| SVK Healthcare Limited | Health & social care | 2022 |
| SW Electrical Engineering Limited | Construction | 2023 |
| Swain Estate Management Limited | Real estate | 2014 |
| Swakeleys House Ickenham Ltd | Real estate | 2020 |
| Swallow Barn Limited | Professional & scientific | 2007 |
| Swallow Catering Ltd | Hospitality | 2018 |
| Swan Commercial Finance Limited | Financial services | 2018 |
| Swan House Limited | Extraterritorial | 2011 |
| Swan Park (Dawlish) Management Company Limited | Households | 2021 |
| Swanston Property (Harrogate) Limited | Households | 1982 |
| SWC Components Ltd | Wholesale & retail | 2025 |
| Sweet Adore Limited | Hospitality | 2021 |
| Sweet and Seasonal Ltd | Wholesale & retail | 2022 |
| Sweet Choice York Ltd | Wholesale & retail | 2024 |
| Sweet Cures Limited | Wholesale & retail | 2020 |
| Sweet P Catering Limited | Hospitality | 2016 |
| Sweet Treats by MIL Ltd | Wholesale & retail | 2021 |
| Sweg Management Ltd | Professional & scientific | 2025 |
| Swell Dwellings Limited | Administrative & support | 2017 |
| Swift Analytical Limited | Professional & scientific | 2011 |
| Swift Apartments Limited | Real estate | 2024 |
| Swift AV Solutions Ltd | Information & communication | 2020 |
| Swift Fitness (York) Limited | Arts & recreation | 2006 |
| Swiftcookson Holdings Ltd | Financial services | 2022 |
| Swiftrun (GMS) Consulting Ltd | Professional & scientific | 2012 |
| Swifts Contracts Limited | Professional & scientific | 2023 |
| Swine & Vine Ltd | Wholesale & retail | 2025 |
| Swinton Motors Limited | Wholesale & retail | 1998 |
| Swinton Project Solutions Ltd | Professional & scientific | 2012 |
| Swirl Baits Ltd | Wholesale & retail | 2020 |
| Swirlz Gelato Limited | Hospitality | 2018 |
| Switch Workplace Interiors Limited | Professional & scientific | 2024 |
| SWS Air Conditioning Ltd | Construction | 2020 |
| SY Real Estate Solutions Ltd | Real estate | 2025 |
| SY Solutions Ltd | Information & communication | 2006 |
| SYC123 Ltd | Real estate | 2024 |
| SYC456 Ltd | Real estate | 2024 |
| Sycamore Rise (Thame) Residents Management Company Limited | Households | 2016 |
| Syedpur Lounge Limited | Hospitality | 2020 |
| Syenyx Limited | Information & communication | 2008 |
| Sykes International Trading Limited | Wholesale & retail | 1997 |
| Sylatech Limited | Manufacturing | 2014 |
| Sylec Ltd | Construction | 2022 |
| Sylvankin Ltd | Education | 2022 |
| Symon Lord Productions Ltd | Information & communication | 2011 |
| Symphony Live Ltd | Arts & recreation | 2026 |
| Synanetics Ltd | Information & communication | 2015 |
| Synergy at Home Cleaning Ltd | Administrative & support | 2013 |
| Synergy Cleaning Limited | Administrative & support | 2009 |
| Synergy Integrated Services Ltd | Construction | 2012 |
| Synergy Language Services Limited | Administrative & support | 2009 |
| Synergy Partnerships Limited | Professional & scientific | 2024 |
| Synergy Petcare Ltd | Professional & scientific | 2025 |
| Synergy Property (York) Limited | Real estate | 2017 |
| Sypos In-Store Solutions Limited | Manufacturing | 2017 |
| System Plate Manufacture Limited | Manufacturing | 2016 |
| Systemised.Io Ltd | Information & communication | 2026 |
| Systems Online Limited | Information & communication | 1996 |
| SYSTEMS4FOOD Ltd | Professional & scientific | 2022 |
| Systmuk Limited | Information & communication | 2015 |
| Szechuan York Ltd | Hospitality | 2024 |
| Sériyoux Ltd | Information & communication | 2025 |
| T & R Holdich Limited | Administrative & support | 2013 |
| T & S LEE Limited | Agriculture & fishing | 2023 |
| T & S Taverns Holdings Limited | Financial services | 2024 |
| T & T Trading Ltd | Real estate | 2023 |
| T & T.A. Park (Transport) Limited | Transport & logistics | 2004 |
| T and T.A. Park Limited | Agriculture & fishing | 1965 |
| T C & G I Foster (Antiques) Ltd | Wholesale & retail | 2002 |
| T C Remarkables Ltd | Wholesale & retail | 2022 |
| T E Davies Limited | Wholesale & retail | 2018 |
| T F Daniells Limited | Administrative & support | 2002 |
| T J Atkin Ltd | Construction | 2013 |
| T J Mudd & Co Consultant Surveyors Limited | Real estate | 2014 |
| T Kama Consultancy Ltd | Information & communication | 2023 |
| T Lakin Ltd | Hospitality | 2022 |
| T M Bylo Ltd | Construction | 2020 |
| T M Chemicals Limited | Manufacturing | 2018 |
| T Mitchell Contracting Ltd | Agriculture & fishing | 2025 |
| T P Delivery Ltd | Professional & scientific | 2011 |
| T P Jordeson & Company Limited | Wholesale & retail | 1989 |
| T P Jordeson (Holdings) Limited | Professional & scientific | 2012 |
| T Peart Joinery Ltd | Construction | 2003 |
| T Projects Ltd | Construction | 2021 |
| T S Hartley & Sons Limited | Wholesale & retail | 1989 |
| T Soanes & SON (Potatoes) Ltd | Agriculture & fishing | 2003 |
| T Squared Electrical Ltd | Construction | 2026 |
| T Wilcock Plumbing & Heating Ltd | Construction | 2019 |
| T Wood Services Ltd | Manufacturing | 2022 |
| T&J York Limited | Other services | 2010 |
| T&S Taverns Limited | Hospitality | 2020 |
| T&T the Old York Ltd | Hospitality | 2024 |
| T'Bridge Cafe Ltd | Financial services | 2018 |
| T. W. Fields (Osbaldwick) Limited | Construction | 2013 |
| T.B.Bratley & SON Limited | Agriculture & fishing | 1964 |
| T.Creative Holdings Limited | Financial services | 2025 |
| T.D.E. Pick & Sons Limited | Agriculture & fishing | 2016 |
| T.D.York Ltd | Wholesale & retail | 2023 |
| T.E. Almond (Farms) Limited | Agriculture & fishing | 1978 |
| T.E.L Concierge Ltd | Other services | 2020 |