| Southbeach Management Limited | Households | 2012 |
| Southcourt Developments Limited | Construction | 2004 |
| Southcroft Farm Residents Management Company Limited | Households | 2025 |
| Southdown PSV Limited | Transport & logistics | 2002 |
| Southern Powergrid Limited | Extraterritorial | 2011 |
| Southern Railway Limited | Transport & logistics | 2008 |
| Southern Vectis Limited | Professional & scientific | 1986 |
| Southern Vectis Omnibus Company Limited(The) | Professional & scientific | 1929 |
| Southview Leisure Park Limited | Hospitality | 2006 |
| Southwick Development Ltd | Construction | 2022 |
| Southwood Enterprises Ltd | Other services | 2022 |
| Sovereign Compliance Ltd | Professional & scientific | 2011 |
| Sovereign Distribution Ltd | Transport & logistics | 2018 |
| SOW Grow and Cook CIC | Health & social care | 2024 |
| Sowmyaa 9 PVT Ltd | Wholesale & retail | 2026 |
| SOZ Ltd | Real estate | 2024 |
| SP Builders Ltd | Construction | 2025 |
| Spa Live Ltd | Administrative & support | 2025 |
| Spa TM Ltd | Construction | 2019 |
| Space (Newcastle) Limited | Health & social care | 2025 |
| Space Architects (Europe) Limited | Information & communication | 2019 |
| Space Haven Property Management Ltd | Real estate | 2026 |
| Space Inside Ltd | Professional & scientific | 2019 |
| Space Intelligence AI Ltd | Information & communication | 2026 |
| Space to Build Ltd | Professional & scientific | 2020 |
| Space to Operate Ltd | Hospitality | 2020 |
| Spacex Digital Limited | Wholesale & retail | 2025 |
| Spahire.Com Limited | Administrative & support | 2021 |
| Span Property Ltd | Real estate | 2024 |
| Spanner Monkeys NE Limited | Wholesale & retail | 2015 |
| Spark Contracts Ltd | Administrative & support | 2014 |
| Spark Evolution Ltd | Information & communication | 2025 |
| Spark Innovation Northeast Limited | Other services | 2021 |
| Spark Services Limited | Wholesale & retail | 2025 |
| Sparkling Nails 98 Ltd | Other services | 2025 |
| Sparkling Stars Community Interest Company | Education | 2023 |
| Sparkplus Services Ltd | Administrative & support | 2014 |
| Spartan Maintenance Limited | Construction | 2025 |
| Spatial Geomatics Ltd | Professional & scientific | 2007 |
| Spaza Deli Ltd | Manufacturing | 2025 |
| Spazio Bianco Ltd | Professional & scientific | 2018 |
| Spcc Global Limited | Administrative & support | 2025 |
| SPD7 Resources Limited | Construction | 2020 |
| Speak Inspire Lead Limited | Professional & scientific | 2019 |
| Speakers of Life Community Interest Company | Health & social care | 2019 |
| Spearhead Interactive Limited | Information & communication | 2013 |
| Specialised Contracting Services Limited | Construction | 1983 |
| Specialist Alarm Services Limited | Manufacturing | 1981 |
| Specialist Asbestos Services Limited | Professional & scientific | 2016 |
| Specialist Ceilings & Partitions Limited | Construction | 2025 |
| Specialist Panels UK Limited | Manufacturing | 2009 |
| Specialist Umbilical Services Ltd | Professional & scientific | 2005 |
| Specials Wholesale Limited | Wholesale & retail | 2018 |
| Specs 4 YOU Ltd | Wholesale & retail | 2019 |
| Spectateher Limited | Information & communication | 2024 |
| Spectra Perfumes Ltd | Wholesale & retail | 2025 |
| Spectra Sales Solutions Limited | Professional & scientific | 2012 |
| Spectrum 2000 Limited | Construction | 1999 |
| Spectrum-Link Limited | Information & communication | 2026 |
| Spedding Property Holdings Limited | Real estate | 2019 |
| Speech Sparks Ltd | Health & social care | 2024 |
| Speed Healthcare Ltd | Public administration | 2025 |
| Speedflex (UK & Ireland) Limited | Arts & recreation | 2010 |
| Speedlab Group Limited | Wholesale & retail | 2022 |
| Speedsale Limited | Wholesale & retail | 2006 |
| Speedy Pizza Lemington Ltd | Hospitality | 2019 |
| Spence & Dower LLP | | 2010 |
| Spence Terrace Investments Limited | Hospitality | 2002 |
| Spencer Cars Limited | Transport & logistics | 2012 |
| Spencer Francis Limited | Construction | 1995 |
| Spencer James Properties Limited | Real estate | 2020 |
| Sperans Limited | Financial services | 2024 |
| Speur Films Limited | Administrative & support | 2012 |
| SPF Design Solutions Limited | Professional & scientific | 2013 |
| Sphere Safety & Health Ltd | Education | 2020 |
| Spherical Developments Limited | Hospitality | 2019 |
| Sphion Ltd | Professional & scientific | 2018 |
| Spice Beez Ltd | Hospitality | 2018 |
| Spice Fossway Tandoori Ltd | Hospitality | 2021 |
| Spice Garden (Ocean Road) Ltd | Hospitality | 2019 |
| Spice of Punjab Ltd | Hospitality | 2023 |
| Spice Project Limited | Information & communication | 2007 |
| Spice UP Grill Ltd | Hospitality | 2022 |
| Spice UP Mandi House Ltd | Hospitality | 2025 |
| Spice Valley Allendale Ltd | Hospitality | 2024 |
| Spice&Treatz Limited | Wholesale & retail | 2025 |
| Spicy HUT Newcastle Ltd | Hospitality | 2025 |
| Spicy Solutions Newcastle Ltd | Hospitality | 2021 |
| Spiffing Chaps Limited | Information & communication | 2013 |
| Spike (NCL) Limited | Transport & logistics | 2024 |
| Spillcentre Ltd | Wholesale & retail | 2018 |
| Spinback Furniture Ltd | Manufacturing | 2023 |
| Spinflow Ltd | Manufacturing | 2023 |
| Spinnaka Limited | Professional & scientific | 2002 |
| Spiral 4 Limited | Administrative & support | 2003 |
| Spirit Advisory Ltd | Professional & scientific | 2021 |
| Spirit and Spritz Limited | Manufacturing | 2025 |
| Spirit Ford Limited | Wholesale & retail | 2023 |
| Spiriti Ltd | Professional & scientific | 2008 |
| Spjj Traffic Management Ltd | Construction | 2024 |