| IBS Building Products Limited | Manufacturing | 1995 |
| Icare Living Limited | Health & social care | 2014 |
| Icde Consultancy Limited | Professional & scientific | 2020 |
| Icon Clothing Limited | Wholesale & retail | 2025 |
| ID Sofas Midlands Ltd | Manufacturing | 2018 |
| Ideal Employment Holdings Limited | Financial services | 2023 |
| Ideal Packaging Company Limited | Manufacturing | 2008 |
| Ideal Properties Group Ltd | Households | 2021 |
| Ieod Services Limited | Health & social care | 2022 |
| Ifediora Global Enterprises Limited | Wholesale & retail | 2022 |
| Ifire IT Consultancy Ltd | Information & communication | 2018 |
| IGO 15 Ltd | Construction | 2022 |
| IGO Estates Ltd | Real estate | 2023 |
| Ihaverse Ltd | Information & communication | 2026 |
| II Distribution Limited | Wholesale & retail | 2023 |
| IJ Properties Limited | Real estate | 2023 |
| IJ Utilities Limited | Financial services | 2024 |
| Ikar GB Limited | Manufacturing | 2008 |
| Ikis Fashions Ltd | Wholesale & retail | 2017 |
| Imagine ALL Destinations Limited | Hospitality | 2021 |
| Imani Pizza Limited | Hospitality | 2018 |
| Imperia Ltd | Transport & logistics | 2015 |
| Imra Advice Centre Ltd | Public administration | 2021 |
| IN the Therapist Chair Ltd | Health & social care | 2013 |
| IN Time Bar Ltd | Other services | 2025 |
| Inari Health Limited | Extraterritorial | 2019 |
| Independent Management Services Limited | Administrative & support | 2006 |
| Independent Scaffolding Services Limited | Other services | 1997 |
| Inder's Stores Ltd | Wholesale & retail | 2019 |
| Indian Law Practice and NRI Services Limited | Professional & scientific | 2013 |
| Indian London Film Company Ltd | Information & communication | 2023 |
| Indian Tiffin Room Ltd | Wholesale & retail | 2023 |
| Industrial Power Units Holdings Limited | Financial services | 2018 |
| Industrial Power Units Property Holdings Limited | Financial services | 2019 |
| Industrial Power Units Property Limited | Real estate | 1959 |
| Inest Ltd | Wholesale & retail | 2008 |
| Infamous Community Arts C.I.C. | Arts & recreation | 2011 |
| Inferno Media Limited | Information & communication | 2021 |
| Infinity Care Solutions Ltd | Health & social care | 2023 |
| Infinity Music Ltd | Arts & recreation | 2020 |
| Insight Society | Education | 2003 |
| Insignia Finance Limited | Financial services | 2007 |
| Inspire Midlands CIC | Other services | 2023 |
| Instafix Solutions Ltd | Wholesale & retail | 2024 |
| Instant Support 247 Ltd | Information & communication | 2017 |
| INT Food Plus Limited | Wholesale & retail | 2024 |
| Integral Electrical Services Limited | Manufacturing | 2010 |
| Integral Entrust Ltd | Wholesale & retail | 2021 |
| Integral Property Cleaning Ltd | Administrative & support | 2026 |
| Intelligent Candy Limited | Manufacturing | 2013 |
| Intellilife Limited | Wholesale & retail | 2025 |
| Intercraft Trading Co Limited | Wholesale & retail | 2022 |
| International Broadcast UK Ltd | Information & communication | 2021 |
| International Food Suppliers Limited | Other services | 2025 |
| Into UK Properties Ltd | Real estate | 2023 |
| Intuitive Freight Solutions Limited | Transport & logistics | 2009 |
| Ionut Limited | Transport & logistics | 2019 |
| IPU Group Holdco Limited | Financial services | 2024 |
| Iqsaexpress Ltd | Real estate | 2025 |
| Irie Flavorz Ltd | Extraterritorial | 2025 |
| IRR Network Ltd | Transport & logistics | 2015 |
| IRT Building Limited | Real estate | 2019 |
| IS Depot Limited | Wholesale & retail | 2022 |
| ISA Trading Ltd | Wholesale & retail | 2025 |
| Island Lounge Delivery Ltd | Wholesale & retail | 2024 |
| Islandlounge Wolves Ltd | Hospitality | 2026 |
| Istanbul Stratford Limited | Hospitality | 2025 |
| IT MOB Limited | Administrative & support | 2008 |
| IT Refurb Ltd | Other services | 2019 |
| It's ALL About Skin Ltd | Other services | 2026 |
| ITR Hospitality Limited | Hospitality | 2019 |
| Itsamazaleen Limited | Manufacturing | 2025 |
| Itswb Ltd | Administrative & support | 2016 |
| Iysha Ltd | Wholesale & retail | 2021 |
| J & P Construction Midland Ltd | Construction | 2021 |
| J & S Property Maintenance and Services Ltd | Real estate | 2023 |
| J and R Worldwide Produce Ltd | Wholesale & retail | 2021 |
| J B 1 Group Limited | Financial services | 2015 |
| J B 1 Hire Limited | Administrative & support | 2020 |
| J B 1 Properties Limited | Real estate | 2015 |
| J B Construction 1 Limited | Construction | 2009 |
| J B Developments 1 Limited | Construction | 2018 |
| J B Plant Limited | Administrative & support | 2014 |
| J D L Electrical Services Ltd | Construction | 2007 |
| J Dibra Ltd | Wholesale & retail | 2020 |
| J F Towcester Ltd | Administrative & support | 2022 |
| J K Building Supplies (WB) Limited | Wholesale & retail | 2019 |
| J P Convenience Store Ltd | Wholesale & retail | 2019 |
| J S Spinney Ltd | Hospitality | 2017 |
| J UK Transport Ltd | Transport & logistics | 2025 |
| J&J Branding Limited | Wholesale & retail | 2024 |
| J&M Natural and Authentic African Caribbean Products Ltd | Hospitality | 2018 |
| J&R Chatha Construction Ltd | Construction | 2023 |
| J.D. Electrical & Mechanical Services Limited | Construction | 2004 |
| J.H. Lavender & Company Limited | Manufacturing | 1994 |
| J.P.A. Homes Ltd | Real estate | 2021 |
| J.R.S Slinger Services Ltd | Construction | 2018 |
| J.S.C. (UK) Limited | Transport & logistics | 2009 |
| J.Sydney Ault,Limited | Financial services | 1911 |
| J1 Roofing Ltd | Construction | 2020 |