| Sitwell Estates NO 4 Company Limited | Extraterritorial | 2023 |
| Sius Consulting Ltd | Administrative & support | 2017 |
| SIX Audio Limited | Information & communication | 2018 |
| SIX Daisy Ltd | Wholesale & retail | 2025 |
| SIX Degrees Traffic Management Ltd | Professional & scientific | 2023 |
| SIX Degrees Transport Ltd | Professional & scientific | 2021 |
| SIX/36 Ltd. | Professional & scientific | 2013 |
| Sixa Global Ltd | Wholesale & retail | 2025 |
| Sixandahalf Ltd | Hospitality | 2024 |
| SIXTY4 Limited | Arts & recreation | 2004 |
| Sixtynine Limited | Hospitality | 2023 |
| Siyam Capital Limited | Professional & scientific | 2013 |
| Sizm Enterprises Limited | Real estate | 2016 |
| SIZZLEREXPRESS286 Limited | Hospitality | 2025 |
| SJ Bookkeeping Ltd | Professional & scientific | 2020 |
| SJ Car Care Limited | Wholesale & retail | 2015 |
| SJ Devonshire Limited | Professional & scientific | 2010 |
| SJ Manchester Limited Partnership | | 2021 |
| SJ Otten Training & Consultancy Ltd | Education | 2024 |
| SJA UK Properties Limited | Real estate | 2023 |
| Sjaw Limited | Wholesale & retail | 2020 |
| SJE Dogs Ltd | Agriculture & fishing | 2019 |
| SJE Tyres Ltd | Wholesale & retail | 2015 |
| Sjeb Holdings Limited | Professional & scientific | 2023 |
| SJG Management Consulting Ltd | Information & communication | 2024 |
| SJJ Pubs Ltd | Hospitality | 2025 |
| SJM (Nominee) Limited | Real estate | 2021 |
| SJM Catering Ltd | Hospitality | 2025 |
| SJM European Transport Services Limited | Transport & logistics | 2019 |
| SJM GP Limited | Real estate | 2021 |
| SJM Strategies Ltd | Administrative & support | 2006 |
| SJN Nutrition Ltd | Health & social care | 2016 |
| SJR Pubs Limited | Hospitality | 2025 |
| SJS Beauty Ltd | Other services | 2023 |
| SJS E&I Services Limited | Construction | 2016 |
| SJS Sheffield Aesthetics Limited | Health & social care | 2014 |
| Sjsw Investments Ltd | Real estate | 2026 |
| SJT Building & Joinery Ltd | Construction | 2009 |
| SK Amrit Properties Ltd | Real estate | 2025 |
| SK Cellar & Co Ltd | Wholesale & retail | 2024 |
| SK Estates Group Ltd | Real estate | 2026 |
| SK Interiors NT CIC | Professional & scientific | 2025 |
| SK Medical Group Ltd | Health & social care | 2024 |
| SK Motors (SY) Ltd | Wholesale & retail | 2023 |
| SK Physiotherapy Limited | Other services | 2015 |
| SK Taxis Ltd | Transport & logistics | 2017 |
| SK Transit Ltd | Transport & logistics | 2026 |
| SK Welding Limited | Professional & scientific | 2018 |
| Sk-Uk Management Ltd | Other services | 2018 |
| Skaadi Ltd | Education | 2026 |
| Skapa Digital Solutions Ltd | Information & communication | 2025 |
| Skateboard England | Arts & recreation | 2015 |
| Skateboard GB Limited | Arts & recreation | 2017 |
| SKB Beauty (South Yorkshire) Limited | Other services | 2026 |
| SKB Electrical Services Limited | Construction | 2007 |
| Skcif Limited | Health & social care | 2024 |
| Skedaddle Theatre Ltd | Arts & recreation | 2024 |
| Skeet + Coutie Architecture Ltd | Professional & scientific | 2016 |
| SKF Installations Limited | Construction | 2019 |
| SKH Automotive Ltd | Wholesale & retail | 2021 |
| SKI Racing Supplies Limited | Wholesale & retail | 2019 |
| Ski&B Ltd | Wholesale & retail | 2024 |
| SKILL4 Limited | Education | 1999 |
| Skills GAP Training Ltd | Education | 2026 |
| Skills Solutions Group Ltd | Education | 2025 |
| SKILLS4FUTURES Limited | Administrative & support | 2016 |
| Skillslogic Ltd | Information & communication | 2012 |
| Skin Revitalise Ltd | Health & social care | 2013 |
| Skin Sanctuary by Becca Ltd | Other services | 2024 |
| Skin-Vive Ltd | Other services | 2025 |
| Skinn Studio Limited | Other services | 2021 |
| Skinner Steels Limited | Extraterritorial | 2014 |
| Skipper of Halesowen Limited | | 1946 |
| Skirrow Property Services Limited | Real estate | 2023 |
| SKJ Vasir Ltd | Health & social care | 2025 |
| Skjb Courier Services Ltd | Transport & logistics | 2011 |
| Skmukka Limited | Information & communication | 2023 |
| SKN Technology Limited | Professional & scientific | 2017 |
| Sknbyfay Ltd | Other services | 2024 |
| Skot Limited | Professional & scientific | 2008 |
| Skot Properties Limited | Real estate | 2009 |
| SKP Events Ltd | Arts & recreation | 2024 |
| SKP Trading UK Limited | Hospitality | 2022 |
| Skreenx Limited | Information & communication | 2025 |
| Skribes Inventory Specialists Ltd | Administrative & support | 2013 |
| SKS Property Services Ltd | Construction | 2017 |
| Sktj Hospitality Ltd | Hospitality | 2022 |
| SKW Group Limited | Wholesale & retail | 2024 |
| Skwiot Property Ltd | Real estate | 2019 |
| Sky Chemicals (UK) Limited | Manufacturing | 2010 |
| Sky Chemicals Hygiene Ltd | Wholesale & retail | 2014 |
| Sky Line Ocean Properties Limited | Real estate | 2025 |
| Sky Link Tech Limited | Wholesale & retail | 2025 |
| Sky Railing Ltd | Manufacturing | 2018 |
| Sky State Limited | Other services | 2024 |
| Sky Vibe Ltd | Wholesale & retail | 2025 |
| Sky-House (FOX Valley) Management Company Limited | Households | 2021 |
| Sky-House Co. (Copper ST) Ltd | Construction | 2023 |
| Sky-House Co. (FOX Valley) Limited | Construction | 2004 |
| Sky-House Co. (Killamarsh) Limited | Real estate | 2021 |