| SH Drinks Limited | Hospitality | 2019 |
| SH Prime Properties Limited | Real estate | 2023 |
| SH Properties Management Ltd | Real estate | 2012 |
| SHA Impex Limited | Wholesale & retail | 2019 |
| Shah Repairs Ltd | Wholesale & retail | 2013 |
| Sharevalue Limited | Financial services | 1988 |
| Sharp Cleaning Services NE Ltd | Administrative & support | 2023 |
| Sharp Hedges Tree & Garden Services Ltd | Administrative & support | 2026 |
| Sharp Snip Limited | Manufacturing | 2025 |
| Shavi Estates Ltd | Real estate | 2025 |
| Sheaservices Ltd | Transport & logistics | 2025 |
| Sheers Limited | Construction | 1978 |
| Shelden Plastering Ltd | Construction | 2017 |
| Shepherds Metal Recycling Ltd | Wholesale & retail | 2025 |
| Shergill Property Group Ltd | Real estate | 2025 |
| Shield Development Consultancy Ltd | Real estate | 2021 |
| Shield Security Protection Ltd | Administrative & support | 2026 |
| Shields Coatings Ltd | Manufacturing | 2017 |
| Shift Visuals Ltd | Information & communication | 2021 |
| Ship Morton Limited | Hospitality | 2018 |
| Shiva Hospitality Ltd | Hospitality | 2024 |
| Shockwave App Limited | Information & communication | 2022 |
| Shri Krish Retail Ltd | Wholesale & retail | 2016 |
| Shrivan Consultants Ltd | Health & social care | 2019 |
| Shubble Education Ltd | Education | 2018 |
| Shufflers Inn Ltd | Wholesale & retail | 2021 |
| Shutter Media Limited | Manufacturing | 2011 |
| Si-Raj Restaurants Ltd | Hospitality | 2025 |
| Siciliano Pizzeria Kurt Ltd | Hospitality | 2019 |
| Sickbirds Automobili Ltd | Wholesale & retail | 2020 |
| Sidd Capital Traders Ltd | Information & communication | 2025 |
| Sido Properties 1 Ltd | Real estate | 2024 |
| Siervo Care Limited | Health & social care | 2019 |
| Sighthound Inspection Management Ltd | Other services | 2019 |
| Sign Design Digital Limited | Professional & scientific | 2011 |
| Signage Solutions (GBR) Limited | Administrative & support | 2018 |
| Signature Roofing and Building Ltd | Construction | 2022 |
| Signatures Group Limited | Wholesale & retail | 2018 |
| Significand Limited | Information & communication | 2018 |
| Signtree (Skinnergate) Limited | Other services | 2019 |
| Signtree Electrical (Skinnergate) Limited | Other services | 2019 |
| SIK Pharma Ltd | Wholesale & retail | 2023 |
| Silence Ltd | Wholesale & retail | 2026 |
| Silkriot Limited | Manufacturing | 2025 |
| Sillars Properties Limited | Real estate | 2015 |
| Silver Screen Rentals Limited | Administrative & support | 2025 |
| Silver Street (Bishop Auckland) Residents Association Limited | Households | 2001 |
| Silverdale Court (York) Management Company Limited | Households | 1972 |
| Silverdale GAS Ltd | Construction | 2021 |
| SIM King Ltd | Arts & recreation | 2021 |
| Simfly (Virtual Global Flying) Limited | Arts & recreation | 2021 |
| Simmons Automotive Solutions Ltd | Financial services | 2024 |
| Simon Carson Sports Schools Limited | Education | 2006 |
| Simon Pubs Ltd | Hospitality | 2024 |
| Simoo Ltd | Hospitality | 2024 |
| Simos Pizzeria D Ltd | Hospitality | 2023 |
| Simple Leisure Teesvalley Ltd | Hospitality | 2026 |
| Simple Renovation Ltd | Construction | 2023 |
| Simply Rogue Clothing Ltd | Other services | 2021 |
| Simply Thank YOU (Darlington) Limited | Extraterritorial | 1993 |
| Simply Thank YOU Limited | Wholesale & retail | 2000 |
| Simpson Investment Group Ltd | Financial services | 2025 |
| Sims Estates Limited | Extraterritorial | 2014 |
| SIR E D Walker Trustee | Professional & scientific | 2016 |
| Sirona Polyurethanes Limited | Professional & scientific | 2023 |
| Site 2 Site Solutions Ltd | Transport & logistics | 2021 |
| Six-Key Policy Advisers Limited | Other services | 2010 |
| SJ Systems (North) Ltd | Information & communication | 2016 |
| SJE Logistics Ltd | Professional & scientific | 2024 |
| SK Property Developments NE Ltd | Real estate | 2020 |
| SK Search Limited | Administrative & support | 2007 |
| Skape North East Ltd | Education | 2023 |
| Skerne Limited | Administrative & support | 2016 |
| Skerne Park PUB Ltd | Hospitality | 2023 |
| Skerne Studios Management Limited | Households | 2017 |
| Skin & Tonic Spa Ltd | Other services | 2026 |
| Skin Renaissance Ltd | Health & social care | 2013 |
| Skinnergate Spice Limited | Hospitality | 2019 |
| Skinwalker Limited | Manufacturing | 2019 |
| SKS Medical Limited | Information & communication | 2020 |
| Skulk Ltd | Professional & scientific | 2015 |
| Sky Marquees Ltd | Administrative & support | 2020 |
| Skye Azea Ltd | Information & communication | 2026 |
| Skyhire Ltd | Administrative & support | 2023 |
| SL Bathrooms Limited | Construction | 2008 |
| SL Motorhome Hire Ltd | Administrative & support | 2026 |
| SL Windservices Ltd | Energy | 2026 |
| SLA Cable Solutions Ltd | Construction | 2018 |
| SLC Engineering Limited | Other services | 2018 |
| SLC Leathers Limited | Wholesale & retail | 2023 |
| SLK Developments Limited | Real estate | 2023 |
| SLK Entertainment Limited | Arts & recreation | 2024 |
| SLK Property Group Limited | Real estate | 2026 |
| Sloan Pictures Ltd | Information & communication | 2021 |
| Slovak Taverns Ltd | Hospitality | 2021 |
| Slowper Holdings Ltd | Real estate | 2022 |
| Smada Estates Ltd | Real estate | 2025 |
| Smak Consulting Ltd | Professional & scientific | 2017 |
| Small Firms Enterprise Development Initiative Limited | Education | 1998 |
| Small's Properties Ltd | Real estate | 2023 |