| Serenity Springs Ltd | Health & social care | 2023 |
| Serenity Street Properties Ltd | Real estate | 2026 |
| Serenity Wellness Collective Limited | Health & social care | 2026 |
| Serenova Nutrition Limited | Wholesale & retail | 2024 |
| Serginter Construct Limited | Construction | 2018 |
| Service & Support Ltd | Other services | 2009 |
| Seven Bespoke Joinery Ltd | Construction | 2024 |
| Sevenstreams Ltd | Wholesale & retail | 2025 |
| Sexton Maintenance Limited | Administrative & support | 2011 |
| SF Blue Properties Ltd | Real estate | 2022 |
| SF Spedition Ltd | Transport & logistics | 2025 |
| Sgbsyp Limited | Wholesale & retail | 2012 |
| SGS 68 Limited | Real estate | 2020 |
| SH Agroconnect Consulting Ltd | Professional & scientific | 2024 |
| Shade Umbra Limited | Wholesale & retail | 2023 |
| Shadow 2020 Ltd | Hospitality | 2020 |
| Shake N Slush Limited | Wholesale & retail | 2017 |
| Shalamanov Limited | Transport & logistics | 2016 |
| Shannon Thompson Permanent Make UP Ltd | Other services | 2024 |
| Sharing the Kindness CIC | Health & social care | 2026 |
| Shaufert Ltd | Construction | 2026 |
| Shaun Lewis Ltd | Construction | 2025 |
| Shauna-Leigh Property Limited | Administrative & support | 2023 |
| Shaw Mechatronics Ltd. | Professional & scientific | 2022 |
| Sheer Innovations Limited | Wholesale & retail | 2006 |
| Shefford Osteopathic Clinic Limited | Health & social care | 2023 |
| Shephard & Sons Engineering Ltd | Professional & scientific | 2020 |
| Sheridan Thompson Consulting Limited | Information & communication | 2026 |
| SHG Trading Limited | Transport & logistics | 2021 |
| Shining Star Properties Ltd | Real estate | 2022 |
| Ship Nest Ltd | Transport & logistics | 2024 |
| Shiv Convenience Store Limited | Wholesale & retail | 2022 |
| Shokri Group Co. Ltd | Real estate | 2025 |
| Shokwave Ltd | Professional & scientific | 2024 |
| Shopafrik Ltd | Wholesale & retail | 2023 |
| Shout Marketing Limited | Professional & scientific | 2008 |
| Shree Home Improvements Ltd | Construction | 2021 |
| SI Leisure Ltd | Hospitality | 2024 |
| Siana Trans Ltd | Transport & logistics | 2022 |
| SIB Energy Limited | Manufacturing | 2013 |
| Side Housing Limited | Construction | 2018 |
| Siegfried Asset Management Limited | Financial services | 2022 |
| Signature Prep & Restoration Ltd | Information & communication | 2024 |
| Signature Vehicle Storage Ltd | Information & communication | 2020 |
| Signet Consulting Limited | Information & communication | 2011 |
| Signet Fusion Services Limited | Health & social care | 2023 |
| Signet Property Limited | Real estate | 2017 |
| Silavati Property Management Limited | Real estate | 2026 |
| Silentpride Limited | Construction | 2006 |
| Siles Group Limited | Wholesale & retail | 2026 |
| Sillyfish Software Engineering Limited | Information & communication | 2024 |
| Silsila Dining Ltd | Hospitality | 2020 |
| Silverbow Living Ltd | Professional & scientific | 2022 |
| Silverleaf Studios Limited | Wholesale & retail | 2025 |
| Silviu Transport Ltd | Transport & logistics | 2018 |
| Silvro Ltd | Financial services | 2020 |
| SIM Racing Consultants Limited | Professional & scientific | 2025 |
| Simba Auto Ltd | Wholesale & retail | 2025 |
| Simi Medical Limited | Health & social care | 2025 |
| Simms Group Ltd | Real estate | 2022 |
| Simms Roofing & Cladding Limited | Construction | 2015 |
| Simon Jeffs Limited | Construction | 2011 |
| Simplebooks Advisory Ltd | Professional & scientific | 2026 |
| Simpliphy Ltd | Professional & scientific | 2020 |
| Simply Consulting, Simply Limited | Professional & scientific | 2016 |
| Simpson West Estate Agents Limited | Real estate | 2018 |
| Simpson West Lettings Limited | Real estate | 2018 |
| Simputers Limited | Information & communication | 2021 |
| SIN Cargo Ltd | Transport & logistics | 2026 |
| Sincerely Devoted to YOU Limited | Wholesale & retail | 2025 |
| Sinclair Engineering Solutions Ltd | Manufacturing | 2019 |
| Singlehurst Events Management Ltd | Professional & scientific | 2024 |
| Sinless Silk Ltd | Extraterritorial | 2022 |
| Sirah Consultancy Limited | Information & communication | 2024 |
| Sirhowy Valley Foods Limited | Manufacturing | 1999 |
| Sixth Sense Enterprise Ltd | Information & communication | 2025 |
| Sizabantu Community Projects CIC | Health & social care | 2024 |
| SJ Dickson Ltd | Education | 2018 |
| SJA Mortgages Ltd | Financial services | 2019 |
| SJT Consultancy Services Limited | Professional & scientific | 2020 |
| SJW Cars Ltd | Wholesale & retail | 2024 |
| Skew Consulting Ltd | Professional & scientific | 2022 |
| Skewis Design & Build Ltd | Information & communication | 2018 |
| SKJ Groundworks Ltd | Construction | 2016 |
| SKT Auto Ltd | Wholesale & retail | 2016 |
| Sky Cabs Corby Limited | Transport & logistics | 2001 |
| Sky Direct Care Services Ltd | Health & social care | 2022 |
| Sky Solutions Holding Ltd | Information & communication | 2026 |
| Skye Equipment Co Limited | Manufacturing | 1985 |
| Sleipnir Creations CIC | Education | 2023 |
| Slice of Pleasure Limited | Manufacturing | 2023 |
| SLR Sorting Ltd | Manufacturing | 2017 |
| SM Embroidery Limited | Wholesale & retail | 2013 |
| Small Business Payroll Service Limited | Administrative & support | 1999 |
| Smart ABC Ltd | Extraterritorial | 2015 |
| Smart Build Property Developments Limited | Construction | 2015 |
| Smart Build Services and Development Limited | Construction | 2012 |
| Smart Business Assistance Ltd | Administrative & support | 2019 |
| Smart Detailing Ltd | Wholesale & retail | 2023 |
| Smart Ledger Consultancy Ltd | Professional & scientific | 2025 |