| IM Project & Interim Management Limited | Professional & scientific | 2004 |
| Impact Training Club Ltd | Arts & recreation | 2022 |
| In-It-Goes Recycling Equipment Limited | Administrative & support | 2012 |
| Income Protection Expert Ltd | Information & communication | 2014 |
| Indian Takeaway Rushden Ltd | Hospitality | 2023 |
| Industrial Controls (Anglia) Limited | Extraterritorial | 1985 |
| Industrial Maintenance Training Ltd | Education | 2009 |
| Indysaab Limited | Wholesale & retail | 2012 |
| Infinitelimits Ltd | Information & communication | 2018 |
| Infinity Gridworks Ltd | Construction | 2017 |
| Infinity IT Traders Limited | Wholesale & retail | 2025 |
| Inflatable Total Bounceout Ltd | Arts & recreation | 2025 |
| Innoventor Technical Services Ltd | Information & communication | 2012 |
| Inrean UK Ltd | Real estate | 2014 |
| Insequa Limited | Professional & scientific | 2012 |
| Inspired Estate Agents Rushden Ltd | Real estate | 2024 |
| Inspired Sales and Lettings Rushden Ltd | Real estate | 2019 |
| Integrated Resilience Services Ltd | Information & communication | 2025 |
| Inter County Cleaning Services Limited | Extraterritorial | 2013 |
| Interlynx Security Ltd | Administrative & support | 2001 |
| International Fruits and VEG Ltd | Wholesale & retail | 2026 |
| International Safety Products Limited | Manufacturing | 2019 |
| Irieman Limited | Transport & logistics | 2023 |
| Ironbark Capital Limited | Financial services | 2011 |
| Ironfang K9 Protection Ltd | Administrative & support | 2025 |
| Isdecorafest UK Ltd | Wholesale & retail | 2023 |
| Islands View Cafe and Tackle Ltd | Hospitality | 2023 |
| IT9 Ltd | Information & communication | 2024 |
| IVB Transportation Ltd | Wholesale & retail | 2020 |
| Ixus Limited | Construction | 2005 |
| J a Construction Site Services Ltd | Construction | 2019 |
| J a Miller Carpentry Ltd | Construction | 2020 |
| J D GAS & Heating Limited | Construction | 2017 |
| J D Parker Ltd | Financial services | 2016 |
| J Immaculate Care Limited | Health & social care | 2015 |
| J Immaculate Services Limited | Health & social care | 2020 |
| J Kemp FD Consultancy Limited | Professional & scientific | 2021 |
| J T P Leisure Ltd | Arts & recreation | 2021 |
| J W Mortgages Limited | Financial services | 2016 |
| J&J Carpentry Contractors Limited | Construction | 2026 |
| J&J Recruitment Services Ltd | Administrative & support | 2019 |
| J&S Artisans Ltd | Wholesale & retail | 2022 |
| J. Hanvey & Sons Ltd | Other services | 2023 |
| J. Osborne Property Ltd | Real estate | 2026 |
| J. Piecha Social Work Services Ltd | Health & social care | 2023 |
| J.H.May(Electrical)Limited | Construction | 1958 |
| J.Mitchinson Engineering Ltd | Manufacturing | 2015 |
| Jack of ALL Maids Ltd | Administrative & support | 2025 |
| JAF Contracts Limited | Construction | 1994 |
| Jam-Out Junction Ltd | Education | 2025 |
| James Barnett Transport Limited | Transport & logistics | 2026 |
| Jans Floral Boutique Limited | Wholesale & retail | 1964 |
| Jas(Gb) Ltd | Real estate | 2020 |
| Jazz Construction Bedford Ltd | Construction | 2020 |
| Jazz School UK Ltd | Education | 2014 |
| JB Amusements Ltd | Arts & recreation | 2023 |
| JB Builders and Sons Ltd | Construction | 2022 |
| JB JOE Limited | Administrative & support | 2026 |
| JB Maintenance Ltd | Administrative & support | 2026 |
| JB Rhodes Ltd | Wholesale & retail | 2023 |
| JB Tech Ltd | Information & communication | 2023 |
| JB Track Bike Hire Ltd | Administrative & support | 2017 |
| JCB Continental Ltd | Hospitality | 2023 |
| JD Handyman Services Limited | Construction | 2025 |
| JD Professional Haircare Limited | Wholesale & retail | 2016 |
| JDG Automotive Ltd | Administrative & support | 2015 |
| JDG Property Ltd | Real estate | 2020 |
| JDS Mechanical Ltd | Construction | 2025 |
| JDW Brickwork & Construction Limited | Construction | 2019 |
| JEM Haven Limited | Real estate | 2024 |
| Jemimamc Estates Ltd | Real estate | 2026 |
| Jensen Holmes Funfair Ltd | Arts & recreation | 2024 |
| Jervis Limited | Professional & scientific | 2009 |
| JET Haul Transports Ltd | Transport & logistics | 2025 |
| Jeyes Enterprises Limited | Households | 2022 |
| JFM Engineering Limited | Professional & scientific | 2022 |
| JGB Electrical Services Limited | Construction | 2017 |
| JH Paintworx Ltd | Professional & scientific | 2019 |
| Jireh & Aawoche Ltd | Health & social care | 2023 |
| JJ Driving Services Limited | Transport & logistics | 2021 |
| JKK Property Invest UK Ltd | Real estate | 2024 |
| JLC Property Investments 2025 Ltd | Real estate | 2025 |
| JM Air Conditioning Services Ltd | Construction | 2023 |
| JMB Roofing Ltd | Construction | 2023 |
| JMC Cleaning Contractors Ltd | Administrative & support | 2018 |
| JMK Renovations Ltd | Construction | 2021 |
| JMP Creative Limited | Professional & scientific | 2025 |
| JN Sales & Marketing Ltd | Professional & scientific | 2024 |
| JNJ Investments Ltd | Real estate | 2024 |
| John Maxwell Engineering Limited | Professional & scientific | 2002 |
| John Thurston & SON Limited | Arts & recreation | 1947 |
| Jones & Co Solutions Ltd | Administrative & support | 2022 |
| Jonette Catering Ltd | Manufacturing | 2020 |
| Jordaya Contracting Limited | Construction | 2009 |
| Joselby Limited | Health & social care | 2023 |
| Joshiem Grace Ltd | Wholesale & retail | 2023 |
| JRM Property Maintenance Limited | Construction | 2025 |
| Jsouthorn Design Ltd | Professional & scientific | 2018 |
| JTC Consultants Ltd | Professional & scientific | 2014 |
| JTS Mobile Tyres Limited | Wholesale & retail | 2012 |