| IN House Industries Ltd | Wholesale & retail | 2016 |
| Incircles Photography Ltd | Professional & scientific | 2017 |
| Indel Ltd | Information & communication | 2024 |
| Independence at Home Limited | Health & social care | 2021 |
| Industrial Batteries (UK) Limited | Wholesale & retail | 1997 |
| Industrial FAN Services Limited | Manufacturing | 2003 |
| Industrial Machinery (Services) Limited | Administrative & support | 2014 |
| Ineffable Innovations Ltd | Manufacturing | 2019 |
| Infinite Wisdom Productions Limited | Information & communication | 2007 |
| Infinite Wisdom Studios Limited | Professional & scientific | 2011 |
| Inglecote Consultancy Limited | Information & communication | 2012 |
| Inglecote Property Limited | Real estate | 2019 |
| Inkford Court Lettings Limited | Hospitality | 2014 |
| Inlife Design Ltd. | Information & communication | 2007 |
| INNOV4TE Education and Training Ltd | Education | 2022 |
| Innovatest UK Ltd | Professional & scientific | 2021 |
| Innovo Denture Laboratories Ltd | Other services | 2017 |
| Innovo Digital Ltd | Manufacturing | 2022 |
| Inrock Limited | Construction | 1997 |
| Insight Investigations Limited | Administrative & support | 1996 |
| Insight Meetings Ltd | Education | 2025 |
| Insight Security Management Limited | Administrative & support | 2006 |
| Insley Properties Ltd | Real estate | 2024 |
| Inspire Partners Consulting Ltd | Professional & scientific | 2025 |
| Inspiring Hope Ltd. | Administrative & support | 2017 |
| Inspiring Partnerships Limited | Administrative & support | 2002 |
| Instalair Vented Services Limited | Construction | 2006 |
| Install (Ceilings & Partitions) Limited | Construction | 2003 |
| Instant Resource Ltd | Administrative & support | 2025 |
| Intelligent Lighting Solutions Limited | Construction | 2013 |
| Intentional Designs Ltd | Manufacturing | 2013 |
| Interdecs Maintenance Ltd | Construction | 2020 |
| Interface Security Systems Limited | Other services | 1991 |
| Interiors by Kitch Ltd | Professional & scientific | 2025 |
| Interlift Group UK Ltd | Construction | 2020 |
| International Holdings Limited | Professional & scientific | 2001 |
| Interplay Sales & Marketing Limited | Administrative & support | 1999 |
| Intranet Consulting (UK) Limited | Information & communication | 2003 |
| Invencept Ltd | Professional & scientific | 2012 |
| Inverted Lift Solutions Ltd | Manufacturing | 2024 |
| Invictus BT Limited | Professional & scientific | 2023 |
| Iron Oxide Design Limited | Manufacturing | 2016 |
| Ironstack AI Limited | Information & communication | 2026 |
| IS Purewal Consulting Limited | Professional & scientific | 2011 |
| Isaac Mercer Limited | Professional & scientific | 2013 |
| ISG - Indoor Simulation Golf Ltd | Hospitality | 2024 |
| ISR Property Partners Limited | Real estate | 2022 |
| Israel and Sons Limited | Water & waste | 2020 |
| IT Insight Group Ltd | Information & communication | 2026 |
| IT Techno-Phobes Limited | Information & communication | 2016 |
| Itzkayzfx Ltd | Education | 2025 |
| IVY Realty Ltd | Real estate | 2024 |
| Iwona Properties Ltd | Real estate | 2018 |
| IWS Pudsey Limited | Information & communication | 2013 |
| J & O Leisure Ltd | Hospitality | 2025 |
| J a B Plant Hire Limited | Administrative & support | 2018 |
| J a Bedward & SON Limited | Construction | 2008 |
| J B Manas Ltd | Wholesale & retail | 2026 |
| J Coope Limited | Real estate | 2016 |
| J H Business Forms Limited | Manufacturing | 1979 |
| J L J Healthcare Limited | Wholesale & retail | 1999 |
| J Milne Group Limited | Financial services | 2017 |
| J N Hector Services Ltd | Transport & logistics | 2020 |
| J P Bolts Ltd | Wholesale & retail | 2001 |
| J P Donovan Limited | Administrative & support | 2009 |
| J P L Developments Limited | Real estate | 2004 |
| J P L Print & Design Limited | Manufacturing | 2002 |
| J S Transportation Ltd | Transport & logistics | 2017 |
| J Scott EDM Ltd | Professional & scientific | 2021 |
| J Sira Engineering Ltd | Manufacturing | 2018 |
| J&C Transportation Ltd | Transport & logistics | 2025 |
| J&M Amusements Holdings Limited | Financial services | 2025 |
| J&M Amusements Limited | Financial services | 2025 |
| J&M Electrical Solutions Ltd | Construction | 2010 |
| J. Bros Developments Ltd | Construction | 2019 |
| J. Kaye Painting & Decorating Services Ltd | Administrative & support | 2008 |
| J. Mcintosh and Family Limited | Real estate | 2020 |
| J.E.Taylor & SON Limited | Other services | 1935 |
| J.R.Bains Properties Ltd | Real estate | 2025 |
| J.R.R Properties Ltd | Real estate | 2019 |
| J.T. Rentals Limited | Real estate | 1979 |
| J.W. Treadwell Limited | Wholesale & retail | 1957 |
| JAC Transport Ltd | Transport & logistics | 2016 |
| Jack and Jill's Day Nursery Ltd | Health & social care | 2019 |
| Jack in the Box Pre-School Limited | Education | 2012 |
| Jack Stuart Electrical Ltd | Construction | 2017 |
| Jack's Union Limited | Professional & scientific | 2009 |
| Jackie Roberts Limited | Wholesale & retail | 1989 |
| Jackson Retail Group Black Country Ltd | Wholesale & retail | 2025 |
| Jackson Taft Securities Ltd | Financial services | 2022 |
| Jacksons Pharma Ltd | Wholesale & retail | 2013 |
| Jade Metals Ltd | Wholesale & retail | 2020 |
| Jagdroid Limited | Manufacturing | 2020 |
| JAK Hereford Limited | Wholesale & retail | 2019 |
| Jake Consultancy Ltd | Health & social care | 2022 |
| Jake Watson Plastering Ltd | Construction | 2022 |
| Jakebe Consultancy Services Ltd | Professional & scientific | 2019 |
| Jalise Properties Limited | Construction | 1968 |
| James Kitchen & Electrical Installations Ltd | Construction | 2011 |
| James Property Rentals Limited | Real estate | 2025 |