| Red Marble Design Ltd | Professional & scientific | 2013 |
| Red Mercury Studio Limited | Professional & scientific | 2018 |
| Red on White Consulting Ltd | Professional & scientific | 2020 |
| Red Property Investments Ltd | Real estate | 2016 |
| Red Robins Nannery Ltd | Health & social care | 2019 |
| Red Rook 3D Ltd | Professional & scientific | 2018 |
| Red Rosette Ltd | Agriculture & fishing | 2023 |
| Red Star Security Ltd | Other services | 2023 |
| Red Tail Design Ltd | Information & communication | 2009 |
| Red Talks Ltd | Professional & scientific | 2026 |
| Red TIE (Group) Limited | Information & communication | 2007 |
| Red TIE Limited | Information & communication | 2002 |
| Red Wine Mary Limited | Extraterritorial | 2025 |
| Red-Equip Ltd | Construction | 2025 |
| RED4ORD Garden Services Ltd | Administrative & support | 2019 |
| Redbook Accounting Limited | Professional & scientific | 2011 |
| Redbox Pro Limited | Information & communication | 2018 |
| Reddsand Ltd | Information & communication | 2015 |
| Reddy & Reddy Limited | Real estate | 2013 |
| Reddys Management Consultancy Limited | Professional & scientific | 2019 |
| Rede 2 Invest Property Limited | Real estate | 2025 |
| Redford O'Neill Consulting Ltd | Professional & scientific | 2013 |
| Redhouse Road Management Company Limited | Real estate | 1988 |
| Redlands Group Limited | Professional & scientific | 2017 |
| Redmine Networks Ltd | Information & communication | 2012 |
| Redpalm Group Limited | Financial services | 2023 |
| Redpalm Technology Services Ltd | Information & communication | 2010 |
| Redpost Fuels Limited | Wholesale & retail | 2012 |
| Redrock Ground Support Systems Ltd | Construction | 2018 |
| Redrock Hire Centres Ltd | Construction | 2009 |
| Redstar Global Solutions Ltd | Wholesale & retail | 2025 |
| Redu Developments Ltd | Real estate | 2019 |
| Redvan Bearings Limited | Wholesale & retail | 2011 |
| Redwell Mews Management Company Limited | Professional & scientific | 1989 |
| Redwood Benefit Services Limited | Financial services | 2020 |
| Redwood Estates (Northampton) Ltd | Real estate | 2013 |
| Redyt Limited | Information & communication | 2023 |
| Reece Thomas Reuben Munro-Hughes Ltd | Extraterritorial | 2025 |
| Reedhill Properties Ltd | Households | 2025 |
| Reedmore Holdings Ltd | Real estate | 2022 |
| Reeds (Oxon) Limited | Wholesale & retail | 2013 |
| Reefyll Limited | Wholesale & retail | 2022 |
| Reeko Ltd | Wholesale & retail | 2025 |
| Reel People Ltd | Professional & scientific | 2021 |
| Reel Tech UK Ltd | Wholesale & retail | 2009 |
| Rees Media and Marketing Limited | Professional & scientific | 2023 |
| Reeve Vehicle Repairs Ltd | Wholesale & retail | 2026 |
| Refcomm Limited | Professional & scientific | 2019 |
| Refine Learning Ltd | Education | 2021 |
| Refinebuild Construction Ltd | Manufacturing | 2025 |
| Refined Consulting Limited | Administrative & support | 2024 |
| Refinish Solutions Ltd | Wholesale & retail | 2012 |
| Reflection Ismat Ltd | Wholesale & retail | 2019 |
| Reflectric Ltd | Information & communication | 2018 |
| Reflow Finance Ltd | Extraterritorial | 2023 |
| Reform Trading Ltd | Other services | 2023 |
| Refuel Inc Northampton Ltd | Wholesale & retail | 2026 |
| Refurb Project Ltd | Construction | 2009 |
| REG Services Limited | Information & communication | 2021 |
| Regal Cars Northampton Ltd | Transport & logistics | 2025 |
| Regal House Management Company Limited | Households | 1996 |
| Regal Parcel Ltd | Wholesale & retail | 2026 |
| Regal Vision Ltd | Construction | 2021 |
| Regence Ltd | Administrative & support | 2019 |
| Regency Inns Ltd | Hospitality | 2019 |
| Regent Construction Northampton Ltd | Construction | 2025 |
| Regent Street RTM Company Limited | Households | 2021 |
| Regents Gate Management (Northampton) Limited | Households | 2000 |
| Regional Home From Home Ltd | Health & social care | 2015 |
| Regional Security Specialists Limited | Administrative & support | 2023 |
| Regis Interiors Limited | Manufacturing | 2013 |
| Regulis Limited | Manufacturing | 2003 |
| Rehab Arts Ltd. | Health & social care | 2026 |
| Rehoboth Recruitments Limited | Health & social care | 2017 |
| Reid Consulting Emea Limited | Information & communication | 2024 |
| Reigate Roofing Ltd | Construction | 2021 |
| Reign Transports & Courier Logistics Ltd | Transport & logistics | 2024 |
| Reilly Plant Sales Ltd | Wholesale & retail | 2023 |
| Reimagined Quality Limited | Hospitality | 2021 |
| Reitz Consulting Limited | Professional & scientific | 2012 |
| Relan Corporation Ltd | Financial services | 2017 |
| Relans Development Limited | Construction | 2010 |
| Relating.To Limited | Information & communication | 2010 |
| Reliable Removals & Storage Ltd | Transport & logistics | 2024 |
| Reliant IT Consulting Ltd | Information & communication | 2025 |
| Relief Property Consult Ltd | Construction | 2019 |
| Relish the Taste Limited | Hospitality | 2023 |
| Relm Consultants Limited | Professional & scientific | 2015 |
| Relocate Property Ltd | Real estate | 2022 |
| Relstate Ltd | Information & communication | 2025 |
| Remarkable Success Ltd | Professional & scientific | 2006 |
| Remedy Hairdressing and Salon Training Limited | Other services | 2019 |
| Remedy Mind & Wellness Ltd | Health & social care | 2024 |
| Remedy Payroll Solutions Ltd | Financial services | 2020 |
| Remember Project Management Limited | Professional & scientific | 2025 |
| Remember the Future Ltd | Professional & scientific | 2022 |
| Remoex Limited | Wholesale & retail | 2025 |
| Remote Bookkeeping Solutions Limited | Professional & scientific | 2023 |
| Remote Crew Limited | Information & communication | 2025 |
| Remudy Limited | Professional & scientific | 2007 |