| Stockade Media Limited | Information & communication | 2023 |
| Stockbridge Family Holdings Limited | Financial services | 2025 |
| Stockbridge Trading Limited | Wholesale & retail | 2025 |
| Stockbridge Trading Wholesale Limited | Wholesale & retail | 2025 |
| Stockbrook Investments Limited | Real estate | 2004 |
| Stocklaw Associates Limited | Professional & scientific | 2022 |
| Stocks & Green Ltd | Wholesale & retail | 2020 |
| Stockwell Street Limited | Real estate | 2018 |
| Stockwell Ventures Limited | Real estate | 2018 |
| Stoken Properties Limited | Construction | 2001 |
| Stonard Electrical Limited | Construction | 2020 |
| Stone Angel Property Solutions Ltd | Real estate | 2025 |
| Stone Bowl Limited | Construction | 2024 |
| Stone Lane Holdings Ltd | Real estate | 2025 |
| Stone Lane Residential Development Ltd | Construction | 2025 |
| Stone Panda Ltd | Professional & scientific | 2024 |
| Stone Valley Ltd | Wholesale & retail | 2023 |
| Stonebridge Estates Limited | Real estate | 2026 |
| Stonebridge Services Limited | Construction | 2021 |
| Stonefield Restoration Mixes Limited | Manufacturing | 2013 |
| Stoneham Flat Management Company Limited | Households | 1977 |
| Stoneham GM Limited | Health & social care | 2022 |
| Stonehouse Communications Ltd | Professional & scientific | 2017 |
| Stonemark Construction Ltd | Construction | 2026 |
| Stonemill Kitchens Ltd | Construction | 2017 |
| Stoney Management Services Ltd | Professional & scientific | 2019 |
| Storipedia Media Consulting Limited | Professional & scientific | 2025 |
| Storky Properties Ltd | Real estate | 2026 |
| Storm Dents Limited | Wholesale & retail | 2014 |
| Storm Design and Sourcing Solutions LLP | | 2020 |
| Storm Events Holdings Limited | Financial services | 2023 |
| Storm Fire Limited | Manufacturing | 2024 |
| Storm Group Holdings Limited | Administrative & support | 2019 |
| Storm IR Limited | Information & communication | 2023 |
| Storm Photography Ltd | Professional & scientific | 2004 |
| Stormforce Developments Limited | Wholesale & retail | 2003 |
| Stort Accounting Services Limited | Professional & scientific | 2003 |
| Storycraft Studios Limited | Professional & scientific | 2026 |
| Stour Bay Company Limited | Wholesale & retail | 2006 |
| Stour Bay Partnership Ltd | Professional & scientific | 2011 |
| Stour Bay Recruitment Limited | Administrative & support | 2024 |
| Stour Procurement Ltd | Professional & scientific | 2016 |
| Stour Run Limited | Agriculture & fishing | 2020 |
| Stour Sudbury Limited | Health & social care | 2001 |
| Stour Valley Bar Services Ltd | Hospitality | 2024 |
| Stour Valley Cars Limited | Wholesale & retail | 2012 |
| Stour Valley Construction and Groundworks Limited | Construction | 2007 |
| Stour Valley Freight Ltd | Transport & logistics | 2010 |
| Stour Valley Oak Limited | Construction | 2013 |
| Stour Valley Tax and Accounts Ltd | Professional & scientific | 2022 |
| Stour View Construction Limited | Professional & scientific | 2025 |
| Stour View Court Residents Company Limited | Households | 1992 |
| Stour Windows Limited | Construction | 1982 |
| Stourbank Contracts Ltd | Construction | 2024 |
| Stourgarden Farms Limited | Real estate | 2002 |
| Stourgarden Limited | Wholesale & retail | 1995 |
| Strada (Chelmsford) Management Company Limited | Households | 2005 |
| Straight Forwarding Ltd | Transport & logistics | 2009 |
| Straight Road Community Centre Limited | Real estate | 2003 |
| Straight Road Dental Practice Limited | Administrative & support | 2008 |
| Straight Road Farm Limited | Agriculture & fishing | 2022 |
| Straight Road Property Management Company Limited | Real estate | 2003 |
| STRAT21 Land Partnerships Limited | Construction | 2025 |
| Strata Property Developments Limited | Professional & scientific | 2003 |
| Strategic Growth Partnership Ltd | Professional & scientific | 2025 |
| Strategic Investments Group Limited | Financial services | 2004 |
| Strategic Leadership Academy C.I.C. | Education | 2024 |
| Strategy Drone Limited | Professional & scientific | 2020 |
| Strategy Education Ltd | Administrative & support | 2003 |
| Strategy Enterprise Holdings Ltd | Financial services | 2013 |
| Strategy Recruitment Ltd | Administrative & support | 2013 |
| Strategy Welfare Services Ltd | Administrative & support | 2018 |
| STRATEGY4TECHNOLOGY Limited | Professional & scientific | 2005 |
| Stratford Manor Management Company Limited | Real estate | 1999 |
| Strato Pro Technical Services Ltd | Professional & scientific | 2025 |
| Stratos Services Ltd | Construction | 2025 |
| Stratus Aviation Training Ltd | Education | 2023 |
| Stream Clean Plumbing & Heating Ltd | Construction | 2020 |
| Stream Clean Ventilation Limited | Energy | 2007 |
| Streamchat AI Limited | Information & communication | 2023 |
| Street Farm Properties Limited | Real estate | 2021 |
| Street Wines Limited | Wholesale & retail | 2011 |
| Streetcars Hurst Green Garage Ltd | Wholesale & retail | 2013 |
| Streetify Limited | Other services | 2014 |
| Streetmaster Holdings Limited | Administrative & support | 2002 |
| Streetmaster Limited | Administrative & support | 2001 |
| Streets Ahead Property Consultants Limited | Real estate | 2018 |
| Streetwise Recruitment Limited | Administrative & support | 2015 |
| Streetwork Holdings Ltd | Financial services | 2026 |
| Streetwork Solutions Limited | Administrative & support | 2005 |
| Strengths Unleashed Limited | Administrative & support | 2017 |
| Strike Autographs Ltd | Wholesale & retail | 2015 |
| Strong & Fisher Pensions and Retirement Scheme Trustees Limited | Professional & scientific | 1988 |
| Strongbox Ltd | Other services | 2011 |
| Stronvar Rest Home Ltd | Health & social care | 2013 |
| Strood Scaffolding & Construction Limited | Construction | 2024 |
| Stroymax Construction Limited | Construction | 2021 |
| Structural Movement Solutions Limited | Construction | 2004 |
| Struere Infrastructure Ltd | Construction | 2019 |
| Struvara Ltd | Information & communication | 2026 |