| Shona Care Solutions Ltd | Health & social care | 2023 |
| Shoobz Ltd | Wholesale & retail | 2025 |
| Shook Media Limited | Information & communication | 2024 |
| Shootcert Ltd | Health & social care | 2021 |
| Shooz 4U Ltd | Wholesale & retail | 2016 |
| Shop Genius Limited | Wholesale & retail | 2024 |
| Shop Link Ltd | Wholesale & retail | 2024 |
| Shopelis Limited | Wholesale & retail | 2025 |
| Shopfit Limited | Construction | 1998 |
| Shopilite Ltd | Wholesale & retail | 2024 |
| SHOPNEST-5 Ltd | Wholesale & retail | 2026 |
| Shoreline Capital Ltd | Real estate | 2020 |
| Short Electrical Ltd | Construction | 2011 |
| Shortcuts Nikki Ltd | Other services | 2020 |
| Shortland Associates Limited | Professional & scientific | 2018 |
| Shortland Construction Limited | Construction | 2004 |
| Shosoccer FC Limited | Education | 2025 |
| Showmeduk Limited | Health & social care | 2007 |
| Showoff Communications Limited | Professional & scientific | 2017 |
| Shpresa Ltd | Hospitality | 2026 |
| SHR Solutions Ltd | Wholesale & retail | 2022 |
| Shred Cycle Limited | Water & waste | 2017 |
| Shreek Meds Limited | Wholesale & retail | 2018 |
| Shreya Tech Ltd | Information & communication | 2017 |
| Shrihari Parshva Ltd | Wholesale & retail | 2019 |
| Shrk Property Limited | Real estate | 2022 |
| SHT Digital Media Ltd | Transport & logistics | 2025 |
| Shumaila Ashraf Ltd | Wholesale & retail | 2026 |
| Shumi Limited | Construction | 2018 |
| Shutter Spec Security Ltd | Construction | 2021 |
| SIA Digital Limited | Professional & scientific | 2025 |
| SIA UK Properties Ltd | Real estate | 2024 |
| Siah Goldenmoments Ltd | Health & social care | 2025 |
| Siamdaraje Limited | Real estate | 2025 |
| Sian Group Homes Limited | Health & social care | 2025 |
| Siara Private Limited | Real estate | 2024 |
| Sibb Consulting Ltd | Information & communication | 2018 |
| Sibley Plastering Contractors Ltd | Construction | 2022 |
| Sick Framez Limited | Professional & scientific | 2019 |
| Sidgrace Group Ltd | Wholesale & retail | 2020 |
| Sidhu Vans Ltd | Transport & logistics | 2025 |
| Sidi Maarouf Ltd | Hospitality | 1996 |
| Sidner Capital Ltd | Construction | 2022 |
| Sidner CBS Limited | Construction | 2023 |
| Sidonia Limited | Professional & scientific | 2020 |
| Sidos Associates Limited | Professional & scientific | 2022 |
| Siera Stone Limited | Construction | 2009 |
| Sierra IT Training Services Limited | Information & communication | 2008 |
| SIG Plumbing Ltd | Construction | 2024 |
| Sight and Sound Technology Limited | Information & communication | 1979 |
| Sigma Accountax Ltd | Information & communication | 2020 |
| Sigma Consultant Services Limited | Professional & scientific | 2018 |
| Sigma Maintenance Ltd | Construction | 2024 |
| Sigma Thirty Three Limited | Information & communication | 2019 |
| Sign in App Limited | Information & communication | 2013 |
| Sign Logic Ltd | Professional & scientific | 2014 |
| Sign UP Training Ltd | Education | 2025 |
| Signature Buildworks Ltd | Construction | 2025 |
| Signature Embroidery Ltd | Wholesale & retail | 2020 |
| Signature Luxury Interiors Limited | Professional & scientific | 2018 |
| Signature Playgrounds Ltd | Construction | 2022 |
| Signature Spaces Property Developers Ltd | Construction | 2025 |
| Signature Surfaces Northants Ltd | Construction | 2026 |
| Signature Wardrobes Ltd | Manufacturing | 2026 |
| Signed and Completed Ltd | Administrative & support | 2025 |
| Signline MK Limited | Manufacturing | 2011 |
| Signor Verde Ltd | Hospitality | 2020 |
| SIGNS2STICK Ltd | Manufacturing | 2026 |
| SIGNS@86 Ltd | Manufacturing | 2020 |
| Sihiya International Ltd | Real estate | 2023 |
| Sikabon Limited | Health & social care | 2015 |
| Silax Ltd | Professional & scientific | 2022 |
| Silbury Golf 2020 Limited | Arts & recreation | 2019 |
| Silent Nights Entertainment Ltd | Information & communication | 2020 |
| Silent Vale Limited | Wholesale & retail | 2018 |
| Silesia Trans Ltd | Transport & logistics | 2016 |
| Silk by Design UK Ltd | Wholesale & retail | 2018 |
| Silk Foods Limited | Extraterritorial | 2007 |
| Silk Ribbon Studio Ltd | Professional & scientific | 2026 |
| Silka.Herb Ltd | Wholesale & retail | 2024 |
| Silkline Holdings Limited | Financial services | 2020 |
| Silkline Trading Company Limited | Real estate | 1992 |
| Silky Trends and Treats Limited | Manufacturing | 2021 |
| Silva Ltd | Wholesale & retail | 2023 |
| Silva Maris Ltd | Agriculture & fishing | 2019 |
| Silver Atlas Ltd | Information & communication | 2026 |
| Silver Bullet Repairs Ltd | Construction | 2016 |
| Silver Close Management Company Ltd | Households | 2019 |
| Silver Crest Models Limited | Manufacturing | 2010 |
| Silver FOX Transport Limited | Transport & logistics | 2009 |
| Silver Linings Podiatry Limited | Health & social care | 2018 |
| Silver Service 2019 Ltd | Transport & logistics | 2005 |
| Silver Street Pubco Ltd | Hospitality | 2019 |
| SILVER7 Mapping Limited | Professional & scientific | 2008 |
| Silverback (UK) Ltd | Professional & scientific | 2008 |
| Silverfoil Medical Services Limited | Health & social care | 2022 |
| Silverfox Building Surveys Ltd | Professional & scientific | 2021 |
| Silvergate Group Holdings Limited | Professional & scientific | 2015 |
| Silvergate Media Creature Cases Limited | Information & communication | 2017 |
| Silvergilt Limited | Wholesale & retail | 2003 |