| IB Properties Overseas Limited | Real estate | 2018 |
| IBS Cannock Limited | Health & social care | 2019 |
| Ice Mixers Limited | Manufacturing | 2025 |
| ICL Medical Limited | Health & social care | 2026 |
| Icon Exhibitions and Display Ltd | Manufacturing | 1995 |
| Iconic EYE Music Ltd | Information & communication | 2017 |
| IDC Cleaning Ltd | Administrative & support | 2020 |
| IDE Rental Limited | Administrative & support | 2014 |
| IDE Systems (Holdings) Limited | Financial services | 2014 |
| IDE Systems Limited | Manufacturing | 2003 |
| IGF Consulting Limited | Professional & scientific | 2017 |
| Ignition Imports Ltd | Wholesale & retail | 2020 |
| IGU Group Limited | Other services | 2016 |
| Ikon Residence Ltd | Construction | 2017 |
| Ikrupa Trading Ltd | Wholesale & retail | 2023 |
| Imacs Limited | Professional & scientific | 1997 |
| Imagineight Limited | Professional & scientific | 2011 |
| Imaging Equipment Services Limited | Manufacturing | 2015 |
| IMF Rendering Ltd | Construction | 2021 |
| Immediatehr Ltd | Administrative & support | 2023 |
| Impact Treescape Limited | Other services | 2006 |
| Imperial Records Ltd | Transport & logistics | 2015 |
| Impulse Care UK Ltd | Health & social care | 2017 |
| IN the Know Solutions Ltd | Professional & scientific | 2022 |
| IN2 Real Estate Limited | Construction | 2022 |
| IN2 Real Estate Number 1 Limited | Real estate | 2024 |
| Inchinnan Solar Limited | Financial services | 2024 |
| Inchinnan Solar South Limited | Financial services | 2025 |
| Inco Construction Group Ltd | Financial services | 2020 |
| Inco Contracts Limited | Construction | 2010 |
| Individual Bust Group Limited | Wholesale & retail | 2018 |
| Indulgence With a Twist Limited | Wholesale & retail | 2018 |
| Industrial Control Services Ltd | Professional & scientific | 2018 |
| Industry Solutions Group Limited | Financial services | 2023 |
| Inet Ventures Ltd | Information & communication | 2013 |
| Infinity Black Construction Ltd | Construction | 2018 |
| Infinity Property Improvements Limited | Construction | 2014 |
| Infinity Remaps Ltd | Wholesale & retail | 2015 |
| Infinity Roofing Experts Limited | Extraterritorial | 2014 |
| Infinity Toyz Ltd | Wholesale & retail | 2019 |
| Infinity X Investments Limited | Financial services | 2026 |
| Infoforge Limited | Information & communication | 2024 |
| Inovaplus Limited | Professional & scientific | 2002 |
| Inside Air Limited | Energy | 2006 |
| Insight HR Limited | Other services | 2015 |
| Insight Recruitment Consultants Limited | Administrative & support | 2010 |
| Insightdx Consulting Limited | Health & social care | 2026 |
| Inspire Plates Ltd | Wholesale & retail | 2022 |
| Inspired Homes Group Ltd | Real estate | 2021 |
| Instant Print (Staffs) Limited | Information & communication | 2019 |
| Insuristic Limited | Financial services | 2022 |
| Intamarble Limited | Construction | 1991 |
| Integral Workplace Wellness Ltd | Education | 2020 |
| Integrity Bedrooms Limited | Administrative & support | 2017 |
| Intel Peptides Limited | Professional & scientific | 2026 |
| Intelec Design Solutions Ltd | Construction | 2017 |
| Intelligent CF Limited | Financial services | 2018 |
| Interactive Licensing Management Europe Limited | Administrative & support | 2015 |
| Interactive Licensing Management Limited | Information & communication | 2005 |
| Intercity and Rural Infrastructure Services Limited | Construction | 2025 |
| Interclean Estate Management Services Limited | Administrative & support | 2006 |
| Interior by Design Limited | Administrative & support | 2010 |
| International Patient Services Limited | Health & social care | 2018 |
| Interwaste Municipal Limited | Manufacturing | 2006 |
| Intrabray Payroll & Accountancy Services Limited | Professional & scientific | 2020 |
| Inventive Business Solutions Limited | Professional & scientific | 2011 |
| Iomni Health Ltd | Information & communication | 2026 |
| Ireland Electrical Ltd | Manufacturing | 2025 |
| Iris Telecoms Ltd | Construction | 2021 |
| Irongate Works Limited | Information & communication | 2026 |
| Ironhorse Motorcycles Ltd | Wholesale & retail | 2023 |
| Ironwork Holdings Limited | Professional & scientific | 2021 |
| Islands Homes Limited | Real estate | 2025 |
| Isleham Developments Ltd | Construction | 2026 |
| Isolutions (Midlands) Limited | Information & communication | 2017 |
| Issp Construction Ltd | Construction | 2025 |
| Ivebelt Ltd | Professional & scientific | 2023 |
| IW Municipal Services Limited | Manufacturing | 2014 |
| Iwonderwhatsnext Limited | Wholesale & retail | 2021 |
| J & a Investment Properties Ltd | Households | 2003 |
| J & H Plumbing Ltd | Construction | 2025 |
| J & J Services ( Midlands ) Ltd | Other services | 2010 |
| J & K Window Cleaning Services Limited | Administrative & support | 2022 |
| J & M Bannister Limited | Professional & scientific | 2021 |
| J & M Bannister Properties Limited | Hospitality | 2021 |
| J & R T Property Limited | Real estate | 2026 |
| J & S Decorators (UK) Limited | Administrative & support | 2007 |
| J & S Floors (Midlands) Limited | Extraterritorial | 2005 |
| J a Waste Removals (1966) Limited | Water & waste | 2026 |
| J Barrett Company Ltd | Construction | 2025 |
| J Biscuit Consultancy Ltd | Information & communication | 2018 |
| J Hadley Properties Ltd | Real estate | 2018 |
| J Harris Roofing Ltd | Construction | 2025 |
| J J Brokers Ltd | Financial services | 2018 |
| J K Edwards Limited | Administrative & support | 2016 |
| J L Minton Plastering Limited | Construction | 2004 |
| J L Plastering Ltd | Construction | 2023 |
| J M Fleetwash Limited | Wholesale & retail | 2012 |
| J Mason Associates Limited | Professional & scientific | 2004 |
| J O'Day Interiors Ltd | Construction | 2016 |