| SAX Investments LLP | | 2017 |
| Saxenas Ltd | Health & social care | 2010 |
| Saxlingham Road Limited | Real estate | 2023 |
| Saxons Motor Factors Limited | Other services | 1967 |
| Sayara Group Ltd | Financial services | 2025 |
| Sayon Professional Limited | Other services | 2014 |
| Sazz Investments Ltd | Real estate | 2024 |
| Sazz Redhill Ltd | Real estate | 2024 |
| SB Pharma Ltd | Health & social care | 2012 |
| SB Tech Solutions Limited | Information & communication | 2013 |
| SB3 Designs Ltd | Information & communication | 2013 |
| SBE Timber Products Limited | Manufacturing | 1986 |
| SBL Accountants Limited | Professional & scientific | 2015 |
| Sbrai Limited | Real estate | 2022 |
| SBS Construct Ltd | Extraterritorial | 2024 |
| Sbsp Limited | Wholesale & retail | 2026 |
| SC & C (UK) Limited | Professional & scientific | 2009 |
| SC Consultancy Services Limited | Professional & scientific | 1998 |
| SC Law Solicitors Limited | Professional & scientific | 2009 |
| Scak Holding Ltd | Financial services | 2020 |
| Scak KI Property Ltd | Real estate | 2021 |
| Scalar Capital Ltd | Financial services | 2026 |
| Scalar Group Ltd | Financial services | 2026 |
| Scct Limited | Real estate | 2025 |
| Scenic Holdings Limited | Financial services | 2022 |
| Scheme Support Ltd | Education | 2019 |
| Schiavi Pole Brett Limited | Professional & scientific | 2001 |
| SCM Wings Ltd | Hospitality | 2024 |
| Scoreflow Ltd | Wholesale & retail | 2026 |
| Scorpio 3D Limited | Other services | 2008 |
| Scot Grove (Pinner) Management Company Limited | Households | 1964 |
| Scotia London Properties Ltd | Real estate | 2018 |
| SCR2R Limited | Administrative & support | 2018 |
| Scrummaster Limited | Professional & scientific | 2023 |
| SCS E Learning Ltd | Education | 2021 |
| Sculpt Aesthetica Ltd | Other services | 2018 |
| SD Industries Investments Ltd | Financial services | 2024 |
| SD Smart Designs Ltd | Construction | 2025 |
| SDJ Homes Ltd | Real estate | 2021 |
| SDJ Interiors Ltd | Construction | 2016 |
| Sdnm Group Limited | Professional & scientific | 2020 |
| SE Bicycles Company Limited | Other services | 1993 |
| SE Utilities Ltd | Construction | 2022 |
| Seabee Limited | Extraterritorial | 2018 |
| Sears Morgan Accountancy Limited | Professional & scientific | 2014 |
| Seaside Beacon Properties Ltd | Extraterritorial | 2025 |
| Seaswell Properties Limited | Construction | 2016 |
| Sebastian and Wolf Ltd | Real estate | 2025 |
| Sebbuild Ltd | Manufacturing | 2026 |
| Secretr Media Concept Ltd | Arts & recreation | 2025 |
| Secure Asset Funds Europe Limited | Financial services | 2001 |
| Secure Asset Services LLP | | 2005 |
| Sedge Consulting Limited | Information & communication | 2023 |
| SEE Space Consulting Ltd | Professional & scientific | 2019 |
| SEE Space Limited | Real estate | 2016 |
| Seeders Foundation Ltd | Education | 2012 |
| Seferi Properties Ltd | Real estate | 2023 |
| Sehem Ltd | Professional & scientific | 2019 |
| Sehgal Investments Limited | Real estate | 2022 |
| Sehj Khanna Investment Ltd | Real estate | 2025 |
| Sekai Limited | Wholesale & retail | 2021 |
| Select Performance and Prestige Ltd | Wholesale & retail | 2019 |
| Selectadisc Limited | Extraterritorial | 2009 |
| SELVA69 Ltd | Real estate | 2026 |
| Selvanathan Consulting Ltd | Professional & scientific | 2025 |
| Selvanathan Property Holdings Limited | Real estate | 2021 |
| SEM Education Centre Limited | Education | 2019 |
| Seneca SCS Ltd | Real estate | 2024 |
| Sensory Edge Limited | Wholesale & retail | 2021 |
| Sentient Tax Ltd | Professional & scientific | 2024 |
| Senzur Limited | Real estate | 2019 |
| SEP Insights Ltd | Professional & scientific | 2025 |
| SEQ1 Ltd | Other services | 2019 |
| Sequoia CH Group Ltd | Other services | 2018 |
| Sequoia Management Limited | Real estate | 2022 |
| Sequoia Solutions Group Limited | Wholesale & retail | 2024 |
| Serafina Ltd | Professional & scientific | 2019 |
| Serenara Ltd | Health & social care | 2025 |
| Serene View Properties Ltd | Real estate | 2021 |
| Services R US Ltd | Construction | 2013 |
| SET DEC Drapes Ltd | Information & communication | 2012 |
| Setfield Limited | Wholesale & retail | 2016 |
| Sethi Optics Limited | Wholesale & retail | 2004 |
| Seven & Seven Construction Ltd | Construction | 2023 |
| Seven Project Management Ltd | Information & communication | 2021 |
| Sewardstone Holdings Limited | Construction | 2018 |
| Sexton Family Holdings Limited | Financial services | 2024 |
| SF Pharma Ltd | Wholesale & retail | 2026 |
| SG Digital Marketing Ltd | Wholesale & retail | 2015 |
| SGF Group Limited | Wholesale & retail | 2018 |
| SH Civils and Fibre Consultancy Limited | Professional & scientific | 2026 |
| SH Pinnacle Consultancy Limited | Professional & scientific | 2025 |
| SHA SHA Limited | Construction | 2011 |
| Shaan (Homes) Ltd | Real estate | 2020 |
| Shacky Productions Limited | Arts & recreation | 2024 |
| Shadowfax International Ltd | Wholesale & retail | 2003 |
| Shah Designs Ltd | Professional & scientific | 2013 |
| Shah Home Physiotherapist Ltd | Health & social care | 2022 |
| Shah Pharmacy Limited | Wholesale & retail | 2011 |
| Shah Surveyors Limited | Construction | 2021 |