| I10 Networks Ltd | Financial services | 2017 |
| I12 Properties Limited | Real estate | 2019 |
| I3 Consultancy Limited | Other services | 2006 |
| I3-CONTROLS Ltd | Manufacturing | 2025 |
| IA Future Investments Limited | Real estate | 2022 |
| IA L Investments Limited | Real estate | 2022 |
| Ia&D Ltd | Real estate | 2022 |
| IA2MEDICALS Ltd | Professional & scientific | 2018 |
| IA2PROPERTIES Limited | Real estate | 2021 |
| IAC One Ltd | Hospitality | 2019 |
| IAC UK Holdings Ltd | Financial services | 2026 |
| IAH Electronic Industries Ltd | Wholesale & retail | 2010 |
| Iain Brown IT Solutions Ltd | Information & communication | 2012 |
| Iain Cart Limited | Wholesale & retail | 2015 |
| Ialphax Ltd | Information & communication | 2024 |
| IAN Davies Welding Equipment Limited | Wholesale & retail | 2002 |
| IAN Gillan 75 Ltd | Professional & scientific | 2023 |
| IAN Howes Limited | Information & communication | 2003 |
| IAN R. Monk Electrical Limited | Construction | 2002 |
| IAN Ramsden (Telecoms) Limited | Wholesale & retail | 2003 |
| IAN Randall Plumbing & Heating Limited | Construction | 2009 |
| IAN Swirles Limited | Extraterritorial | 2024 |
| Iannis Football Club Ltd | Arts & recreation | 2019 |
| IAR Properties Ltd | Households | 2020 |
| IAS Capital Ltd | Real estate | 2023 |
| Iass Ltd | Professional & scientific | 2015 |
| Iatroregenesis Ltd | Health & social care | 2013 |
| IAV Imports Limited | Wholesale & retail | 2020 |
| IAZ Capital Limited | Professional & scientific | 2021 |
| IB Builder Ltd | Construction | 2023 |
| IB Buy Ltd | Wholesale & retail | 2024 |
| IB Clothing Ltd | Manufacturing | 2022 |
| IB Coaching Ltd | Arts & recreation | 2005 |
| IB Consult Limited | Information & communication | 2025 |
| IB UK Logistic Ltd | Extraterritorial | 2021 |
| Ibadat Transport Ltd | Transport & logistics | 2025 |
| IBC Advisory LLP | | 2012 |
| IBC Children’S Services Ltd | Education | 2021 |
| IBC Health Care Group Ltd | Financial services | 2024 |
| IBC Health Care Ltd | Health & social care | 2020 |
| IBC Quality Solutions Limited | Public administration | 2012 |
| Iberian Contractors and Quantity Surveying Ltd | Construction | 2020 |
| Ibex Medical Services Ltd | Health & social care | 2020 |
| Ibex Properties (Leicester) Limited | Real estate | 2024 |
| Ibmb&Co Ltd | Real estate | 2025 |
| IBN Daud Books Limited | Information & communication | 2020 |
| IBN Daud Consulting Ltd | Construction | 2003 |
| IBN Drivers Limited | Transport & logistics | 2014 |
| IBN Leicester Limited | Hospitality | 2025 |
| Ibolya Services Limited | Administrative & support | 2019 |
| Ibosay Ltd | Hospitality | 2025 |
| Ibot Services Ltd | Construction | 2024 |
| IBR Motors Ltd | Wholesale & retail | 2019 |
| Ibra Auto & Tyres Ltd | Wholesale & retail | 2017 |
| Ibra Autos Centre Limited | Wholesale & retail | 2022 |
| Ibra Cars Ltd | Wholesale & retail | 2024 |
| Ibrahim's Halal Meat Ltd | Wholesale & retail | 2018 |
| Ibrahimi Property Investment Limited | Real estate | 2025 |
| Ibrak Limited | Hospitality | 2020 |
| Ibrar Sayed Ltd | Wholesale & retail | 2025 |
| Ibraz Hussain Healthcare Ltd | Health & social care | 2021 |
| Ibrokr Ltd | Financial services | 2025 |
| Ibsa Fashion Limited | Manufacturing | 2019 |
| Ibstock Retail Limited | Real estate | 2019 |
| Ibthorpe Logistics Ltd | Transport & logistics | 2014 |
| IC Construct Design Ltd | Construction | 2025 |
| IC Workforce Solutions Group Ltd | Professional & scientific | 2010 |
| Icaht Education Ltd | Education | 2019 |
| Icaht Limited | Health & social care | 2018 |
| Icall Care Limited | Health & social care | 2013 |
| Ican - the Inclusion and Cultural Awareness Network Ltd | Other services | 2023 |
| Icare 24/7 Limited | Health & social care | 2023 |
| Icare Homes Care Group Ltd | Health & social care | 2026 |
| Icarus Asset Management Group Ltd | Real estate | 2026 |
| Ice & Rose Ltd | Wholesale & retail | 2022 |
| Ice Cool Air Conditioning Limited | Construction | 2003 |
| Ice International Ltd | Wholesale & retail | 2023 |
| Ice Lett UK Ltd | Real estate | 2026 |
| Ice Tunnel Properties Ltd | Real estate | 2016 |
| Ice Utilities Ltd | Water & waste | 2019 |
| Ice.Me.Out.Official Ltd | Other services | 2024 |
| ICE2O Trading Limited | Wholesale & retail | 2024 |
| Iced OUT Services Limited | Administrative & support | 2025 |
| Icelandic Skyr Limited | Wholesale & retail | 2015 |
| Iceramics Ltd | Manufacturing | 2009 |
| Icicle Group Ltd | Wholesale & retail | 2025 |
| Ickburgh Logistics Ltd | Transport & logistics | 2014 |
| Icon FLY Limited | Administrative & support | 2026 |
| Icon Network Solutions Limited | Information & communication | 2007 |
| Icon People Recruitment Limited | Administrative & support | 2026 |
| Icon Real Estate Limited | Real estate | 2022 |
| Icon SL Ltd | Other services | 2014 |
| Icon Star Constructions Limited | Construction | 2026 |
| Icon Study Immigration Ltd | Professional & scientific | 2025 |
| Iconic Music, Drama and Dance Ltd | Arts & recreation | 2012 |
| Iconic Structure & Shopfitting Ltd | Other services | 2017 |
| Iconic Walls Limited | Wholesale & retail | 2024 |
| Iconnect Logistics Ltd | Transport & logistics | 2022 |
| Icpa Limited | Other services | 2001 |
| ICT Independent Consulting (Ictic) Limited | Information & communication | 2010 |