| Sweet Marketing and Design Limited | Construction | 2012 |
| Sweet Offer Ltd | Hospitality | 2026 |
| Sweet Panda (Dewsbury) Ltd | Hospitality | 2018 |
| Sweet PEE Ltd | Manufacturing | 2025 |
| Sweet Tradition Limited | Wholesale & retail | 2011 |
| Sweetie Desserts Ltd | Hospitality | 2020 |
| SWEETSYMPHONY2025 Ltd | Manufacturing | 2025 |
| Swfc Community Programme Holdings Limited | Administrative & support | 2021 |
| SWG Enterprises Limited | Administrative & support | 2002 |
| Swift 1896 Limited | | 1986 |
| Swift BTL Ltd | Real estate | 2020 |
| Swift Enterprise Group Limited | Financial services | 2019 |
| Swift Fit Autos Ltd | Wholesale & retail | 2025 |
| Swift GAS Limited | Construction | 2021 |
| Swift Holdings & Marketing Ltd | Financial services | 2023 |
| Swift Learning Consultancy Limited | Information & communication | 2025 |
| Swift Levick Magnets | Extraterritorial | 1982 |
| Swift Motor Solution Limited | Wholesale & retail | 2020 |
| Swift Plant Services Ltd | Wholesale & retail | 2023 |
| Swift Plant Spares Limited | Wholesale & retail | 1980 |
| Swift Property & Investments Ltd | Real estate | 2022 |
| Swift Realisation Limited | Professional & scientific | 2021 |
| Swift Residences Ltd | Real estate | 2025 |
| Swift Signal Solutions Ltd | Construction | 2023 |
| Swift SME Hub Limited | Information & communication | 2022 |
| Swift Solutons Limited | Transport & logistics | 2024 |
| Swift Sykes Ltd | Professional & scientific | 2023 |
| Swifta Beater Limited | Information & communication | 2016 |
| Swiftinn Stays Ltd | Real estate | 2024 |
| Swiftly Transport Ltd | Transport & logistics | 2025 |
| Swiftprinting Limited | Wholesale & retail | 2012 |
| Swiftswipper Ltd | Administrative & support | 2026 |
| Swimyourswim Ltd | Arts & recreation | 2014 |
| Swing Ting Records Limited | Information & communication | 2016 |
| Swini Solutions Limited | Real estate | 2010 |
| Swinston Hill Ltd | Health & social care | 2025 |
| Swinston Hill Meadows Limited | Construction | 2016 |
| Swinton Hall Management Limited | Households | 1982 |
| Switch Snow Sports Limited | Education | 2012 |
| Switchback Sports Limited | Wholesale & retail | 2008 |
| Switched on Solutions-Energy Ltd | Professional & scientific | 2014 |
| Switchlec Limited | Construction | 2019 |
| Switchstance Limited | Information & communication | 2006 |
| Swizzel Inns Limited | Hospitality | 2025 |
| SWL2TON Ltd | Arts & recreation | 2023 |
| Swms Ltd | Construction | 2024 |
| SWP Properties Ltd | Construction | 2015 |
| SWT Music & Events Ltd | Arts & recreation | 2026 |
| SWU123 Ltd | Administrative & support | 2020 |
| SWX Ltd | Health & social care | 2019 |
| SX Worx CIC | Arts & recreation | 2021 |
| SXB Technology Limited | Information & communication | 2018 |
| Sxndo Ltd | Information & communication | 2026 |
| Sxworx Holdings Limited | Financial services | 2026 |
| SY Automotive Ltd | Other services | 2016 |
| SY Care Training Centre of Excellence Community Interest Company | Other services | 2025 |
| SY Commercial Services Ltd | Administrative & support | 2026 |
| SY Detailing Ltd | Administrative & support | 2024 |
| SY Ecofit CIC | Construction | 2023 |
| SY Events Ltd | Other services | 2019 |
| SY Gorilla Holdings Limited | Financial services | 2025 |
| SY Health Ltd | Health & social care | 2021 |
| SY Healthcare Ltd | Health & social care | 2026 |
| SY Honeycomb Limited | Hospitality | 2025 |
| SY Recovery & Services Limited | Transport & logistics | 2025 |
| SY Securities Ltd | Construction | 2023 |
| Syam Limited | Real estate | 2019 |
| Sycamore Enterprises Limited | Hospitality | 2012 |
| Sycamore Estates (Developments) Ltd. | Construction | 2017 |
| Sycamore Estates Limited | Construction | 2006 |
| Sycamore Gates Ltd | Manufacturing | 2007 |
| Sycamore House Associates Limited | Construction | 2005 |
| Sycamore Sports Limited | Arts & recreation | 2022 |
| SYD Fitness Centre C.I.C. | Health & social care | 2017 |
| SYD Smith (Spares) Limited | Wholesale & retail | 1959 |
| Sydenang Ltd | Wholesale & retail | 2025 |
| Sydor Enterprises Ltd | Wholesale & retail | 2020 |
| Syed Kazmi Ltd | Hospitality | 2020 |
| SYF Holdings Ltd | Real estate | 2025 |
| Syfc Ltd | Real estate | 2022 |
| Syfm Ltd | Construction | 2023 |
| Syha Enterprises Limited | Real estate | 2007 |
| SYK Sales & Shares Ltd | Wholesale & retail | 2025 |
| Sylhet Cinnamon Spice Ltd | Hospitality | 2019 |
| Sylkjewelry Ltd | Wholesale & retail | 2024 |
| Sylmongol Limited | Hospitality | 2024 |
| SYM Consulting Ltd | Professional & scientific | 2020 |
| SYM Ltd | Information & communication | 1996 |
| Symbiotic Learning Limited | Education | 2024 |
| Symmetry Films Ltd | Extraterritorial | 2025 |
| Symmetry Medical Cheltenham Limited | Financial services | 1997 |
| Symon Donovan Properties Limited | Real estate | 2004 |
| Sympill Pharma Ltd | Wholesale & retail | 2023 |
| Symposium Capital Ltd | Extraterritorial | 2018 |
| Syms Facilities Ltd | Construction | 2024 |
| Symteam Facilities Management Limited | Administrative & support | 2016 |
| Synarbor Education Limited | Administrative & support | 1999 |
| Synarbor Limited | Administrative & support | 2004 |
| Synarbor Support Services Limited | Administrative & support | 2005 |
| Syncramix Limited | Real estate | 2020 |