| Stanwick Properties Limited | Real estate | 1984 |
| Staples Real Estate Ltd | Real estate | 2024 |
| Star Collectibles Ltd | Wholesale & retail | 2024 |
| Star Equity Ltd | Wholesale & retail | 2019 |
| Starco TV 4 Limited | Information & communication | 2021 |
| Starfish Commercial Ltd | Professional & scientific | 2011 |
| Stark Brickwork Group Ltd | Construction | 2022 |
| Starla Developments Ltd | Construction | 2020 |
| Starmagic Games Ltd | Information & communication | 2025 |
| Starmeduk Limited | Manufacturing | 2014 |
| Stars&Sweets Candy Ltd | Wholesale & retail | 2024 |
| Starseed Properties Limited | Real estate | 2025 |
| Starstorm Group Ltd. | Information & communication | 2019 |
| Startboost Limited | Real estate | 1999 |
| Starting OFF Limited | Administrative & support | 1999 |
| Startrend Limited | Wholesale & retail | 1995 |
| Startright Nursery Limited | Education | 2000 |
| Station Management Company Limited | Households | 2011 |
| Station Mill Antiques Centre Limited | Wholesale & retail | 2010 |
| Station Road Felsted Residents Management Company Limited | Real estate | 2023 |
| Station Taxis (Kings Lynn) Limited | Wholesale & retail | 2002 |
| Station Taxis Northampton Trading AS Station Taxis Milton Keynes Limited | Transport & logistics | 2020 |
| Statom Renovations Ltd | Construction | 2023 |
| Staverton Park Developments Limited | Construction | 2026 |
| Staverton Park Estate Limited | Wholesale & retail | 2018 |
| Staverton Park Group Ltd | Real estate | 2025 |
| Stavros Cleaning Ltd | Administrative & support | 2025 |
| Staying Happy Limited | Construction | 2022 |
| Staysure.Co.Uk Limited | Financial services | 2004 |
| STC Tiles and Bathrooms Limited | Wholesale & retail | 2019 |
| STD Trans UK Ltd | Transport & logistics | 2019 |
| STE Scaffold Services Ltd | Construction | 2024 |
| Steadfast Roofing Merchants Limited | Wholesale & retail | 1998 |
| Steamfittings Ltd | Manufacturing | 2024 |
| Steamngo Limited | Wholesale & retail | 2020 |
| Steaua Domnului Limited | Wholesale & retail | 2025 |
| Steben Consulting Limited | Professional & scientific | 2013 |
| Steel City Ltd | Manufacturing | 2016 |
| Steel Construction Limited | Manufacturing | 1995 |
| Steel Horse Clinic Ltd | Construction | 2014 |
| Steel Security Systems Ltd | Administrative & support | 2018 |
| Steel Services Co Limited | Construction | 2002 |
| Steel Solutions Limited | Manufacturing | 2001 |
| Steelbacks Foundation | Health & social care | 2022 |
| Steele Estate Limited | Real estate | 2024 |
| Steele Estates & Developments Limited | Real estate | 2019 |
| Steele Vehicle Movements Ltd | Transport & logistics | 2023 |
| Steele's Plumbing & Heating Ltd | Construction | 2020 |
| Steepletone Products Limited | Wholesale & retail | 1972 |
| Stef-Demolition Ltd | Construction | 2025 |
| Stefan Munteanu Ltd | Construction | 2025 |
| Stefan Rashev Limited | Professional & scientific | 2012 |
| Stefanie Ltd | Education | 2019 |
| Stefanspanu Ltd | Transport & logistics | 2026 |
| Stefany Ltd | Health & social care | 2018 |
| Steffan the Jeweller Limited | Wholesale & retail | 1976 |
| Stefyuk Ltd | Transport & logistics | 2014 |
| Stela-Martin Properties Limited | Real estate | 2006 |
| Stelina Cleaning Ltd | Administrative & support | 2024 |
| Stellar Business Finance Limited | Financial services | 2024 |
| Stellar Event Hire Ltd | Administrative & support | 2021 |
| Stellar Northampton Ltd | Construction | 2025 |
| Stellar Represents Ltd | Professional & scientific | 2022 |
| Stema Properties Ltd | Real estate | 2013 |
| Stena Properties Limited | Real estate | 2024 |
| Step Ahead Global Foods Distribution Limited | Wholesale & retail | 2025 |
| Step by Step Dance Promotions Limited | Arts & recreation | 2014 |
| Step by Step Dance School Limited | Arts & recreation | 2014 |
| Step Forward With Lewis CIC | Other services | 2024 |
| Step Stone Logistics Ltd | Transport & logistics | 2017 |
| Stepfamily Assess Ltd | Health & social care | 2009 |
| Steph Logistics Limited | Transport & logistics | 2014 |
| Stephen Atkin Ltd | Manufacturing | 2014 |
| Stephen Collier Ltd | Information & communication | 2023 |
| Stephen Freestone Ltd | Administrative & support | 2014 |
| Stephen Myler Limited | Arts & recreation | 2013 |
| Stephen Necker Developments Limited | Construction | 2013 |
| Stephen Thomas Robinson Ltd | Extraterritorial | 2025 |
| Stephensons Online Limited | Wholesale & retail | 2012 |
| Stepping Stones Associates Limited | Real estate | 2008 |
| Stepping Stones Care Homes (Oakfield House) Limited | Extraterritorial | 2012 |
| Stepping Stones Care Homes (Phoenix House) Limited | Extraterritorial | 2012 |
| Stepping Stones Logistics Ltd | Transport & logistics | 2017 |
| Stepping Stones Northampton Ltd | Financial services | 2015 |
| Stepping UP Productions Ltd | Information & communication | 2023 |
| Steppn- Stone Limited | Hospitality | 2015 |
| Stepwise Careers Ltd | Information & communication | 2018 |
| Stereo DT Ltd | Hospitality | 2022 |
| Stericsson Drilling Limited | Manufacturing | 2014 |
| Steriflow Limited | Manufacturing | 2011 |
| Sterivac Limited | Manufacturing | 1997 |
| Sterling Brand Partners Ltd | Wholesale & retail | 2026 |
| Sterling Outreach Limited | Professional & scientific | 2025 |
| Sterling Plastics Limited | Manufacturing | 2022 |
| Sterling Satellite Installations Ltd | Information & communication | 2016 |
| Sterling Scaffolding ( Northampton) Ltd | Construction | 2004 |
| Sterling Starz Ltd | Wholesale & retail | 2026 |
| Stertil UK Ltd. | Manufacturing | 1973 |
| Steve Barry Enterprises Limited | Professional & scientific | 2020 |
| Steve Curtis Consulting Limited | Professional & scientific | 2012 |