| Sparkage Limited | Households | 1987 |
| Spartan UK Limited | Manufacturing | 2001 |
| Special Occasions North East Ltd | Wholesale & retail | 2016 |
| Specialised Access Systems Ltd | Construction | 2019 |
| Specialist Building Elites Limited | Construction | 2017 |
| Specialist Logistics Solutions (SLS) Limited | Transport & logistics | 2010 |
| Spectre Publishing Ltd | Information & communication | 2021 |
| Spectrum FM Certificates Ltd | Other services | 2025 |
| Spectrum FM M&E Ltd | Construction | 2025 |
| Spectrum FM New & Maintain Ltd | Construction | 2025 |
| Spectrum Interiors (North East) Ltd | Construction | 2008 |
| Spectrum Paint (NE) Ltd | Construction | 2025 |
| Speed Office Supplies Limited | Wholesale & retail | 2004 |
| Spelk Collective Ltd | Wholesale & retail | 2025 |
| Spelk Limited | Manufacturing | 2025 |
| Spencers Estates Ltd | Extraterritorial | 2011 |
| Spencerscom Limited | Real estate | 2008 |
| Spend & Save a Ltd | Wholesale & retail | 2021 |
| Sphera Consulting Ltd | Professional & scientific | 2011 |
| Spice Connection Gateshead Ltd | Hospitality | 2021 |
| Spicenslice NE Ltd | Hospitality | 2025 |
| Spicker & Steen Ltd | Wholesale & retail | 2004 |
| Spilt Milk Band Limited | Arts & recreation | 2025 |
| Spine Cure & Care Limited | Extraterritorial | 2017 |
| Spine Solutions Limited | Health & social care | 2011 |
| Spinning Yarns Productions Limited | Financial services | 2025 |
| Spitz Ltd | Administrative & support | 2021 |
| Splashworks Designer Bathrooms Ltd | Construction | 2023 |
| Splashworks Trade Limited | Construction | 2024 |
| Split Bean Coffee Company Limited | Hospitality | 2014 |
| Spmh Services Ltd | Professional & scientific | 2022 |
| Sporting Journeys NE Ltd | Other services | 2022 |
| Sportmemorabiliauk Ltd | Manufacturing | 2026 |
| Sports & Management NE Ltd | Professional & scientific | 2024 |
| Sportsking Coaching NE Limited | Education | 2023 |
| Spotless Interactive Limited | Information & communication | 2004 |
| Sppne Ltd | Construction | 2024 |
| Spratt's Stores Limited | Real estate | 1938 |
| Spraycrete Tunnelling Limited | Construction | 2020 |
| Springview Property Limited | Real estate | 2025 |
| Springwell Roofing Limited | Construction | 2004 |
| Sprouting Languages Limited | Education | 2025 |
| Spud Stop (NE) Limited | Hospitality | 2025 |
| SPY Monkey (NE) Limited | Arts & recreation | 2012 |
| SR Properties Hartlepool Ltd | Real estate | 2020 |
| SR Shopfitters Ltd | Construction | 2016 |
| SRB Real Estate Ltd | Real estate | 2020 |
| SRE Serene Group Ltd | Real estate | 2025 |
| SRF Security Ltd | Construction | 2023 |
| SRI Projects (NE) Limited | Real estate | 2013 |
| SRI Raghava Limited | Hospitality | 2024 |
| SRL Projects Ltd | Information & communication | 2022 |
| SRL Solutions Limited | Construction | 2012 |
| SRS Private Limited | Wholesale & retail | 2017 |
| SS Home Solutions (NE) Limited | Health & social care | 2026 |
| Ssleep Limited | Wholesale & retail | 2024 |
| Sstc Enterprise Limited | Administrative & support | 2023 |
| ST Andrews Church Ltd | Real estate | 2020 |
| ST Chad's Community Project | Health & social care | 2001 |
| ST Cuthbert's House Limited | Health & social care | 2007 |
| ST George Property Estates Ltd | Construction | 2021 |
| ST James NV 911 Limited | Real estate | 2016 |
| ST James NV Limited | Real estate | 2015 |
| ST James Parking Ltd | Transport & logistics | 2024 |
| ST Laurence Properties Limited | Real estate | 2013 |
| ST Sushi Limited | Hospitality | 2014 |
| ST Vehicle Movement Ltd | Transport & logistics | 2023 |
| ST. Philip's Pre-School | Education | 2008 |
| St.Alphonsa DGP Limited | Wholesale & retail | 2025 |
| Stacey Jane Beauty Ltd | Other services | 2026 |
| Stackpole Investments Limited | Professional & scientific | 2006 |
| Stadium and Event Solutions Limited | Professional & scientific | 2015 |
| Standard Aviation Limited | Professional & scientific | 1982 |
| Stanhope Apartments Ltd | Real estate | 2018 |
| Stanleys Medical Limited | Health & social care | 2011 |
| Stannington Properties LLP | | 2015 |
| Stanton Croft Limited | Professional & scientific | 2004 |
| Staplehurst Bayis Investments Ltd | Real estate | 2024 |
| Staplehurst Commercial Limited | Real estate | 2025 |
| Star Martins Ltd | Hospitality | 2019 |
| Star Properties (Newcastle) Limited | Other services | 2001 |
| Star-Rent Ltd | Real estate | 2024 |
| Stardust Service (Southwest) Ltd | Administrative & support | 2021 |
| Stargaze Properties NE Limited | Real estate | 2025 |
| Starstream Data Ltd | Information & communication | 2008 |
| Startribes Ltd | Professional & scientific | 2020 |
| Stator Made Limited | Other services | 2012 |
| Stator Studios Ltd | Information & communication | 2024 |
| Statrad Ltd | Real estate | 2020 |
| Steld Developments Limited | Construction | 2024 |
| Steld Limited | Real estate | 2021 |
| Stenhouse Shop Ltd | Wholesale & retail | 2026 |
| Step UP Scaffolding (UK) Limited | Wholesale & retail | 2016 |
| Stephanie Durham Limited | Health & social care | 2013 |
| Stephen Blaylock Ltd | Construction | 2018 |
| Stepup Octo UK Limited | Wholesale & retail | 2020 |
| Steve's Courier Services Limited | Transport & logistics | 2021 |
| Steven Gibbons Consulting Limited | Information & communication | 2026 |
| Stick Theory Limited | Professional & scientific | 2009 |
| Stirling Performance Solutions Limited | Professional & scientific | 2023 |