| Innovative Solutions (UK) Limited | Manufacturing | 1998 |
| Inspire Personnel Limited | Construction | 2017 |
| Instasurge Limited | Other services | 2014 |
| Instrumental Services Ltd | Professional & scientific | 2018 |
| Integral Mechanical & Welding Ltd | Manufacturing | 2025 |
| Integrated Fabrications Limited | Administrative & support | 2002 |
| Integrated House Limited | Real estate | 2023 |
| Integrated Property Solutions Ltd | Construction | 2020 |
| Intelligent I.D. Limited | Wholesale & retail | 2002 |
| Intelligent Optometric Services Ltd | Health & social care | 2015 |
| Intelligent Panel Systems Ltd | Construction | 2024 |
| Interactive Business Limited | Education | 2003 |
| Interafrica Logistics Ltd | Wholesale & retail | 2025 |
| Intercare Plus Healthcare Ltd | Other services | 2016 |
| Interior Building Projects Limited | Construction | 2016 |
| Internal Eco Solutions Ltd | Construction | 2025 |
| International Chippy Ltd | Hospitality | 2015 |
| International Education Counselling Centre UK Ltd | Education | 2025 |
| Into Skills for Care and Counselling Ltd | Health & social care | 2019 |
| Invapro Ltd | Real estate | 2024 |
| Inventus Partners Ltd | Administrative & support | 2025 |
| Inversify Limited | Real estate | 2019 |
| Invest Property Maintenance Ltd | Real estate | 2011 |
| Investico Holdings Limited | Financial services | 2024 |
| Investico Rochdale Ltd | Real estate | 2024 |
| Investico Smart Investment Ltd | Real estate | 2024 |
| Inviation Ltd | Wholesale & retail | 2022 |
| Invitari Limited | Administrative & support | 2014 |
| Inxpress Franchising Ltd | Professional & scientific | 2013 |
| Inxpress Global Limited | Professional & scientific | 2012 |
| Inxpress Holdings Ltd | Financial services | 2018 |
| Inxpress Limited | Professional & scientific | 2003 |
| Inxpress SF 1 UK Limited | Transport & logistics | 2025 |
| Inxpress SF 2 UK Limited | Transport & logistics | 2025 |
| Inxpress SF 3 UK Limited | Transport & logistics | 2025 |
| Inxpress SF Holdco UK Limited | Financial services | 2025 |
| Inxpress SF Top Holdco Limited | Financial services | 2025 |
| IO Square Consultants Ltd | Health & social care | 2021 |
| IP Signposting 1 Ltd | Information & communication | 2021 |
| Ipro Property Renovations Ltd | Construction | 2025 |
| IQ Mouldings Limited | Manufacturing | 2015 |
| Iqbal Cultural & Community Centre Ltd | Other services | 2020 |
| Iqbal DIN Limited | Other services | 2024 |
| Iqra Group Property Ltd | Real estate | 2023 |
| Iqra International Trading Limited | Administrative & support | 2017 |
| Iqra Medical Services Ltd | Health & social care | 2019 |
| IQRA2005 Limited | Hospitality | 2022 |
| Irfan & Iram Ltd | Financial services | 2023 |
| IRK Developments Ltd | Real estate | 2024 |
| IRM Construction Ltd | Construction | 2024 |
| Ironclad Strategies Ltd | Information & communication | 2025 |
| Irshad Property Ltd | Real estate | 2023 |
| Irvine Yates Consultancy Limited | Administrative & support | 2019 |
| Irvine Yates Limited | Professional & scientific | 2017 |
| Isaac BED Company Ltd | Manufacturing | 2025 |
| Isaac Butterworth (Ironfounders) Limited | Manufacturing | 1948 |
| Isaac Butterworth Limited | Professional & scientific | 2004 |
| Isight (NW) Ltd | Other services | 2014 |
| Islamabad Auto Repair Ltd | Wholesale & retail | 2024 |
| Ismun Ltd | Wholesale & retail | 2022 |
| ISN Property Ltd | Real estate | 2021 |
| Isobel Properties Ltd | Hospitality | 2025 |
| Isports Rochdale FC Academy Ltd | Arts & recreation | 2016 |
| Israr Services Ltd | Health & social care | 2024 |
| Issey’S Trade Limited | Manufacturing | 2025 |
| Isssentals Ltd | Wholesale & retail | 2024 |
| Istanbul New Style Barber Shop Ltd | Other services | 2021 |
| Isti'Dad CIC | Education | 2025 |
| Istock Warehouse Ltd | Wholesale & retail | 2022 |
| Istyleuk Ltd | Wholesale & retail | 2025 |
| ISW Care Services Ltd | Professional & scientific | 2018 |
| ISW CSC Limited | Health & social care | 2016 |
| Iswa Ltd | Wholesale & retail | 2020 |
| IT Relations Limited | Wholesale & retail | 2023 |
| It's a Smash Ltd | Hospitality | 2025 |
| It's Good Practice Ltd | Professional & scientific | 2011 |
| Itbotsolutions Ltd | Information & communication | 2026 |
| Itna Traders Ltd | Wholesale & retail | 2024 |
| Itreatskin Limited | Manufacturing | 2017 |
| Itronik Limited | Wholesale & retail | 2019 |
| ITS a Wrap Ltd | Hospitality | 2024 |
| ITS ALL in the Image Ltd | Manufacturing | 2013 |
| Iustitia Ltd | Professional & scientific | 2023 |
| Ivori Studio Ltd | Real estate | 2026 |
| IVY Rose Property Limited | Construction | 2024 |
| IWA Card Company Limited | Wholesale & retail | 2026 |
| IXP Manchester Ltd | Transport & logistics | 2003 |
| IY Estates Ltd | Real estate | 2024 |
| IY Optical Consultancy Ltd | Wholesale & retail | 2019 |
| Iyan Linens Ltd | Wholesale & retail | 2017 |
| IZW Logistics Ltd | Transport & logistics | 2023 |
| Izzy Fashion's Ltd | Wholesale & retail | 2023 |
| J & a Consultancy Ltd | Administrative & support | 2016 |
| J & D Landregan Ltd | Construction | 2008 |
| J & J Car & Commercial Vehicle Repair Ltd | Wholesale & retail | 2026 |
| J & J Takeaway Limited | Hospitality | 2026 |
| J & M Residential Lettings Limited | Real estate | 2008 |
| J & N Fitness Ltd | Arts & recreation | 2021 |
| J a Milton Upholstery Supplies Ltd | Wholesale & retail | 2007 |
| J a Mullaney Limited | Professional & scientific | 2012 |