| Inventure Stamford Street Ltd | Wholesale & retail | 2025 |
| Inventure Warren Street Ltd | Wholesale & retail | 2012 |
| Inverse Studios Ltd | Information & communication | 2017 |
| Investor in Sme's Ltd. | Administrative & support | 2019 |
| Invirtiendo Limited | Financial services | 2022 |
| IO Medics Ltd | Wholesale & retail | 2025 |
| Ionutraducanu Ltd | Transport & logistics | 2019 |
| IPC Emea Ltd | Hospitality | 2023 |
| IPC Europe Ltd | Hospitality | 2019 |
| Iproperty Cloud Ltd | Information & communication | 2021 |
| IPV Ventures Ltd | Hospitality | 2018 |
| Iqab Limited | Wholesale & retail | 2025 |
| Iqca Ltd | Education | 2024 |
| IR Health Limited | Health & social care | 2023 |
| IR Lighting Limited | Professional & scientific | 2011 |
| IRA Healthcare Ltd | Wholesale & retail | 2023 |
| Ireland Creative Ltd | Professional & scientific | 2026 |
| Iris Organics Limited | Wholesale & retail | 2019 |
| Irismay CIC | Health & social care | 2024 |
| Irrigation Engineers International Ltd | Professional & scientific | 2020 |
| Irrigation Engineers Limited | Professional & scientific | 2010 |
| IRT Ltd | Professional & scientific | 2024 |
| Isaac Estate Agent Ltd | Real estate | 2019 |
| Isaac Lord Limited | Wholesale & retail | 1948 |
| Isabella Barrand Counselling and Supervision Ltd | Health & social care | 2024 |
| Isdc Global Services Limited | Education | 2017 |
| Isdc Education Infrastructure Limited | Education | 2019 |
| Isha Sadiq Consulting Limited | Other services | 2026 |
| Ishaq Investments Ltd | Real estate | 2024 |
| Isher Capital Development Limited | Construction | 2025 |
| Ishfaq Property Ltd | Real estate | 2025 |
| Ishkara Ltd | Professional & scientific | 2026 |
| Isla & James Holdings Ltd | Real estate | 2020 |
| Island Enterprises Limited | Real estate | 2021 |
| Island Luxury Representation Ltd | Administrative & support | 2021 |
| Island Sheds Limited | Wholesale & retail | 2017 |
| Island Style Ltd | Hospitality | 2025 |
| Island Waste Services Limited | Water & waste | 1981 |
| Isleforce Flat Management Company Limited | Real estate | 1991 |
| Ismaeel Peri Peri Ltd | Hospitality | 2025 |
| Isobel MAY Interiors Ltd | Professional & scientific | 2025 |
| Isotemp(Heating & Ventilating)Limited | Construction | 1963 |
| Isotherm Building Services Ltd | Construction | 2026 |
| Isotope Medical Limited | Real estate | 2006 |
| ISR Counselling Limited | Administrative & support | 2012 |
| Istanbul High Wycombe Ltd | Wholesale & retail | 2024 |
| IT Adds UP Limited | Professional & scientific | 2011 |
| IT BIZ Support Limited | Information & communication | 2014 |
| IT Business Group Limited | Wholesale & retail | 2002 |
| IT Cloud Limited | Information & communication | 2016 |
| IT Consumables Limited | Professional & scientific | 1999 |
| IT Homez Ltd | Construction | 2023 |
| IT Solution & Technology Ltd | Information & communication | 2021 |
| IT Solution 4U Ltd | Information & communication | 2024 |
| Ital Moss Ltd | Wholesale & retail | 2020 |
| Itbg Holdings Limited | Financial services | 2018 |
| Itbg Property Limited | Financial services | 2018 |
| Itcs Construct Solution Limited | Construction | 2022 |
| Itcs Developments Ltd | Real estate | 2025 |
| Itecheuro PVT Ltd | Information & communication | 2021 |
| Ithub Ltd | Information & communication | 2009 |
| Itomino Ltd | Transport & logistics | 2019 |
| Itoms Ltd | Information & communication | 2026 |
| ITS Builders Limited | Construction | 2021 |
| Iver Curry& Tandoori Centre Limited | Hospitality | 2010 |
| Ives & Taylor (Holdings) Limited | Financial services | 2005 |
| Ives & Taylor Group Limited | Financial services | 2016 |
| Ives & Taylor Insurances Limited | Financial services | 1965 |
| Ivista Limited | Professional & scientific | 2007 |
| Iviv Cutting Services Ltd | Manufacturing | 2020 |
| Ivory Coaches Limited | Transport & logistics | 2023 |
| IVY Taxis Ltd | Transport & logistics | 2015 |
| Iwanski Design Co. Ltd | Manufacturing | 2016 |
| Iwholesales Limited | Arts & recreation | 2011 |
| IWL Hayes Ltd | Real estate | 2022 |
| IWL Holdings Ltd | Real estate | 2016 |
| Ixura Group Ltd | Professional & scientific | 2026 |
| IYP Logistics Ltd | Transport & logistics | 2022 |
| Izaa Health Essentials Ltd | Health & social care | 2023 |
| Izmarealestate Ltd | Real estate | 2025 |
| J & K Foods Limited | Hospitality | 2020 |
| J & L Building Maintenance Limited | Construction | 2006 |
| J & S Auto Repairs Ltd | Wholesale & retail | 2003 |
| J & Y Services Ltd | Transport & logistics | 2026 |
| J a H Plumbing Limited | Construction | 2017 |
| J Ahmed Investments Ltd | Real estate | 2025 |
| J Atherley Creative Limited | Professional & scientific | 2016 |
| J Barker Fitness Ltd | Education | 2024 |
| J Chan Solutions Limited | Information & communication | 2017 |
| J Chilver Ltd | Professional & scientific | 2024 |
| J Corley Consulting Ltd | Financial services | 2021 |
| J Davis Builders Ltd | Construction | 2019 |
| J Hardingham (Chef) Limited | Hospitality | 2022 |
| J Ikigai Ltd | Administrative & support | 2017 |
| J J Fernandes Limited | Construction | 2026 |
| J J Field Associates Limited | Professional & scientific | 2013 |
| J J Jones Limited | Information & communication | 2015 |
| J Nissi Limited | Information & communication | 2019 |
| J Property Group Ltd | Real estate | 2020 |
| J R Fernandes Limited | Health & social care | 2000 |