| ICB Direct Limited | Education | 2005 |
| ICB Global | Education | 2006 |
| ICB International Limited | Education | 1999 |
| ICB Member Services Ltd | Education | 2015 |
| ICD Trans Ltd | Transport & logistics | 2024 |
| Ice Legal Consultancy Ltd | Professional & scientific | 2019 |
| Ice Property Investments Ltd | Real estate | 2021 |
| Iceman Consulting Limited | Administrative & support | 2010 |
| ICG Site Facilities Management Ltd | Energy | 2025 |
| Iconiq Investments Limited | Real estate | 2025 |
| ICS Group Enterprises Ltd | Information & communication | 2015 |
| ID Removals Ltd | Transport & logistics | 2025 |
| Ideal Farm Management Limited | Professional & scientific | 2018 |
| Ideal Glass H Limited | Construction | 2026 |
| Ideational Limited | Professional & scientific | 2005 |
| Identity Invest UK Limited | Professional & scientific | 2022 |
| IDL Associates Ltd | Information & communication | 2025 |
| Idle Rocket Limited | Manufacturing | 2016 |
| Idreesia Auto Limited | Wholesale & retail | 2013 |
| IDV Pro Limited | Information & communication | 2006 |
| Iebest Limited | Professional & scientific | 2020 |
| Ieo&Co Ltd | Professional & scientific | 2021 |
| Iethos Medical Limited | Other services | 2016 |
| Iftkhar Rasool Mirza Limited | Extraterritorial | 2024 |
| IG Installations Limited | Construction | 2003 |
| IGA Construction Ltd | Construction | 2019 |
| Igfm Ltd | Administrative & support | 2012 |
| Ignite 4T Personal Training Ltd | Other services | 2017 |
| Ignite Solutions Limited | Professional & scientific | 2008 |
| Ignite XL Ltd | Professional & scientific | 2023 |
| IGP Solutions Limited | Construction | 2008 |
| IGS3 Traders Limited | Wholesale & retail | 2013 |
| Ihleaver Ltd | Arts & recreation | 2019 |
| Ihsaan Ventures Ltd | Professional & scientific | 2026 |
| IIA Accountancy Limited | Professional & scientific | 2020 |
| IJ Cleaning Co Limited | Administrative & support | 2025 |
| Ijadi Interior Groups Ltd | Professional & scientific | 2024 |
| IJG Consulting Ltd | Information & communication | 2019 |
| IK Autohause Ltd | Wholesale & retail | 2025 |
| IK Barbers Ltd | Other services | 2025 |
| IKD Estates Ltd | Real estate | 2025 |
| Ikhlaq Ghafoor Ltd | Construction | 2024 |
| Ikigai Education and Care Group Ltd | Education | 2024 |
| Ikigai Properties Ltd | Real estate | 2025 |
| Ikpydev Limited | Information & communication | 2024 |
| IL Gusto (Lincs) Limited | Hospitality | 2018 |
| IL Gusto Middle East Limited | Wholesale & retail | 2019 |
| Ileri Trading Limited | Wholesale & retail | 2015 |
| Illucia Limited | Information & communication | 2026 |
| Ilmora Solutions Ltd | Information & communication | 2025 |
| Ilpra Systems U.K. Limited | Wholesale & retail | 1990 |
| IM Cars Ltd | Extraterritorial | 2023 |
| IM Real Estate Limited | Construction | 2023 |
| Image Creation Limited | Professional & scientific | 1998 |
| Image Creation Trustees Limited | Administrative & support | 2017 |
| Image Express Limited | Extraterritorial | 1989 |
| Imagework Media Limited | Professional & scientific | 2011 |
| Imagineers Limited | Manufacturing | 1985 |
| IMC Construction Ltd | Construction | 2018 |
| IME1 Investments Ltd | Construction | 2025 |
| IMF Property Investments Limited | Real estate | 2022 |
| Immigraite AI Limited | Information & communication | 2024 |
| Immigration Navigator Ltd | Education | 2021 |
| IMO Car Wash Group Limited | Professional & scientific | 2009 |
| Impact Guarding Solutions Ltd | Administrative & support | 2019 |
| Impacta AI Limited | Information & communication | 2026 |
| Imperative Gadgets Ltd | Wholesale & retail | 2021 |
| Imperial Grove (Camlet Way) Company Limited | Households | 2016 |
| Imperial Grove (Hadley Wood) Management Company Limited | Households | 2013 |
| Impermanent Limited | Information & communication | 2024 |
| Impressions Orthodontics Limited | Health & social care | 2015 |
| Improveright Group Limited | Real estate | 2016 |
| Impulse Electrical Solutions Limited | Construction | 2010 |
| Imrose Ltd | Transport & logistics | 2026 |
| IMU Technology Ltd | Wholesale & retail | 2022 |
| IN Time Gifts Ltd | Wholesale & retail | 2014 |
| IN Time Taxis Limited | Transport & logistics | 2025 |
| In-Motion Limited | Wholesale & retail | 2009 |
| In-Time Properties and Investment Ltd | Households | 2025 |
| Inaar Properties Limited | Real estate | 2022 |
| Inbulk Ltd | Wholesale & retail | 2023 |
| Inbyld Ltd | Construction | 2022 |
| Incendium Wildfire Solutions Limited | Public administration | 2022 |
| Inchprop Limited | Real estate | 2002 |
| Inclusion UN. Ltd | Health & social care | 2018 |
| Incredible Sports Company Ltd | Wholesale & retail | 2012 |
| Independent and Work Ready CIC | Health & social care | 2019 |
| Independent Guest Ltd | Transport & logistics | 2010 |
| Independent Live-In Care Ltd | Health & social care | 2024 |
| Independent Purchasing Group Ltd | Hospitality | 2024 |
| Independent Technical Services Limited | Administrative & support | 2002 |
| Index Web Solutions Limited | Information & communication | 2024 |
| Indian Dine Ltd | Hospitality | 2023 |
| Indian Nite Ltd | Hospitality | 2025 |
| Indigo and Rose Homeware Ltd | Wholesale & retail | 2010 |
| Indogulf Uniforms Limited | Wholesale & retail | 2025 |
| Indoor Football Ltd | Arts & recreation | 2015 |
| Induce Drip Ltd | Wholesale & retail | 2025 |
| Industrial Pipe Services (2003) Ltd | Administrative & support | 2003 |
| Infinity Installations Ltd | Construction | 2023 |