| Rocksure 5 Kingham Ltd | Construction | 2025 |
| Rocksure Construction Ltd | Construction | 2025 |
| Rocksure Holdings Ltd | Financial services | 2025 |
| Rodeax Ltd. | Information & communication | 2015 |
| Rollright Spring Sanctuary Limited | Hospitality | 2025 |
| Ropsley Quarry Limited | Extraterritorial | 2009 |
| ROS Richardson Consulting Ltd | Professional & scientific | 2011 |
| Rosetta Life | Arts & recreation | 1999 |
| Rosewell Engineering Ltd | Professional & scientific | 2023 |
| Ross & Ross Bespoke Ltd | Hospitality | 2023 |
| Ross & Ross Food Ltd | Hospitality | 2011 |
| ROX Global Ltd | Administrative & support | 2024 |
| Royal Oak Ramsden Limited | Hospitality | 2019 |
| Royden Corp Limited | Professional & scientific | 2019 |
| RT Investment Properties Ltd | Real estate | 2023 |
| Run Wilde Ltd | Wholesale & retail | 2016 |
| S a D Light Box Co Limited | Extraterritorial | 1994 |
| S and P Carpentry Ltd | Construction | 2016 |
| S G Harris Groundworks Limited | Construction | 2007 |
| S J Pedley Construction Ltd | Construction | 2014 |
| S. B. Allen Limited | Construction | 2006 |
| S.Peet Groundworks Limited | Construction | 2017 |
| S.R. Moss Builders Limited | Construction | 2014 |
| Saltpig Curing Company Ltd. | Manufacturing | 2016 |
| Samboras Tanning and Beauty Ltd | Other services | 2025 |
| Sand & Stone Escapes Ltd | Administrative & support | 2016 |
| Sandbox Bioscience Ltd | Professional & scientific | 2024 |
| Sandford Mount Development Co. Limited | Real estate | 1960 |
| Sandford Press Limited | Information & communication | 2014 |
| Sandton Limited | Administrative & support | 2020 |
| Sanglaise Brokers Ltd | Transport & logistics | 2026 |
| Sanplex Limited | Wholesale & retail | 2016 |
| Sapienter SI Sincere Ltd | Wholesale & retail | 2020 |
| Sasnick Holdings Limited | Financial services | 2024 |
| Savatar Limited | Extraterritorial | 2023 |
| Scaffolded Limited | Real estate | 2018 |
| Scaremongering Limited | Professional & scientific | 2011 |
| SCIENCE2MARKET Ltd | Agriculture & fishing | 2018 |
| Scissors&Creed Limited | Other services | 2026 |
| Scribe Services Ltd. | Information & communication | 2018 |
| SDG Business Solutions Ltd | Professional & scientific | 2022 |
| Seadev Ltd | Information & communication | 2023 |
| Season Beds Ltd | Administrative & support | 2011 |
| Seasonsim Ltd | Information & communication | 2026 |
| Seedbed Theatre Ltd | Education | 2015 |
| Sensational Homes Ltd | Construction | 2026 |
| September Properties Limited | Construction | 2006 |
| SET and Social Limited | Professional & scientific | 2024 |
| Severn Trent Green Power (Andigestion) Limited | Manufacturing | 1984 |
| Severn Trent Green Power (Bridgend) Limited | Energy | 2015 |
| Severn Trent Green Power (Cassington) Limited | Energy | 2008 |
| Severn Trent Green Power (CW) Limited | Water & waste | 2012 |
| Severn Trent Green Power (Hertfordshire) Limited | Water & waste | 2008 |
| Severn Trent Green Power (North London) Limited | Energy | 2015 |
| Severn Trent Green Power (Rbwm) Limited | Water & waste | 2010 |
| Severn Trent Green Power (Wallingford) Limited | Energy | 2011 |
| Severn Trent Green Power (West London) Limited | Energy | 2012 |
| Severn Trent Green Power Atherstone Limited | Energy | 2020 |
| Severn Trent Green Power Biogas Limited | Energy | 2008 |
| Severn Trent Green Power Cayton Limited | Energy | 2019 |
| Severn Trent Green Power Church Farm Limited | Energy | 2021 |
| Severn Trent Green Power Composting Limited | Water & waste | 2003 |
| Severn Trent Green Power Group Limited | Professional & scientific | 2009 |
| Severn Trent Green Power Holdings Limited | Financial services | 2015 |
| Severn Trent Green Power Limited | Energy | 2002 |
| Severn Trent Green Power Lodge Farm Limited | Energy | 2020 |
| Severn Trent Wind Power Limited | Energy | 2011 |
| SG Energy Ltd | Professional & scientific | 2021 |
| SH Homes (Holdings) Ltd | Construction | 2004 |
| Shadowfield Limited | Construction | 2014 |
| Shecounts Accountancy Ltd | Professional & scientific | 2025 |
| Shield Woodworking Limited | Construction | 1984 |
| Shilson's Place Ltd | Households | 2000 |
| Shipton Design Ltd | Construction | 2009 |
| Shipton-Under-Wychwood Wild Garden and Woods | Arts & recreation | 2009 |
| Shutter Inspired Ltd | Administrative & support | 2022 |
| Siceo Limited | Professional & scientific | 2004 |
| Sika Instruments Limited | Wholesale & retail | 2015 |
| Silvasheep Cymru Limited | Agriculture & fishing | 2023 |
| Silvasheep Limited | Agriculture & fishing | 2021 |
| Silverthorne Hobbs Limited | Manufacturing | 2008 |
| Simon Lewis Consulting Ltd | Professional & scientific | 2025 |
| Simple 8 Theatre Company | Arts & recreation | 2010 |
| Simpson Architecture Ltd | Professional & scientific | 2021 |
| Sinclair Limited | Administrative & support | 1989 |
| SIX Oaks Renewable Energy Park Ltd | Energy | 2022 |
| Skin Body Beauty Limited | Other services | 2024 |
| Skinbunny Limited | Wholesale & retail | 2023 |
| SKS Marketing Consultancy Ltd | Professional & scientific | 2020 |
| SL Building Maintenance Ltd | Construction | 2025 |
| Slatters Butchers Limited | Wholesale & retail | 2022 |
| Sleep Joy Limited | Health & social care | 2020 |
| Slingshot PR Ltd | Professional & scientific | 2020 |
| Slycker Limited | Wholesale & retail | 2021 |
| Smarts Fish & Chips Witney Limited | Hospitality | 2024 |
| SMR Group Limited | Financial services | 2007 |
| SMR Properties Limited | Construction | 2013 |
| SND Educational Consulting Ltd | Education | 2018 |
| Sndl Management Limited | Professional & scientific | 2023 |
| Snse Limited | Real estate | 2021 |