social care | 1995 |
| Stapleford Horses Ltd | Agriculture & fishing | 2024 |
| Staplewood Construction Limited | Construction | 2019 |
| Star Accounts (UK) Limited | Information & communication | 2013 |
| Star Advanced Beauty Ltd | Other services | 2014 |
| Star and Moon Healthcare Services Ltd | Transport & logistics | 2022 |
| Star General Ltd | Wholesale & retail | 2020 |
| Star Grill and Pizza Ltd | Hospitality | 2025 |
| Star Kebab & Grilled Food Ltd | Hospitality | 2020 |
| Star Oriental Trading Ltd | Wholesale & retail | 2021 |
| Star Serpent Records Ltd | Information & communication | 2020 |
| Star Sports and Fitness Ltd | Wholesale & retail | 2015 |
| Star Trending Goods Limited | Wholesale & retail | 2023 |
| Star-Delta Electrical Services Limited | Construction | 2015 |
| Starboard Accountants Limited | Professional & scientific | 2022 |
| Starboard Stays Southampton Limited | Hospitality | 2022 |