| Reliable Property Services Limited | Construction | 2019 |
| Renewable Energy Group Limited | Professional & scientific | 2003 |
| Renewable Energy Systems Holdings Limited | Professional & scientific | 2003 |
| Renewable Energy Systems Limited | Construction | 1981 |
| RES Development Company 23 Limited | Energy | 2024 |
| RES Development Company 36 Limited | Energy | 2025 |
| RES Development Company 37 Limited | Energy | 2025 |
| RES Development Company 38 Limited | Energy | 2025 |
| RES Development Company 39 Limited | Energy | 2025 |
| RES Development Company 40 Limited | Energy | 2025 |
| RES Digital Solutions Limited | Information & communication | 2024 |
| RES DS Holdings Limited | Financial services | 2024 |
| RES Energy Services Limited | Manufacturing | 2016 |
| RES Global Services Holdings Limited | Financial services | 2024 |
| RES Group Ventures Limited | Financial services | 2024 |
| RES UK & Ireland Limited | Administrative & support | 2003 |
| Reveal Residential Limited | Real estate | 2022 |
| Rexha Leisure Ltd | Hospitality | 2022 |
| RF Print Engineering Services Limited | Other services | 2003 |
| RGV (A19) Limited | Financial services | 2015 |
| RGV (M6) Limited | Financial services | 2015 |
| RGV Road Holdings Limited | Financial services | 2015 |
| Rightpak Ltd | Wholesale & retail | 2017 |
| Rinaree Limited | Manufacturing | 2013 |
| Rising Associates Ltd | Administrative & support | 2024 |
| RJ Meadway Consultants Limited | Professional & scientific | 2013 |
| RJA Advisory Limited | Professional & scientific | 2026 |
| RLX Business Partners Limited | Professional & scientific | 2025 |
| Roaring Hill Energy Storage Ltd | Energy | 2016 |
| Robert Mcalpine Enterprises Limited | Extraterritorial | 2000 |
| Robnor Investments Limited | Real estate | 1956 |
| Robur (U.K.) Limited | Wholesale & retail | 2023 |
| Rocket Site Designs Limited | Information & communication | 2022 |
| Rocks Management SPV Limited | Wholesale & retail | 2023 |
| Rodbaston Limited | Energy | 2013 |
| Romans 819 Ministries Limited | Other services | 2020 |
| Ronford Baker Engineering Company Limited | Professional & scientific | 1973 |
| Ronsec Security Worldwide Limited | Administrative & support | 2023 |
| Roos Energy Limited | Energy | 2011 |
| Roots to Roses Limited | Administrative & support | 2025 |
| Roscommon Estates Ltd | Construction | 2022 |
| Rose Meadows (Chiswell Green) Residents Management Company Limited | Households | 2026 |
| Rosefield Holdings Ltd | Financial services | 2026 |
| Roskrow Barton Limited | Energy | 2011 |
| Ross Hudson Electrical Ltd | Construction | 2015 |
| Roundforest UK Ltd | Wholesale & retail | 2025 |
| Rowlstone Recruitment Ltd | Information & communication | 2018 |
| Rsskl Ltd | Education | 1945 |
| RTK Property and Developments Ltd | Real estate | 2020 |
| Rubie Units Limited | Manufacturing | 2025 |
| Rubyblou Property Ltd | Real estate | 2018 |
| Runaway Solutions Limited | Information & communication | 2006 |
| Rybull Group Ltd | Real estate | 2024 |
| S Meehan Plant Hire Limited | Transport & logistics | 2015 |
| S P B Watford Limited | Construction | 2009 |
| S.A. York Design Facilities Limited | Professional & scientific | 1976 |
| Sabp Consulting Ltd | Professional & scientific | 2025 |
| Sachdev Consultancy Limited | Professional & scientific | 2010 |
| Safescaff Inspect Ltd | Construction | 2024 |
| Saffron Pharma Limited | Health & social care | 2024 |
| Salle Limited | Professional & scientific | 2013 |
| SAM1 Construction Ltd | Construction | 2020 |
| Sanamiee Limited | Professional & scientific | 2025 |
| Sancton Hill Limited | Energy | 1997 |
| Sandco 802 Limited | Professional & scientific | 2003 |
| Sanius Health Ltd | Information & communication | 2022 |
| Sarratt Office Supplies Limited | Wholesale & retail | 2004 |
| SAS Audit Limited | Professional & scientific | 2018 |
| SAS Funding Limited | Professional & scientific | 2021 |
| SAS Group Partners Limited | Financial services | 2024 |
| SAS Micro Limited | Professional & scientific | 2016 |
| SAS Tax Limited | Professional & scientific | 2018 |
| SAS Tech Limited | Information & communication | 2025 |
| Satin Ribbons and Pearls Ltd | Manufacturing | 2025 |
| Saunders and Sons Homes Ltd | Real estate | 2019 |
| Sbair Ltd | Wholesale & retail | 2024 |
| SBC Fleet Cleaning Limited | Administrative & support | 2025 |
| Scala Commercial Services Limited | Financial services | 2019 |
| Scala Property Services Ltd | Real estate | 2021 |
| Scaling Ecommerce Ltd | Professional & scientific | 2025 |
| SECUREX7 Ltd | Information & communication | 2024 |
| Seeable Limited | Information & communication | 2013 |
| Semekor Performing Arts Ltd | Transport & logistics | 2007 |
| Senacon Ltd | Professional & scientific | 2019 |
| SH Consult Limited | Professional & scientific | 2025 |
| Shah Co. UK Limited | Wholesale & retail | 2014 |
| Shah Consultants Limited | Information & communication | 2025 |
| Shala Stone Ltd | Manufacturing | 2023 |
| Shaneragh Energy Storage Limited | Energy | 2024 |
| Shanimovers Ltd | Transport & logistics | 2025 |
| Shelford Capital Ltd | Information & communication | 2018 |
| Shields Wealth Management Limited | Financial services | 2013 |
| Shine Assured Ltd | Administrative & support | 2021 |
| Shound Properties Limited | Real estate | 2017 |
| Sillen Limited | Wholesale & retail | 2021 |
| Silva Consulting Limited | Administrative & support | 2024 |
| Silver Squared Limited | Professional & scientific | 2011 |
| Simply Aquitaine Ltd | Administrative & support | 2022 |
| Simply Rentals Direct Ltd | Administrative & support | 2018 |
| Simtec Golf Ltd | Arts & recreation | 2024 |