| Inkpot and Press Media Services Limited | Professional & scientific | 2016 |
| Innovate Automotive Limited | Wholesale & retail | 2021 |
| Innovation Wireless Ltd | Manufacturing | 2012 |
| Inside Care Ltd | Transport & logistics | 2021 |
| Insight Construction (Midlands) Ltd | Construction | 2022 |
| INSIGHT2INSPIRE Ltd | Professional & scientific | 2026 |
| Insightlenses Ltd | Wholesale & retail | 2011 |
| Inspiral Property Limited | Construction | 2008 |
| Inspire Architectural Tiles Ltd | Wholesale & retail | 2020 |
| Inspired Scaffolding Services Limited | Construction | 2010 |
| Inspired Site Services Limited | Extraterritorial | 2014 |
| Insurefinity Limited | Extraterritorial | 2023 |
| Insurelance Ltd. | Financial services | 2014 |
| Integritas Solutions Limited | Professional & scientific | 2019 |
| Intelli-Hood (UK) Limited | Manufacturing | 2026 |
| Inter Car Cleaning Swindon Ltd | Other services | 2024 |
| Interchangehr Ltd | Professional & scientific | 2024 |
| Interface UP Limited | Information & communication | 2016 |
| International Export Packers Limited | Manufacturing | 1998 |
| International Logistics Centre Limited | Other services | 2016 |
| International Ocean Rowing Limited | Other services | 2016 |
| International Woodworking Machinery Limited | Wholesale & retail | 2009 |
| Interview Coaching and Confidence (ICC) Ltd | Administrative & support | 2025 |
| Into Europe Consulting Ltd | Professional & scientific | 2024 |
| Into the Woods Marketing Limited | Professional & scientific | 2021 |
| Inventor Vyse Limited | Manufacturing | 2023 |
| Investment for Life Limited | Financial services | 2001 |
| Invisible Communications Limited | Education | 1993 |
| Invisible Dragon Ltd | Wholesale & retail | 2018 |
| Irish Groupage Services Limited | Transport & logistics | 1995 |
| Isabella Wallace Limited | Professional & scientific | 2013 |
| Isiap Property Limited | Real estate | 2019 |
| Isla Therapies Ltd | Health & social care | 2023 |
| Isoflo Ltd | Construction | 2020 |
| ISP Developments Bilsthorpe Limited | Construction | 2020 |
| ISP Developments Edwinstowe Limited | Construction | 2022 |
| ISP Developments Limited | Construction | 2005 |
| ISP Developments Southwell Limited | Construction | 2017 |
| ITG Physical Training Ltd | Arts & recreation | 2013 |
| ITU Health Care Provider Ltd | Health & social care | 2015 |
| Ivepa Post Limited | Information & communication | 2016 |
| IVY Construction (Newark) Limited | Construction | 2023 |
| Iwec Ltd | Construction | 2019 |
| J & a Farming Ltd | Agriculture & fishing | 2007 |
| J & C Pearce Investments Limited | Financial services | 2018 |
| J & J Burnett Limited | Agriculture & fishing | 1989 |
| J & W Services Ltd | Construction | 2021 |
| J and J Noutch Limited | Agriculture & fishing | 2011 |
| J Bentley Consulting Ltd | Professional & scientific | 2022 |
| J Berry Associates Ltd | Professional & scientific | 2010 |
| J Butcher Building Services Ltd | Construction | 2014 |
| J C Naish Ltd | Real estate | 2021 |
| J C R 2008 Limited | Administrative & support | 2008 |
| J C Surfacing Ltd | Construction | 2014 |
| J D Warrington Builders Limited | Construction | 2006 |
| J Davies Group Limited | Financial services | 2024 |
| J Fletch Elec Ltd | Construction | 2019 |
| J L P Holdings Ltd | Construction | 2016 |
| J M N S Property Services Limited | Construction | 2013 |
| J Martin Property Ltd | Real estate | 2025 |
| J P Architectural Sales Ltd | Wholesale & retail | 2025 |
| J R Oliver Farming Limited | Agriculture & fishing | 2019 |
| J Rose Holdings Ltd | Financial services | 2023 |
| J&N Consultants (Nottingham) Limited | Professional & scientific | 2019 |
| J&S Buildit Limited | Construction | 2019 |
| J-Tech-Maintenance Services Limited | Construction | 2025 |
| J. Devos (Newark) Limited | Construction | 2001 |
| J.A.C. Construction UK Limited | Real estate | 1997 |
| J.J. Malbert Limited | Professional & scientific | 2021 |
| J.S.Dakin & Company | Agriculture & fishing | 1947 |
| J.T Electrical Installation and Testing Limited | Construction | 2013 |
| J.W.R.Beckitt(Hill Farm,Egmanton)Limited | Agriculture & fishing | 1964 |
| Jaaky Trans Ltd | Transport & logistics | 2018 |
| Jacal Consultants Ltd | Professional & scientific | 2025 |
| Jack Chick Limited | Professional & scientific | 2016 |
| Jackson & SON Properties Ltd | Real estate | 2022 |
| Jackson Electronics Limited | Manufacturing | 1999 |
| Jackson Mattock Properties Ltd | Real estate | 2021 |
| Jacob's Homes Limited | Health & social care | 2024 |
| JAGETYP01 Limited | Administrative & support | 2022 |
| JAK Developments Limited | Real estate | 2025 |
| JAK Estates Ltd | Real estate | 2021 |
| Jake Morley Commercial Services Ltd | Professional & scientific | 2022 |
| Jaloos Limited | Administrative & support | 2023 |
| Jamba Trade UK Ltd | Wholesale & retail | 2025 |
| James Burnett Limited | Agriculture & fishing | 2018 |
| James Larkin Services Ltd | Professional & scientific | 2025 |
| James Miller (Kelham) Limited | Agriculture & fishing | 2004 |
| Jamie Brown Landscapes Ltd | Administrative & support | 2021 |
| Jamie Falvey Racing Limited | Arts & recreation | 2019 |
| Jane Bellhouse Limited | Administrative & support | 2006 |
| Jane Young (Fashions) Limited | Wholesale & retail | 1964 |
| Jarvis Flooring Ltd | Construction | 2024 |
| Jarvis Property Partners Limited | Real estate | 2025 |
| Jasmine IT Services Limited | Information & communication | 2018 |
| JAY One Events Limited | Administrative & support | 2024 |
| Jaystones Ltd | Construction | 2025 |
| Jazmin Properties Ltd | Real estate | 2024 |
| Jazmin Stays Ltd | Real estate | 2024 |
| JB Builders (Newark) Limited | Construction | 2005 |