| Sky-House Co. (Oughtibridge Mill) Limited | Construction | 2019 |
| Sky-House Co. (Oughtibridge Mill) Management Limited | Households | 2021 |
| Sky-House Co. (Smithfield) Limited | Construction | 2026 |
| Sky-House Co. (Sylvester Gardens) Limited | Construction | 2025 |
| Sky-House Co. (Waverley) Limited | Real estate | 2016 |
| Sky-House Co. (Waverley) Management Limited | Real estate | 2019 |
| Sky-House Co. (White Rose) Limited | Real estate | 2020 |
| Sky-House Co. (White Rose) Management Limited | Households | 2021 |
| Sky-House Co. Limited | Construction | 2019 |
| Sky-House Construct Limited | Construction | 2015 |
| Sky-House Waverley Central Management Company Limited | Households | 2025 |
| Skycrest Properties Ltd | Real estate | 2024 |
| Skydiv Ltd | Information & communication | 2026 |
| Skyedgeco Ltd | Wholesale & retail | 2025 |
| Skyforge Consulting Ltd | Information & communication | 2026 |
| Skyguard Property Partners Ltd | Real estate | 2024 |
| Skyguard Roofing Solutions Ltd | Construction | 2024 |
| Skyhook Coaching Limited | Education | 2014 |
| Skykey Properties Ltd | Real estate | 2025 |
| Skyland Education Limited | Administrative & support | 2024 |
| Skylark Engineering Services Ltd | Information & communication | 2018 |
| Skylight Bar and Club Ltd | Hospitality | 2026 |
| Skyline Asset Holdings Ltd | Real estate | 2023 |
| Skyline Circus Limited | Education | 2024 |
| Skyline Conservatory Roof Systems Limited | Construction | 2006 |
| Skyline Construction Services Ltd | Construction | 2024 |
| Skyline Control Systems Ltd | Professional & scientific | 2020 |
| Skyline Gymnastics CIC | Education | 2025 |
| Skyline Suite Inc. Limited | Households | 2024 |
| Skylion Projects Ltd | Construction | 2019 |
| Skyship Housing Limited | Health & social care | 2016 |
| Skytrain Aviation Limited | Transport & logistics | 2011 |
| Skyvia Property Ltd | Real estate | 2025 |
| Skywalk Media Ltd | Construction | 2019 |
| SL Advisory Limited | Education | 2014 |
| SL Education Limited | Education | 2014 |
| SL Engineering Consultancy Ltd | Administrative & support | 2024 |
| SL1NGERS Ltd | Wholesale & retail | 2026 |
| SLA Design (UK) LLP | | 2012 |
| SLA Design Planning Limited | Professional & scientific | 2020 |
| SLA Design Technical LLP | | 2020 |
| SLA Investments Limited | Administrative & support | 2012 |
| Slab Software Ltd | Information & communication | 2026 |
| Slack Capital Limited | Real estate | 2024 |
| Slack Group Limited | Professional & scientific | 2024 |
| Slack Properties Ltd | Real estate | 2024 |
| Slackjaw Film Limited | Information & communication | 2003 |
| Slambarz CIC | Education | 2023 |
| Slaney Bay Limited | Information & communication | 2022 |
| Slanted & Enchanted Ltd | Arts & recreation | 2024 |
| Slate Horse Limited | Information & communication | 2015 |
| Slater Brothers (Sheffield) Limited | Real estate | 1931 |
| Slater Consulting Services Limited | Health & social care | 2018 |
| Slater Sheet Metal Limited | Manufacturing | 1989 |
| Slater Woodhouse Developments Limited | Construction | 2024 |
| Slaters Holding Group Limited | Financial services | 2020 |
| Slaters Lettings Limited | Real estate | 2024 |
| Slaters Management Services Limited | Real estate | 2021 |
| Slater’S Interior Solution Ltd | Construction | 2024 |
| Slattery Anaesthesia Services Limited | Health & social care | 2022 |
| Slattery's Butchers Limited | Wholesale & retail | 2002 |
| Slava Foods Limited | Hospitality | 2025 |
| Slayleigh Commercial Limited | Professional & scientific | 2014 |
| SLB Deals Ltd | Wholesale & retail | 2024 |
| Sldean Estates Ltd | Real estate | 2019 |
| Sldtechnical (Dorset) Limited | Construction | 2024 |
| SLE Housing Ltd | Households | 2017 |
| SLE Residential Limited | Real estate | 2015 |
| Sleath Limited | Professional & scientific | 2007 |
| Sleeki Ltd | Wholesale & retail | 2025 |
| Sleep Vitality Ltd | Health & social care | 2019 |
| Sleep Well Enjoy Life Limited | Wholesale & retail | 2007 |
| Sleepcogni Limited | Manufacturing | 2018 |
| Sleeper Music Limited | Arts & recreation | 2017 |
| Sleepezy Ltd | Hospitality | 2020 |
| Sleeps Trading Limited | Wholesale & retail | 2019 |
| Sleigh Support Services Ltd | Administrative & support | 2024 |
| Slej Properties Limited | Real estate | 2025 |
| Slender Fit Ltd | Manufacturing | 2024 |
| SLF Property Limited | Real estate | 2023 |
| Slice of Wild Ltd | Manufacturing | 2022 |
| Slice Solutions Ltd | Professional & scientific | 2024 |
| Slices City Road Ltd | Hospitality | 2026 |
| Slick Duck Ltd | Information & communication | 2022 |
| Sling Spot Ltd | Wholesale & retail | 2016 |
| Slipstream Effects Limited | Hospitality | 2023 |
| SLL Recruitments Limited | Administrative & support | 2020 |
| SLM Engineering Limited | Professional & scientific | 2020 |
| Slopexi Ltd | Wholesale & retail | 2026 |
| Slov Mart Foods Limited | Construction | 2019 |
| Slovakia Shop Ltd | Wholesale & retail | 2026 |
| Slow Limited | Administrative & support | 2024 |
| SLR Commercial Limited | Other services | 2015 |
| SLR Medical Ltd | Health & social care | 2023 |
| SLR Outlets Limited | Other services | 2015 |
| Slra UK Ltd | Administrative & support | 2025 |
| Slsy Ltd | Hospitality | 2024 |
| SLT Remapping and Diagnostics Ltd | Wholesale & retail | 2008 |
| Slug Art Ltd | Arts & recreation | 2014 |
| Slugger Distribution Ltd | Wholesale & retail | 2012 |