| Sigma Marine Limited | Other services | 1992 |
| Silverseas Limited | Wholesale & retail | 1985 |
| Sitara Limited | Wholesale & retail | 1996 |
| Skup Holdings Limited | Real estate | 1991 |
| Skystyle Limited | | 1984 |
| Sloggetts (Contractors) | | 1937 |
| SON Trimmings (UK) Limited | Wholesale & retail | 2001 |
| SON Trimmings Limited | Wholesale & retail | 1996 |
| Sovereign Print Services Limited | | 1988 |
| Sphinx UK Ltd | Professional & scientific | 2003 |
| Spinvest UK Properties Limited | Real estate | 2015 |
| SR Independent Financial Centre Limited | Extraterritorial | 2005 |
| Sskv Ltd | Professional & scientific | 2022 |
| St.Helen's School Northwood | Education | 1946 |
| Stan Matthews Design Studio Limited | Wholesale & retail | 2010 |
| Stelly Building Solutions Ltd | Construction | 2014 |
| Stonerock Design Limited | Administrative & support | 2007 |
| Style Publicity Limited | Professional & scientific | 1978 |
| Summit Aerial Installations Limited | Construction | 2008 |
| Suricare Limited | Administrative & support | 1986 |
| Suve & Co Limited | Other services | 2003 |
| Taneja Properties Ltd | Real estate | 2025 |
| Technical Video Services Limited | | 1981 |
| Tenk Products Limited | | 1961 |
| TEO Decorators Ltd | Construction | 2019 |
| Teopak Ltd | Hospitality | 2024 |
| Term Developments Limited | Professional & scientific | 2014 |
| Thames Valley Medical Limited | Health & social care | 2003 |
| THE Cock Inn (Luddesdown) Limited | Hospitality | 2006 |
| THE Earth Agency Limited | Hospitality | 2014 |
| THE Luncharian Limited | Hospitality | 2006 |
| THE Original Polythene Tiger Co. Ltd. | | 1988 |
| THE Warwick Clinic Ltd | Health & social care | 2005 |
| Times Internet (UK) Ltd | Information & communication | 2007 |
| Tony Stunt Creative Services Limited | Professional & scientific | 2013 |
| Top-Op (Foods) Limited | Wholesale & retail | 1976 |
| Topstraits Limited | | 1972 |
| TPF Properties Ltd | Real estate | 2007 |
| Trend Speaker Services Limited | Information & communication | 2013 |
| Trustax Limited | Professional & scientific | 2006 |
| Trusted Square Limited | Administrative & support | 2024 |
| Tuck-In Restaurants Limited | Real estate | 2002 |
| Twickenham Plating Group Limited | Manufacturing | 1947 |
| Twickenham Plating Limited | Manufacturing | 1949 |
| Twickenham Plating Trustees Limited | Professional & scientific | 1999 |
| Vailankanni Estate Ltd | Real estate | 2025 |
| Valito Secretarial Limited | Professional & scientific | 1973 |
| Valy Construction & Refurb Ltd | Administrative & support | 2017 |
| Varnstan Services Limited | | 1981 |
| Victor Salmon Limited | Real estate | 1979 |
| Victoria Building Solutions Ltd | Construction | 2024 |
| VN Dermatology Ltd | Health & social care | 2022 |
| W. & B. Lancaster Limited | | 1979 |
| Well Hall Limited | Professional & scientific | 2015 |
| Wembley Motor Auctions Limited | Professional & scientific | 1990 |
| Westend Bargains Limited | Wholesale & retail | 1985 |
| Wing Construction Limited | Construction | 1987 |
| World of Wireless Homes Limited | Other services | 2005 |
| Yellow Mountain Property Ltd | Real estate | 2006 |