| Stanley Dock Properties Limited | Construction | 2009 |
| Stanley Dock Property Management Company Limited | Administrative & support | 2017 |
| Stanley House Limited | Health & social care | 2006 |
| Stanmore (Freehold) Limited | Construction | 2019 |
| Stanmore Builders Ltd | Construction | 2026 |
| Stanmore Corporation Limited | Financial services | 2024 |
| Stanmore Law Practice Limited | Professional & scientific | 2016 |
| Stanmore Training Academy Ltd | Education | 2025 |
| Star House Limited | Real estate | 1934 |
| Starburn LLP | | 2021 |
| Starchild Pictures Limited | Information & communication | 2010 |
| Starlight International Investments Ltd | Other services | 2017 |
| Starman Productions Ltd | Extraterritorial | 2024 |
| Starproper Ltd | Real estate | 2019 |
| Starry Fashion Limited | Wholesale & retail | 2022 |
| Stars FLY Limited | Transport & logistics | 2002 |
| Startling Music Limited | Information & communication | 1968 |
| Statehouse Limited | Professional & scientific | 2023 |
| Statesman Limited | Administrative & support | 1994 |
| Station Approach (Kings Langley) Residents Company Ltd | Households | 1995 |
| Station Brew Limited | Hospitality | 2016 |
| Stawi Group Limited | Wholesale & retail | 2026 |
| Stayonthesunnyside Pictures Ltd | Information & communication | 2026 |
| Steady Steps Home Ltd | Health & social care | 2025 |
| Stealth Cleaning Ltd | Administrative & support | 2023 |
| Steamrock Asset Management Limited | Administrative & support | 2016 |
| Steamrock Capital Limited | Financial services | 2012 |
| Steamrock Catalyst Developments Limited | Real estate | 2014 |
| Steamrock Catalyst Holdings Limited | Financial services | 2016 |
| Steamrock Catalyst Properties Limited | Real estate | 2016 |
| Steed Advertising Limited | Professional & scientific | 1989 |
| Steene Law Limited | Professional & scientific | 2016 |
| Stef Trans Ltd | Wholesale & retail | 2012 |
| Stefmary Design Ltd | Wholesale & retail | 2020 |
| Steinborn Estates Ltd | Real estate | 2023 |
| Steiner Construction Ltd | Construction | 2025 |
| Steiner Property Services Ltd | Construction | 2018 |
| Stella Mann College of Performing Arts Limited | Arts & recreation | 2008 |
| Stellar Medical Services Ltd | Health & social care | 2021 |
| Stem for Kids Ltd | Education | 2024 |
| Step Digital Group Limited | Information & communication | 2023 |
| Step Digital London Limited | Information & communication | 2019 |
| Stephens West Holdings Limited | Real estate | 2023 |
| Sterling Associates Certified Accountants Limited | Professional & scientific | 2026 |
| Sterling Contracts Limited | Administrative & support | 2017 |
| Sterling Orbit Limited | Financial services | 2020 |
| Stern Fleet Management & Co Limited | Wholesale & retail | 2024 |
| Steve & Martin's Precious Pet Services Ltd | Other services | 2018 |
| Stevensons Estates Limited | Real estate | 2017 |
| Sticker Agency Limited | Information & communication | 2018 |
| Stirling Court Property Company Ltd | Households | 2015 |
| STK Property Solutions Ltd | Manufacturing | 2020 |
| STM Technologies Limited | Information & communication | 2017 |
| Stockdale Design Limited | Professional & scientific | 2014 |
| Stokon Properties Limited | Real estate | 2026 |
| Stoll Construction Limited | Real estate | 1980 |
| Stone Propco Limited | Real estate | 2026 |
| Stonefield 88 Ltd | Real estate | 2025 |
| Stonemill Investments Ltd | Financial services | 2026 |
| Stoneview Consultancy Ltd | Transport & logistics | 2020 |
| Stoninton Ltd | Professional & scientific | 2015 |
| Stonybrook Limited | Professional & scientific | 1996 |
| Storage 4 Wheelie Bins Limited | Manufacturing | 2019 |
| Storesrealm Limited | Wholesale & retail | 1978 |
| Stori Digital Limited | Professional & scientific | 2017 |
| Storm Prop Ltd | Real estate | 2024 |
| Storr Productions Limited | Professional & scientific | 2010 |
| Stortford Fields (Parcel a) Management Company Limited | Households | 2024 |
| Story Please Limited | Information & communication | 2024 |
| Stour Project Services Ltd | Construction | 2017 |
| Stow Holdings Limited | Professional & scientific | 2024 |
| Strada Media Limited | Information & communication | 2008 |
| Strapatsada Ltd | Health & social care | 2025 |
| Strat Software Limited | Information & communication | 2016 |
| Strata Aviation Services Limited | Transport & logistics | 2017 |
| Strategic Change Consulting Services Ltd | Other services | 2022 |
| Strategy Stone Ltd | Other services | 2016 |
| Stratfield Ltd | Real estate | 2021 |
| Stratfield Property Limited | Wholesale & retail | 2021 |
| Stratton Close Properties Limited | Households | 1981 |
| Stratulator Limited | Real estate | 2022 |
| Strauss Phillips & Co. Limited | Professional & scientific | 2017 |
| Strawberries and Hearts Limited | Arts & recreation | 2014 |
| Strawberry Blond Ltd | Information & communication | 2015 |
| Streaming Limited | Information & communication | 2008 |
| Streetdogs Pet Groomers Limited | Other services | 2021 |
| Strength Celebrity Bournemouth Limited | Other services | 2024 |
| Strength Properties Limited | Construction | 2020 |
| Strength Property Limited | Administrative & support | 2019 |
| Strength Slipend Limited | Other services | 2023 |
| Strength Waterhall Ltd | Real estate | 2024 |
| Stretto Music Limited | Arts & recreation | 2013 |
| Strike 1 Demo Ltd | Information & communication | 2012 |
| STRIKE2 Unlimited | Professional & scientific | 2013 |
| Striking Electrical Limited | Construction | 2019 |
| Stripe 21 Limited | Information & communication | 2002 |
| Strode Developments Ltd | Real estate | 2022 |
| Strode Developments SUB Limited | Real estate | 2024 |
| Stroke I.T. Limited | Administrative & support | 2014 |
| Structivo Limited | Construction | 2026 |