| STH International Educational and Tourism Consultancy Ltd | Administrative & support | 2025 |
| STI International Ltd | Hospitality | 2025 |
| Stile Sartoriale Ltd | Other services | 2015 |
| Stilewalk Services Limited | Professional & scientific | 2022 |
| Still Waters Consulting Ltd | Professional & scientific | 2025 |
| Stillwaters House Limited | Real estate | 2022 |
| Stilo International Limited | Professional & scientific | 1999 |
| Stilo Technology Limited | Information & communication | 1995 |
| Stinton Window Cleaners Limited | Administrative & support | 2011 |
| Stirling Capital Partners Ltd | Real estate | 2025 |
| Stirling-Luxe Limited | Real estate | 2022 |
| Stitch Consultancy Ltd | Professional & scientific | 2024 |
| STJ Media Ltd | Information & communication | 2025 |
| Stjohnstone Ltd | Manufacturing | 2026 |
| STK 3 Limited | Wholesale & retail | 2026 |
| Stmar Ltd | Manufacturing | 2026 |
| Stmeta Technologies Ltd | Information & communication | 2026 |
| Stmtfl Ltd | Real estate | 2013 |
| STN Brickwork Ltd | Construction | 2024 |
| Stock Images Limited | Extraterritorial | 2011 |
| Stock Point UK Ltd | Wholesale & retail | 2025 |
| Stock Right NOW Limited | Information & communication | 2014 |
| Stockslord Ltd | Manufacturing | 2024 |
| Stockwell Kitchens & Bathrooms Ltd | Construction | 2021 |
| Stockwell Property Limited | Real estate | 2017 |
| Stoke Ideal Estates,Limited | Real estate | 1928 |
| Stoke View Advisory Ltd | Professional & scientific | 2022 |
| Stone Electrical Southern Ltd | Construction | 2020 |
| Stone Holdings Group UK Ltd | Agriculture & fishing | 2022 |
| Stone Pier Marina Management Ltd | Transport & logistics | 2023 |
| Stone Pier Yard Limited | Financial services | 2011 |
| STONE4HOMES Limited | Construction | 2013 |
| Stoneacre Consultancy Services Ltd | Professional & scientific | 2024 |
| Stonebridge Partnership Ltd | Administrative & support | 2019 |
| Stonebrook Financials Limited | Financial services | 2022 |
| Stonechats Software Limited | Information & communication | 1992 |
| Stonecold Ventures Ltd | Financial services | 2025 |
| Stoneflat Assets Limited | Administrative & support | 2011 |
| Stoneham Carpentry Limited | Construction | 2018 |
| Stoneham Golf Club Limited | Other services | 2023 |
| Stoneham Golf Company,Limited(The) | Real estate | 1908 |
| Stoneham Health Limited | Professional & scientific | 2022 |
| Stonehealth Limited | Manufacturing | 1989 |
| Stonelands Cavaliers RTM Company Limited | Households | 2009 |
| Stoneline Paving and Roofing Ltd | Construction | 2025 |
| Stoneman Electrical Services Limited | Energy | 2014 |
| Stonepass Limited | Professional & scientific | 2019 |
| Stonewater Bathrooms Limited | Extraterritorial | 2024 |
| Stonewater Close Management Company Limited | Households | 2019 |
| Stoneworks (UK) Limited | Manufacturing | 1995 |
| Stonymoor 4 Ways Management Company Limited | Households | 2021 |
| Storage Advisory Centre Limited | Professional & scientific | 1978 |
| Storage on Site (Sales) Limited | Wholesale & retail | 2014 |
| Storage on Site Group Limited | Financial services | 2020 |
| Storage on Site Limited | Wholesale & retail | 2006 |
| Storage People Ltd | Information & communication | 2023 |
| Storaway Limited | Administrative & support | 2001 |
| Store Cell Ltd | Professional & scientific | 2018 |
| Storepoint Limited | Real estate | 2026 |
| Stork Deliveries (UK) Limited | Transport & logistics | 2007 |
| Storm Guard Solutions Limited | Administrative & support | 2025 |
| Storm Hair Limited | Other services | 2014 |
| Stormbird Ltd | Hospitality | 2011 |
| Stormbourne Estates Ltd | Real estate | 2024 |
| Stormbourne Holdings Ltd | Financial services | 2025 |
| Stormgorm Electrical Ltd | Construction | 2025 |
| Stormhaven Bunker C.I.C. | Administrative & support | 2024 |
| Stormhaven Escapes Ltd | Arts & recreation | 2024 |
| Story Hero Ltd | Information & communication | 2020 |
| Storyworks Plus Ltd | Information & communication | 2023 |
| Storyworks Two Ltd | Information & communication | 2026 |
| Stovebook Ltd | Wholesale & retail | 2017 |
| Stow Away Storage Limited | Transport & logistics | 2004 |
| Straddle UK Ltd | Administrative & support | 2024 |
| Stradina Limited | Hospitality | 2019 |
| Straight Edge Plastering Ltd | Construction | 2026 |
| Straight Talk Estate Planning Ltd | Financial services | 2019 |
| Straight Talk Financial Planning Ltd | Financial services | 2006 |
| Stralt Decorating Limited | Construction | 2024 |
| Stran Building Systems Limited | | 1990 |
| Strand Bioinformatics Ltd | Professional & scientific | 2025 |
| Strandhill Property Development Limited | Construction | 2006 |
| Strandhill, Civil Engineering Limited | Construction | 1994 |
| Strandway Limited | Professional & scientific | 1992 |
| Strange Tool Store Ltd | Information & communication | 2020 |
| Stratagem Defence Limited | Professional & scientific | 2023 |
| Stratawise Ltd | Professional & scientific | 2025 |
| Strategic Unity Limited | Professional & scientific | 2017 |
| Strategy Carpentry & Building Ltd | Manufacturing | 2026 |
| Stratford News and Media Ltd | Extraterritorial | 2020 |
| Stratfords Commercial (Andover) Limited | Administrative & support | 1987 |
| Stratfords Commercial Limited | Financial services | 1987 |
| Stratiform Partners Ltd | Professional & scientific | 2026 |
| Stratlytics.Iq Limited | Hospitality | 2025 |
| Stratos 12 LLP | | 2025 |
| Stratum House Group Ltd | Health & social care | 2024 |
| Stratus Financial Consultants Limited | Professional & scientific | 2020 |
| Straus Food and Drink Limited | Manufacturing | 2020 |
| Straw HAT Social Ltd | Information & communication | 2023 |
| Stream PAY Solutions Limited | Professional & scientific | 2024 |