| Summer Santa Ltd | Transport & logistics | 2017 |
| Summerdown Properties Ltd | Real estate | 2025 |
| Summerfield Management Consultants Ltd | Information & communication | 2018 |
| Summerhouse Healthcare Limited | Health & social care | 2020 |
| Summerhouse Place Management Company Limited | Real estate | 2009 |
| Summersfield (Papworth) Management Company Limited | Households | 2011 |
| Summertime Leisure Limited | Arts & recreation | 1994 |
| Summit Commercial Services Ltd | Administrative & support | 2026 |
| Summit Education Ltd | Education | 2025 |
| Summit Shine Cleaning Ltd | Administrative & support | 2024 |
| SUMMIT7 Business Coaching Ltd | Administrative & support | 2021 |
| Summitstone Developments Ltd | Real estate | 2025 |
| Sun Green Ltd | Wholesale & retail | 2025 |
| Sun of the Woods Ltd | Agriculture & fishing | 2026 |
| Sunbal UK Limited | Manufacturing | 2023 |
| Sunbeds by Anna Ltd | Health & social care | 2026 |
| Suncare Limited | Health & social care | 2015 |
| Suncatcher Foods Ltd | Wholesale & retail | 2009 |
| SUNCITY19 Beauty Limited | Other services | 2009 |
| SUNCITY19 Nails Limited | Other services | 2009 |
| SUNCITY19 Tanning Limited | Other services | 2009 |
| Suncredit Energy Limited | Energy | 2013 |
| Suncredit Solutions Limited | Energy | 2013 |
| Sunday Best Ltd. | Wholesale & retail | 1995 |
| Sunderland Commercial Properties Ltd | Real estate | 2022 |
| Sundial Homes Limited | Real estate | 2019 |
| Sundial Planning Limited | Professional & scientific | 2012 |
| Sundon Autos Limited | Wholesale & retail | 2022 |
| Sunflower Pubs Ltd | Hospitality | 2026 |
| Sunflower Support Ltd | Health & social care | 2019 |
| Sunil DAS Data Communications Ltd | Information & communication | 2009 |
| Sunisa Elliott Limited | Health & social care | 2026 |
| Sunmai Trading Ltd | Wholesale & retail | 2024 |
| Sunmast Limited | Real estate | 1999 |
| Sunny HOO KEE Limited | Hospitality | 2021 |
| Sunny Socks Nursery Schools Limited | Education | 2004 |
| Sunny Traders Limited | Transport & logistics | 2005 |
| Sunraf Trans Ltd | Transport & logistics | 2017 |
| Sunset Corporation Limited | Other services | 1999 |
| Sunshine Farm Paddocks Ltd | Real estate | 2017 |
| Sunshine Grey Pictures Limited | Information & communication | 2024 |
| Sunshine Overseas Ltd | Wholesale & retail | 2024 |
| Sunshine Property Group Limited | Real estate | 2017 |
| Super Brokers Ltd | Financial services | 2019 |
| Super Heating Ltd | Construction | 2021 |
| Super Sausage Car Wash Ltd | Other services | 2020 |
| Super Shawarma Ltd | Hospitality | 2026 |
| Super Smile Ltd | Health & social care | 2013 |
| Super Toons Ltd | Wholesale & retail | 2021 |
| Supercapital Ltd | Financial services | 2001 |
| Supercars Northampton Limited | Transport & logistics | 2015 |
| Supercool East Ltd | Construction | 2017 |
| Supercool Group Limited | Construction | 2018 |
| Supercool Holdings Limited | Financial services | 2025 |
| Supercool North Ltd | Construction | 2017 |
| Supercool Refrigeration and Air Conditioning Limited | Construction | 2009 |
| Supercool South Ltd | Construction | 2017 |
| Supercool West Ltd | Construction | 2017 |
| Superior Filter Products Ltd | Wholesale & retail | 1989 |
| Superior Living Properties Limited | Real estate | 2017 |
| Superiorevchargingsolutions Ltd | Construction | 2020 |
| Supermarket Northampton Ltd | Wholesale & retail | 2026 |
| Supershine Valeting Services | | 1993 |
| Supplio Ltd | Wholesale & retail | 2026 |
| Supply Chain Compliance Limited | Professional & scientific | 2013 |
| SUPPLY2VAPE Ltd | Wholesale & retail | 2017 |
| Supplyant Ltd | Information & communication | 2014 |
| Support & Match CIC | Health & social care | 2020 |
| Support 4 Independence Limited | Health & social care | 2009 |
| Support and Training in Prep, Primary and Senior Schools Limited | Education | 1966 |
| Supported Living Housing CIC | Real estate | 2023 |
| Supported Living Properties Ltd | Real estate | 2021 |
| Supported Living Services (Northampton) Ltd | Health & social care | 2018 |
| Supportive Health Ltd | Health & social care | 2021 |
| Supportive Work Solutions Ltd | Administrative & support | 2022 |
| Supportmatch Homeshare Limited | Professional & scientific | 2017 |
| Supports Direct Limited | Wholesale & retail | 2012 |
| Supreme Corp Limited | Manufacturing | 2024 |
| Supreme Delivery Service Ltd | Wholesale & retail | 2019 |
| Supreme Health Group Limited | Health & social care | 2023 |
| Supreme Property Lets Ltd | Real estate | 2020 |
| Supro Investments Limited | Real estate | 2020 |
| Supro Limited | Health & social care | 2014 |
| Suproperty Management & Maintenance Limited | Real estate | 2019 |
| Suraj Transport Limited | Transport & logistics | 2022 |
| Surecity Networks (UK) Ltd | Information & communication | 2022 |
| Sureflo Plumbing & Heating Limited | Construction | 2019 |
| Sureflow Services Northampton Ltd | Manufacturing | 2010 |
| Surfline Care Services Ltd | Health & social care | 2024 |
| Surman Weston Limited | Professional & scientific | 2012 |
| Suros Technology Ltd | Information & communication | 2024 |
| Surrey Blinds Limited | Wholesale & retail | 2013 |
| Surrey Group Ltd | Hospitality | 2022 |
| Surtur Fire Limited | Other services | 2022 |
| Suryaya Enterprise UK Limited | Wholesale & retail | 2014 |
| Susan Briggs Limited | Other services | 2021 |
| Sushel Ohri Associates Limited | Other services | 2003 |
| Sushi Home Limited | Hospitality | 2020 |
| Sustain Recycling Ltd | Water & waste | 2021 |
| Sustainable Electrical Development Solutions Ltd | Construction | 2018 |