| Stonequest Limited | | 1972 |
| Stonetrend LP | | 2017 |
| Stonyprojects Ltd | Construction | 2021 |
| Stop Drip Plumbing and Heating Ltd | Construction | 2024 |
| Storer Consulting Limited | Information & communication | 2015 |
| Stork and the Bees CIC | Administrative & support | 2024 |
| Storm Autoworks Limited | Wholesale & retail | 2020 |
| Storm Golf Ltd | Extraterritorial | 2024 |
| Storm Procurement Limited | Mining & quarrying | 2006 |
| Storm Software Systems Ltd | Information & communication | 2023 |
| Storm Technologies Group Limited | Information & communication | 2018 |
| Storm Technologies Limited | Information & communication | 2000 |
| Storm Trademarks Limited | Administrative & support | 2023 |
| Stormbourne Ltd | Professional & scientific | 2021 |
| Stormy Petrel Consulting Limited | Information & communication | 2014 |
| Story Wonder Ltd | Information & communication | 2020 |
| Storyboard Action Concepts Limited | Information & communication | 2016 |
| Storymix Limited | Information & communication | 2019 |
| Storymix Plots Limited | Information & communication | 2023 |
| Stovare Estates Limited | Administrative & support | 2014 |
| Strada Noir Limited | Wholesale & retail | 2026 |
| Strada Prestige Ltd | Wholesale & retail | 2025 |
| Strada Products Limited | Wholesale & retail | 2023 |
| Straight Away Limited | Information & communication | 2015 |
| Straight Knowing Projections Ltd | Construction | 2016 |
| Straight UP Rigging Ltd | Construction | 2025 |
| Straightfix Ltd | Construction | 2024 |
| Stranova Ltd | Professional & scientific | 2023 |
| Strategem (International) Limited | Administrative & support | 2013 |
| Strategic Holdings 1 Ltd | Financial services | 2024 |
| Strategic Property 1 Ltd | Real estate | 2024 |
| Strategic Wills 1 Ltd | Professional & scientific | 2023 |
| Strategix Learning Solutions Ltd | Education | 2024 |
| Strategy One Finance Ltd | Professional & scientific | 2022 |
| Stratford Lodge (Watford) Management Company Limited | Real estate | 1975 |
| Stratford Productions Ltd | Arts & recreation | 2019 |
| Stratify International Ltd | Professional & scientific | 2024 |
| Stratlytics Ltd | Information & communication | 2020 |
| Stratolync Ltd | Information & communication | 2025 |
| Stratrisk Consult (UK) Ltd. | Professional & scientific | 2016 |
| Stratstar Electrical Solutions Ltd | Construction | 2024 |
| Stray Walk Limited | Administrative & support | 2006 |
| Streamkit Ltd | Information & communication | 2015 |
| Streamline Investments Limited | Wholesale & retail | 2003 |
| Streat Fest Ltd | Hospitality | 2024 |
| Street & Spice Catering Ltd | Hospitality | 2024 |
| Streetkids Matter Empowerment Foundation | Education | 2025 |
| Strengtheningattachments Ltd | Health & social care | 2021 |
| Stretch Codes Ltd | Information & communication | 2018 |
| Stretch Therapy London Ltd. | Other services | 2016 |
| Strettson Limited | Administrative & support | 2009 |
| Strictly Personal Ltd | Arts & recreation | 2025 |
| Strides Arcolab International Ltd | Administrative & support | 2004 |
| Strides Global Consumer Healthcare Limited | Manufacturing | 2018 |
| Strides Pharma Global (UK) Ltd | Wholesale & retail | 2015 |
| Strides Pharma UK Ltd | Manufacturing | 1993 |
| Stringers Electrical Ltd | Manufacturing | 2023 |
| Stronghold Plant Ltd | Administrative & support | 2024 |
| Stronghold Structures Limited | Construction | 2013 |
| Structech Engineering Ltd | Construction | 2025 |
| Structural Examinations Ltd | Professional & scientific | 2024 |
| Structural Services Ltd | Construction | 2026 |
| Structural Steelwork Erections Limited | Extraterritorial | 2019 |
| Structural Steelworks & Engineering Limited | Manufacturing | 1994 |
| Struxis Ltd | Professional & scientific | 2025 |
| Stuart Rosenberg LLP | | 2010 |
| Stuart Scott Consulting Limited | Professional & scientific | 2011 |
| Stuart Smith Planner Ltd | Professional & scientific | 2015 |
| Stuart Woolsey Limited | Construction | 2007 |
| Studio 17 Dance Academy Ltd | Education | 2025 |
| Studio Aftervino Limited | Professional & scientific | 2025 |
| Studio Broatch Ltd | Professional & scientific | 2025 |
| Studio Grundy Ltd. | Information & communication | 2022 |
| Studio Pretty Ltd | Professional & scientific | 2011 |
| Studio Rats Ltd | Information & communication | 2023 |
| Studio Vesna Ltd | Information & communication | 2022 |
| Studio Way Management Limited | Real estate | 1985 |
| Studios 6 Limited | Information & communication | 2025 |
| Stumble Property Ltd | Real estate | 2026 |
| Sturm Consulting Limited | Professional & scientific | 2024 |
| Style Sofa Limited | Manufacturing | 2016 |
| Style Travel Executive Limited | Transport & logistics | 2024 |
| Styledge Group Ltd | Construction | 2021 |
| Styling by Soph Ltd | Other services | 2025 |
| Stylographics Limited | Manufacturing | 1996 |
| Styx Marketing Limited | Information & communication | 2014 |
| Sublime Fusion Ltd | Information & communication | 2011 |
| Sublime Stays Ltd | Hospitality | 2019 |
| Submitselect Limited | Wholesale & retail | 1993 |
| Subsea Offshore Consulting Ltd | Professional & scientific | 2023 |
| Substrata Consulting Limited | Education | 2023 |
| Success Appointments Limited | Administrative & support | 1988 |
| Success Digital Limited | Professional & scientific | 1991 |
| Success Property Invest Ltd. | Other services | 2013 |
| Successtalent Limited | Administrative & support | 2020 |
| Sudbury DRY Lining Group Ltd | Construction | 2020 |
| Sudbury Plastering Services Limited | Construction | 1988 |
| Sudofox Ltd | Information & communication | 2022 |
| SUE Massey HR Consulting Ltd | Administrative & support | 2025 |
| Sufiyan Restaurant and Catering Ltd | Hospitality | 2021 |