| INK & Wild Ltd | Wholesale & retail | 2025 |
| INK Elves Ltd | Information & communication | 2013 |
| Inmh Group Ltd | Wholesale & retail | 2019 |
| Innisdoon Estates Limited | Real estate | 2017 |
| Innova Communications Limited | Information & communication | 2023 |
| Innovatemarket Limited | Extraterritorial | 2023 |
| Innovation Branding Ltd | Other services | 2025 |
| Innovus DG Limited | Information & communication | 2021 |
| Inplace Personnel Services Ltd | Administrative & support | 2007 |
| Insideout Garden Living Ltd | Professional & scientific | 2018 |
| Inspire Homes and Care Limited | Real estate | 2020 |
| Inspired Minds Hub Ltd | Health & social care | 2024 |
| Installation Services Limited | Construction | 2018 |
| Insugreen Ltd | Information & communication | 2022 |
| Insulated Glass Limited | Manufacturing | 2023 |
| Insulation Partners Ltd | Construction | 2025 |
| Insurance Administration Services Limited | Financial services | 1994 |
| Insurance Consultants International Limited | Financial services | 2003 |
| Integra Window Systems Limited | Wholesale & retail | 2016 |
| Integral HSE Limited | Professional & scientific | 2011 |
| Integrated Risk Management Limited | Professional & scientific | 2006 |
| Intellex Coaching Ltd | Administrative & support | 2023 |
| Intelligent Recording Limited | Manufacturing | 2008 |
| Intequal Contracting Ltd | Construction | 2026 |
| Inter School Travel Holdings Limited | Financial services | 2024 |
| Inter School Travel Limited | Administrative & support | 1970 |
| Inter-Mind Psychological Services Ltd | Health & social care | 2015 |
| Interactive People Development Limited | Professional & scientific | 2001 |
| Intercontinental Transport Solutions Ltd | Transport & logistics | 2026 |
| Interflex Electrical Engineering Limited | Construction | 2007 |
| Interim Consultancy Limited | Administrative & support | 2025 |
| Interim Enterprises Management & Consultancy Services Limited | Administrative & support | 2016 |
| Interior Revival Company Limited | Other services | 2011 |
| Interiors Foam Limited | Manufacturing | 2003 |
| International Business Consulting Ltd | Wholesale & retail | 2015 |
| International Cricket Masters Ltd | Arts & recreation | 2015 |
| International Greyhound Services Ltd | Financial services | 2023 |
| International Media Partner Ltd | Wholesale & retail | 2026 |
| Internet of Things Academy Ltd | Education | 2016 |
| Interseal UK Limited | Construction | 2005 |
| Interski Limited | Professional & scientific | 1983 |
| Intex Fabrications Ltd | Manufacturing | 2023 |
| Intouch Solutions Ltd | Professional & scientific | 2018 |
| Intuboxing Ltd | Professional & scientific | 2017 |
| Invatech IT Solutions Limited | Information & communication | 2006 |
| Invested Athlete Limited | Wholesale & retail | 2026 |
| Invictus Security Group Limited | Administrative & support | 2019 |
| ION Foundry Ltd | Manufacturing | 2020 |
| IOV Ltd | Transport & logistics | 2022 |
| Iplay Water Attractions (UK) Ltd | Arts & recreation | 2018 |
| IPS Holdings (Worksop) Limited | Financial services | 2022 |
| IPS Property Solutions Limited | Construction | 2020 |
| IPS Renewables Ltd | Construction | 2023 |
| Ipsum Renewables Ltd | Construction | 2017 |
| Iqra Food Nottingham Limited | Hospitality | 2024 |
| Irbe Ltd | Transport & logistics | 2026 |
| Irefurbished Limited | Wholesale & retail | 2025 |
| Iron Vein Ltd | Hospitality | 2019 |
| IS Groundworks Limited | Construction | 2016 |
| ISC (Galbraith) Holdings Ltd | Financial services | 2024 |
| Ishaan Enterprise Limited | Hospitality | 2024 |
| Ishiv Mansfield Ltd | Wholesale & retail | 2017 |
| Island Quarter Hairdressing Limited | Other services | 2023 |
| ISM Wealth Planning LLP | | 2017 |
| Ismail Galaxy Construct Ltd | Manufacturing | 2026 |
| Israel K Ltd | Health & social care | 2025 |
| Israel Newton & Sons Limited | Manufacturing | 2007 |
| Isterling's Ltd | Wholesale & retail | 2018 |
| IT Cadets Ltd | Education | 2018 |
| It-To-Ot Ltd | Professional & scientific | 2012 |
| Itfi Ltd | Information & communication | 2023 |
| Itify Ltd | Information & communication | 2017 |
| Itsolutionmdm Limited | Professional & scientific | 2022 |
| Iulconstruct Limited | Construction | 2025 |
| Ivan Bramley Holdings Limited | Financial services | 2022 |
| Ivan Bramley Limited | Other services | 2019 |
| Ivanello Investments Ltd | Construction | 2021 |
| Ivteam Ltd | Education | 2007 |
| Iwan Transport Ltd | Transport & logistics | 2017 |
| Ixedrea Ltd | Wholesale & retail | 2024 |
| Izoma Property Management Ltd | Real estate | 2024 |
| Izwi Ltd | Health & social care | 2025 |
| J & J Housing Solutions Ltd | Real estate | 2023 |
| J a Johnson (Benniworth) Ltd | Financial services | 2018 |
| J and L Accountants Limited | Professional & scientific | 2005 |
| J Barsby Electrical Ltd | Construction | 2008 |
| J D Groundworks (Midlands) Limited | Construction | 2018 |
| J Daly Limited | Construction | 2019 |
| J G Concepts Limited | Professional & scientific | 1999 |
| J H Wood Discretionary Trust Ltd | Professional & scientific | 2025 |
| J I Wigley Limited | Agriculture & fishing | 2013 |
| J K L Investments Limited | Real estate | 2005 |
| J K S - Boyles UK Limited | Mining & quarrying | 2001 |
| J KAY Construction Limited | Construction | 2023 |
| J Kirkham Flooring Limited | Construction | 2014 |
| J P R Property Management Limited | Real estate | 2005 |
| J Precision Hooks Ltd | Agriculture & fishing | 2017 |
| J S Hayre Properties & Lettings Limited | Real estate | 2021 |
| J S Trustee Ltd | Extraterritorial | 2021 |
| J&A Nailcare Ltd | Other services | 2025 |