| Noirstudio KJ Limited | Other services | 2024 |
| Nordland Landscapes Limited | Administrative & support | 2018 |
| Noreldeen Limited | Health & social care | 2013 |
| Oliver Events Ltd | Other services | 2023 |
| One Full Round CIC | Education | 2026 |
| Onepack Compliance Limited | Professional & scientific | 2009 |
| Optical Metrology Services Limited | Professional & scientific | 2004 |
| Orange Meet & Greet Ltd | Hospitality | 2024 |
| Osprey Network & Communications Limited | Information & communication | 1990 |
| Ostium Consulting Limited | Professional & scientific | 2019 |
| P&M Langley Ltd | Hospitality | 2017 |
| Paola's Cafe Stansted Ltd | Hospitality | 2023 |
| Parapluie Studio Ltd | Other services | 2025 |
| Parkland Plumbing & Heating Limited | Construction | 2000 |
| Patrick Howard Design Associates LLP | | 2019 |
| PBC Cars Ltd | Transport & logistics | 2023 |
| PDR Infra Advisory Limited | Professional & scientific | 2018 |
| Peerless Europe Ltd. | Manufacturing | 1991 |
| Peter James Limited | Real estate | 2016 |
| PHD (London) Limited | Construction | 2011 |
| Photon Engineering Europe Limited | Manufacturing | 2023 |
| Piercd Ltd | Wholesale & retail | 2023 |
| Pigram & Co Limited | Professional & scientific | 2010 |
| Pigram Holdings Limited | Financial services | 2010 |
| Pixies Pre-School Ltd | Health & social care | 2020 |
| PJ Mulhall Brokers Ltd | Financial services | 2023 |
| Plan B Club Ltd | Information & communication | 2018 |
| Plan Building Limited | Construction | 2017 |
| PMG Travel Ltd | Transport & logistics | 2024 |
| Pock (Investments) Limited | Financial services | 2018 |
| Poodle Creative Limited | Professional & scientific | 2021 |
| Popcorn Web Design Limited | Information & communication | 2015 |
| Porta Digital Ltd | Information & communication | 2026 |
| Porta Ostra Limited | Manufacturing | 2026 |
| Portland Property Services Limited | Real estate | 2001 |
| Praslin Productions Limited | Information & communication | 2009 |
| Precision Gate Services Ltd | Construction | 2025 |
| Presidione Ltd | Construction | 2018 |
| Preston Legal Services Limited | Professional & scientific | 2016 |
| Prestwick Aero Limited | Transport & logistics | 2003 |
| Priory Field Residents Management Company Limited | Households | 2025 |
| Proud Works Ltd | Wholesale & retail | 2022 |
| Psychiatry at Cambridge Ltd | Health & social care | 2022 |
| Radhe Krishana Construction Ltd | Construction | 2024 |
| Rage Group Ltd | Other services | 2022 |
| Rage Waste Services Ltd | Water & waste | 2023 |
| Ragewear Ltd | Other services | 2026 |
| Rainbow Pre-School (Stansted) | Education | 2004 |
| Rainford's Maintenance and Decorating Specialists Limited | Construction | 2017 |
| Ramp Instruments & Controls Limited | Wholesale & retail | 2002 |
| RAR Property Group Ltd | Real estate | 2024 |
| Ravina Limited | Hospitality | 2025 |
| RDC SW14 Ltd | Health & social care | 2023 |
| Real Group Limited | Information & communication | 2008 |
| RECRUIT4GAMES Limited | Administrative & support | 2025 |
| Regent Estate Services Ltd | Wholesale & retail | 2024 |
| Regent Prospects Limited | Real estate | 2025 |
| Reliapay Ltd | Professional & scientific | 2024 |
| REN Projects Ltd | Administrative & support | 2025 |
| Renovate Interiors Limited | Construction | 2025 |
| Rickling Green Construction Limited | Construction | 2024 |
| RLE International Product Development Ltd | Professional & scientific | 1998 |
| RM Plastering and Designs Limited | Construction | 2025 |
| Robert Brimblecombe Business Communications Limited | Information & communication | 2010 |
| Roberts HAY Partnership Limited | Construction | 2003 |
| Robinson & Co Holdings Ltd | Financial services | 2021 |
| Robinson Global Limited | Administrative & support | 2013 |
| Roger Direct Limited | Extraterritorial | 2015 |
| Room at the Top Limited | Administrative & support | 2017 |
| Room at the Top Lofts Limited | Construction | 2024 |
| Rosa Lupus Ltd | Real estate | 2024 |
| Rstw Holdings Limited | Wholesale & retail | 2019 |
| Rubyte Limited | Administrative & support | 2017 |
| Ruggiero Ltd | Professional & scientific | 2017 |
| Ryanair UK Limited | Transport & logistics | 1985 |
| Ryanstone Limited | Construction | 2003 |
| Samantha Court Management Ltd | Households | 2022 |
| Saralys Limited | Hospitality | 2003 |
| SAS Group Holdco Ltd | Financial services | 2026 |
| SAS Group Ltd | Construction | 2018 |
| SAS Group Property Ltd | Real estate | 2026 |
| Scholars Quest Limited | Education | 2007 |
| Scribble and Click Ltd | Professional & scientific | 2014 |
| SD Jones Trading Limited | Administrative & support | 2009 |
| Sensor Agility Ltd | Extraterritorial | 2012 |
| Shape HR Consulting Ltd | Professional & scientific | 2016 |
| Sharon Inns Limited | Administrative & support | 2023 |
| SHE of the Sea Ltd | Education | 2024 |
| SHJ Flooring Ltd | Construction | 2022 |
| Shop 4 Windows Ltd | Construction | 2004 |
| Siignals Limited | Manufacturing | 1999 |
| Silva Place Management Ltd | Households | 2019 |
| Simanda Limited | Construction | 1995 |
| SINCLAIR6687 Limited | Construction | 2025 |
| Sirijas Limited | Health & social care | 2018 |
| Skillsphere VR Ltd | Education | 2023 |
| Skiwise Limited | Extraterritorial | 2007 |
| Skylark Engineering Limited | Manufacturing | 2007 |
| Smart Transport Solutions Ltd | Transport & logistics | 2016 |
| Snowjet Limited | Extraterritorial | 2006 |