| Smart Properties (York) Ltd | Real estate | 2024 |
| Smart Soma Ltd | Education | 2024 |
| Smart Stable Limited | Agriculture & fishing | 2016 |
| Smart Test Limited | Information & communication | 2025 |
| Smart-Truck Limited | Wholesale & retail | 2023 |
| Smartease Store Ltd | Wholesale & retail | 2025 |
| Smarter Business Processes Limited | Information & communication | 2003 |
| Smartreputation Limited | Real estate | 1999 |
| Smarts of York Limited | Wholesale & retail | 2016 |
| Smartsecurity.Store Ltd | Wholesale & retail | 2017 |
| Smartslice Limited | Professional & scientific | 2014 |
| SMARTWAY2FITNESS Limited | Health & social care | 2014 |
| SMARTWAY2RIDE Limited | Arts & recreation | 2022 |
| Smash Sensation Limited | Hospitality | 2026 |
| Smax Motors Limited | Wholesale & retail | 2011 |
| SMB Sports Limited | Real estate | 2015 |
| Smdh Ltd | Transport & logistics | 2014 |
| Smile Clinic UK Limited | Health & social care | 2009 |
| Smile Kenya Ltd | Other services | 2023 |
| Smiles by Helen Limited | Health & social care | 2025 |
| Smiles by Will Ltd | Health & social care | 2022 |
| Smiley Healthcare Limited | Health & social care | 2015 |
| Smith & Moore Dental Limited | Health & social care | 2025 |
| Smith & Moore Holdings Limited | Financial services | 2025 |
| Smith and SON Property Ltd | Real estate | 2020 |
| Smith Construction Contracts Ltd | Professional & scientific | 2020 |
| Smith Finance Limited | Professional & scientific | 2006 |
| Smith Rhodes Family Butchers and Bakers Limited | Wholesale & retail | 2024 |
| Smith Wilson Holdings Limited | Professional & scientific | 2021 |
| Smith Wilson Limited | Professional & scientific | 2010 |
| Smith Wilson Payroll Bureau Ltd | Professional & scientific | 2023 |
| Smiths Property Management Limited | Households | 2012 |
| Smiths Surveyors Limited | Real estate | 2002 |
| Smithy Brook Letting Limited | Real estate | 2018 |
| Smithy Court Management Company Limited | Real estate | 1992 |
| Smits Pharma Limited | Health & social care | 2010 |
| Smoke Bros Ltd | Hospitality | 2024 |
| Smoke on the Water BBQ N Rock Ltd | Hospitality | 2024 |
| Smoothstorm Limited | Arts & recreation | 1996 |
| Smpbyjosh Limited | Other services | 2026 |
| SMR (York) Limited | Real estate | 2015 |
| SMR Car Parking Limited | Transport & logistics | 2018 |
| Smss Quantity Surveying Limited | Construction | 2013 |
| SMT Accountancy Limited | Professional & scientific | 2004 |
| SMT Commercial Services Ltd | Professional & scientific | 2023 |
| Smudgestone Custom Interiors Ltd | Manufacturing | 2020 |
| Smylett Hall Farms Ltd | Agriculture & fishing | 2022 |
| Smyth Holdings Limited | Real estate | 2019 |
| Snack Heads Ltd | Wholesale & retail | 2024 |
| Snack N DAT Ltd | Hospitality | 2024 |
| Snakesbelly Enterprises Ltd | Manufacturing | 2023 |
| Snaxland Limited | Construction | 2020 |
| Snazzy Brew Ltd | Hospitality | 2024 |
| SNB Holdings (York) Limited | Financial services | 2012 |
| Snetesting Limited | Information & communication | 2025 |
| Snickel Trading Limited | Wholesale & retail | 2020 |
| SNO Production Limited | Financial services | 2025 |
| Snooze FOX Ltd | Real estate | 2026 |
| Snowball Property Ltd | Real estate | 2021 |
| Snowdens Jewellery Workshop Ltd | Wholesale & retail | 2003 |
| Snowdrop Properties (York) Ltd | Real estate | 2023 |
| Snowmass LLP | | 2005 |
| SNS Food and Wines Limited | Wholesale & retail | 2023 |
| SNS Technical Consultant Ltd | Professional & scientific | 2020 |
| Snug Developments (Yorkshire) Limited | Construction | 2023 |
| Snug in the City Ltd | Real estate | 2024 |
| SNW Groundworks Ltd | Construction | 2025 |
| SO Medicolegal Limited | Health & social care | 2019 |
| SO Resources Ltd | Financial services | 2026 |
| SOA Psychotherapy and Counselling Limited | Professional & scientific | 2023 |
| Soabar Sessions Limited | Real estate | 1986 |
| Soap BAG Limited | Wholesale & retail | 2012 |
| Soapysaurus Limited | Wholesale & retail | 2005 |
| Soaring Dragon (UK) Limited | Manufacturing | 1980 |
| Soba UK Developer Ltd | Information & communication | 2021 |
| Sociable Angels Limited | Professional & scientific | 2015 |
| Social ATE Ltd | Financial services | 2021 |
| Social Dining Group Limited | Hospitality | 2021 |
| Social Vision Communications Ltd. | Real estate | 2016 |
| Social Workshop Ltd | Information & communication | 2021 |
| Social York Ltd | Hospitality | 2020 |
| Socialcaddy Ltd | Professional & scientific | 2019 |
| Socialpoint Limited | Professional & scientific | 2020 |
| Society of Ticket Agents and Retailers | Other services | 1997 |
| Sodalite Productions Limited | Information & communication | 2002 |
| Sofalegsonline.Com Ltd | Wholesale & retail | 2018 |
| Sofcore Solutions Ltd | Wholesale & retail | 2026 |
| Softbetix Solutions Limited | Information & communication | 2026 |
| Softlight Digital Services Ltd | Information & communication | 2025 |
| Softlight Imaging Ltd | Information & communication | 2023 |
| SOH Construction Services Ltd | Construction | 2025 |
| Sohum Properties Limited | Real estate | 2019 |
| Soilplan Ltd | Agriculture & fishing | 2023 |
| Sojo Holdings Limited | Hospitality | 2023 |
| Sojourn Escapes Ltd | Hospitality | 2024 |
| Sojourn Lets Limited | Real estate | 2018 |
| Sokalana Consulting Limited | Professional & scientific | 2017 |
| SOL Jonsson Ltd | Professional & scientific | 2025 |
| Solace Medics Ltd | Health & social care | 2023 |
| Solacepathways Ltd | Professional & scientific | 2025 |